The effect of postharvest chitosan, gallic acid (GA) and chitosan gallate (CG) dipping treatments... more The effect of postharvest chitosan, gallic acid (GA) and chitosan gallate (CG) dipping treatments at different concentrations on quality parameters, antioxidant compounds, free radical scavenging capacity (FRSC) and enzymes activities of 'Sukkari' bananas were studied during storage (ripening) at 20 ± 2 °C and 60-70% RH for 13 days. Weight loss and peel color index (the change from green to yellow) increased while, membrane stability index of peel tissues, pulp firmness and acidity decreased during storage. CG and GA treatments slowed down the changes in these parameters compared to control. Total soluble solids (TSS) concentration increased during storage and was lower at CG than other treatments. TSS/acid ratio increased during storage and showed higher value after storage than initial. This ratio was lower at 1% chitosan, 0.075% GA and CG treatments than control. Both vitamin C and total flavonoids concentrations decreased during storage and were not affected by the appli...
Effects of chitosan (1%), trans-resveratrol (resveratrol) (1.6 × 10 −5 M, 1.6 × 10 −4 M and 1.6 ×... more Effects of chitosan (1%), trans-resveratrol (resveratrol) (1.6 × 10 −5 M, 1.6 × 10 −4 M and 1.6 × 10 −3 M) and glycine betaine (GB) (10, 15 and 20 mM) dipping on quality and biochemical changes of 'Hindi-Besennara' mangoes during ripening at shelf life (SL) (18± 2 • C, 60-70% RH) were studied. Resveratrol, especially at low rate followed by GB, especially at high rate, decreased decay percentage after one and two weeks of SL compared to other treatments. Both compounds at all rates retained higher fruit firmness during SL and higher titratable acidity (TA) (only after one week of SL). Both GB and resveratrol at all rates retained higher vitamin C level than control with no effect on total soluble solids (TSS) after two weeks of SL. These compounds had no effect on weight loss after one week, but increased it after two weeks of SL compared to control. Chitosan showed higher weight loss during SL but, retained higher TA and vitamin C, and lower pH with no significant impact on firmness, TSS and decay compared to control. Chitosan, low and medium resveratrol rates, and low and high GB rates maintained higher membrane stability of peel after two weeks of SL compared to control. All treatments showed lower ␣-amylase but, higher peroxidase (POD) activities in peel than control after two weeks of SL. High resveratrol rate retained higher total phenols level than control, in contrast to chitosan after two weeks of SL while, total flavonoids was not affected. Compared to initial, peel free radical scavenging capacity (FRSC) decreased after one week followed by a sharp increase after two weeks of SL. Chitosan, medium and high resveratrol rates, and medium GB rate showed higher FRSC than control after one week of SL but, with no differences after two weeks of SL. In conclusion, both trans-resveratrol and GB treatments retained quality of 'Hindi-Besennara' mangoes during SL and being suggested as natural alternatives to synthetic chemicals.
A field experiment was conducted in 2011 and 2012 to study the effect of fertigation on yield, fr... more A field experiment was conducted in 2011 and 2012 to study the effect of fertigation on yield, fruit quality and nutrient uptake of 'Nabbut-Ahmar' date palm cultivar grown in sandy loam soil. Three fertigation treatments were compared with traditional application. In traditional treatment (CT), the recommended dose [2300 g nitrogen (N), 1200 g phosphorus (P) and 1400 g/ tree] was applied as a soil broadcast in three equal doses. The fertigation treatments, (T2), (T3) and (T4), represent all nitrogen, phosphorus and potassium (NPK) amounts of CT, 2/3 CT and 1/3 CT, respectively that were injected in twelve equal doses. The results showed that compared to CT, the fertigation treatments increased yield/palm by 41%, 31% and 18% for T3, T2 and T4, respectively. Beside the increase in yield, 33% and 66% of the applied fertilizers were saved by T3 and T4, respectively, compared with CT. Feritgation treatments had no negative impact on the overall fruit quality characteristics and even increased total soluble solids (TSS), soluble tannins and total phenols concentrations compared to the conventional fertilization. Availability of NPK increased by fertigation but without further increase in leaves and fruit. In conclusion applying 2/3 of the recommended dose of NPK fertilizers under dry land condition through fertigation maximize yield, quality and fertilizer use efficiency.
Biochemical changes in fruit of an early and a late date palm cultivar during development and rip... more Biochemical changes in fruit of an early and a late date palm cultivar during development and ripening (2011) International Journal of Fruit Science, 11 (2), pp. 167-183. Cited 1 time.
Effects of chitosan (1%), trans-resveratrol (resveratrol) (1.6 × 10 −5 M, 1.6 × 10 −4 M and 1.6 ×... more Effects of chitosan (1%), trans-resveratrol (resveratrol) (1.6 × 10 −5 M, 1.6 × 10 −4 M and 1.6 × 10 −3 M) and glycine betaine (GB) (10, 15 and 20 mM) dipping on quality and biochemical changes of 'Hindi-Besennara' mangoes during ripening at shelf life (SL) (18± 2 • C, 60-70% RH) were studied. Resveratrol, especially at low rate followed by GB, especially at high rate, decreased decay percentage after one and two weeks of SL compared to other treatments. Both compounds at all rates retained higher fruit firmness during SL and higher titratable acidity (TA) (only after one week of SL). Both GB and resveratrol at all rates retained higher vitamin C level than control with no effect on total soluble solids (TSS) after two weeks of SL. These compounds had no effect on weight loss after one week, but increased it after two weeks of SL compared to control. Chitosan showed higher weight loss during SL but, retained higher TA and vitamin C, and lower pH with no significant impact on firmness, TSS and decay compared to control. Chitosan, low and medium resveratrol rates, and low and high GB rates maintained higher membrane stability of peel after two weeks of SL compared to control. All treatments showed lower ␣-amylase but, higher peroxidase (POD) activities in peel than control after two weeks of SL. High resveratrol rate retained higher total phenols level than control, in contrast to chitosan after two weeks of SL while, total flavonoids was not affected. Compared to initial, peel free radical scavenging capacity (FRSC) decreased after one week followed by a sharp increase after two weeks of SL. Chitosan, medium and high resveratrol rates, and medium GB rate showed higher FRSC than control after one week of SL but, with no differences after two weeks of SL. In conclusion, both trans-resveratrol and GB treatments retained quality of 'Hindi-Besennara' mangoes during SL and being suggested as natural alternatives to synthetic chemicals.
Talh trees (Acacia gerrardii Benth.) are acacias that are native to the arid and semiarid Africa ... more Talh trees (Acacia gerrardii Benth.) are acacias that are native to the arid and semiarid Africa and west Asia. We investigated the flowering biology, pod set and flower visitors of Talh and discussed the role of these visitors in pollen transfer. The Talh trees blossomed laterally on the nodes of one-year-old twigs. Each node produced 21 flower buds seasonally. Each flower bud opened to a flower head (FH) of 60 florets. The bagged FHs podded significantly (p 6 0.05) less than did the unbagged FHs. The FHs were visited by 31 insect species (25 genera, 16 families and 5 orders). The major taxa were honeybees, megachilids, butterflies, ants, beetles and thrips. Each of honeybees, megachilids and beetles showed a significant (p 6 0.05) hourly pattern, while each of butterflies, ants and thrips had no hourly pattern (p > 0.05). Furthermore, some birds and mammals touched the Talh FHs. Talh trees evolved a mass flowering behavior to face preand post-flowering obstacles. Megachilids seemed to play the major effort of zoophily because of their relatively high numbers of individuals and species and their effective movement behavior on the FH surface. Nevertheless, honeybees and other insects and vertebrate taxa also contributed to the pollen transfer. These results greatly contribute to our understanding of the pollination ecology of acacias, especially Arabian acacias.
Potassium (K) is a critical element for date palm production especially under stress conditions. ... more Potassium (K) is a critical element for date palm production especially under stress conditions. During 2011 and 2012 seasons, two methods of K fertilization (K2SO4, 52% K2O) at different rates were evaluated on ‘Seweda’ date palm cultivar. The first method was soil broadcast (SB) of 2, 3 and 4 kg/palm in 3 equal doses (February, April and May). While in the second method, half of these amounts were applied as SB and the other half as foliar spray (FS) in 10 equal doses during growing season. The results showed no significant effect of K fertilization on either bunch weight or yield as the mean of two seasons. However, in 2012, the highest bunch weight and yield was at the 2 kg SB + 2 kg FS treatment while, the lowest values were at the 2 kg SB treatment. The highest rutab % obtained from the 2 kg SB treatment. Both fruit and flesh weight at the bisir stage were higher at the high rates of K applied as SB + FS than SB. Also, K concentration of leaves was higher in SB + FS than SB. K...
Variations in¯avonoid and chlorogenic acid levels within fruit, within tree, between orchards, be... more Variations in¯avonoid and chlorogenic acid levels within fruit, within tree, between orchards, between cultivars and among mutants were characterised and quanti®ed in`Elstar' and`Jonagold' apples by reversed-phase high performance liquid chromatography (RP-HPLC). The sun-exposed skin of individual fruit had much higher cyanidin 3-galactoside (anthocyanin) and quercetin 3glycoside levels than the shaded skin, while phloridzin, catechins and chlorogenic acid were similar in the skin of both sides. Individual¯avonoid and chlorogenic acid levels were not equally distributed within the fruit. Quercetin 3-glycosides and anthocyanin were almost exclusively found in the skin. Catechins were mostly found in the skin but some were present in the¯esh. Phloridzin was most abundant in the seeds, with intermediate levels in both the core area and the skin, and the lowest level in the¯esh. Chlorogenic acid was mainly present in the core area and the seeds with an intermediate level in the¯esh and a low level in the skin. The levels of anthocyanin, quercetin 3glycosides and total¯avonoids were highest in fruit borne in the top of the tree followed by fruit from the outer tree parts, whereas the lowest levels were found in fruit from the inner tree. Terminal fruit contained the highest levels of these compounds, including catechins, compared to lateral and spur fruit. Phloridzin and chlorogenic acid were not affected by the position of the fruit in the tree nor by the bearing wood type. There were large differences in¯avonoid and chlorogenic acid levels in`Elstar' fruit between two normally productive orchards differing mainly in growth vigour. Jonagold' and its mutants had considerably higher levels of¯avonoid and chlorogenic acid thaǹ Elstar' and its mutants. The most blushed mutants of both cultivars had higher levels of anthocyanin but not of¯avonoids or chlorogenic acid compared to the standard cultivar and to the less blushed mutants. The most blushed mutants had a higher number of red cells per cell layer and Scientia Horticulturae 83 (2000) 249±263
Quality characteristics of bisir 'Barhee' dates during cold storage as affected by postharvest di... more Quality characteristics of bisir 'Barhee' dates during cold storage as affected by postharvest dipping in gibberellic acid, naphthaleneacetic acid and benzyladenine. Abstract-Introduction. There is a growing demand in the international market for excellent-quality dates of cultivars such as 'Barhee' that are consumed at the bisir stage. Materials and methods. The effects of GA 3 , BA and NAA postharvest dipping treatments at different concentrations on the quality characteristics of bisir 'Barhee' dates during cold storage were investigated. Results and discussion. The total soluble solids (TSS) concentration was lower in the BA-and NAA-treated fruit than in control fruit. Similarly, the GA 3-treated fruit at 150 mg•L-1 contained a lower TSS concentration than control fruit. The GA 3 at 150 mg•L-1 , BA at 60 mg•L-1 and NAA at (100 and 150) mg•L-1 increased vitamin C concentration compared with other treatments. Acidity and total phenol concentrations were not affected by any of the treatments. The date soluble tannin concentration was higher than control fruit only in the dates treated with 20 mg BA•L-1. The weight loss % was lower in the BA-treated fruit at (20 and 60) mg•L-1 compared with all other treatments, while GA 3 treatment at 50 mg•L-1 increased fruit weight loss % compared with control fruit. The percentage of dates at the rutab stage (index for fruit ripening) was lower for fruit treated with GA 3 than for control fruit. Also, the rutab stage % was lower for fruit treated with BA at 40 mg•L-1 and NAA at 150 mg•L-1 compared with control fruit. The TSS concentration decreased during storage from the initial day to day 20. However, there were no further decreases in the TSS concentration after (40 and 60) days of storage. The acidity concentration was slightly increased during storage. The vitamin C concentration increased until 40 days of storage, then a slight decrease occurred. The total phenol concentration decreased after (40 and 60) days of storage compared with the initial level. The soluble tannin concentration slightly increased at day 20 but sharply decreased after (40 and 60) days of storage compared with the initial level. Both weight loss and rutab stage % gradually increased during storage. There were significant interaction effects between growth regulators and storage period on TSS, vitamin C concentration, weight loss and rutab stage %. Saudi Arabia / Phoenix dactylifera / fruits / developmental stages / cold storage / quality / chemicophysical properties / ripening / maturity Qualité des dates 'Barhee' au stade bisir stockées au froid après trempage post récolte dans l'acide gibbérellique, l'acide naphtalène et la benzyladénine. Résumé-Introduction. Il existe une demande croissante dans le marché international pour des dates d'excellente qualité telles que le sont celles du cultivar 'Barhee' qui sont consommées au stade bisir. Matériel et méthodes. Les effets du traitement de dates 'Barhee' au stade bisir par trempage après récolte dans des solutions de GA 3 , BA et ANA à différentes concentrations ont été étudiés sur certaines caractéristiques de qualité des fruits pendant leur stockage au froid. Résultats et discussion. La concentration en solubles solides totaux (SST) dans les fruits traités avec BA et NAA a été plus faible que dans les fruits témoins. De même, les fruits traités avec 150 mg GA 3 •L-1 ont montré une concentration de SST plus faible que les fruits témoins. Les traitements avec 150 mg GA 3 •L-1 , 60 mg BA•L-1 et (100 et 150) mg NAA•L-1 ont augmenté la concentration en vitamine C des dates par rapport aux autres traitements. L'acidité et la concentration en phénols totaux n'ont été affectés par aucun des traitements. La concentration en tanins solubles des dates traitées ne s'est révélée plus élevée que celle des fruits témoins que dans les fruits traités avec 20 mg BA•L-1. La perte de poids des fruits traités avec (20 et 60) mg BA•L-1 a été inférieure à celle des fruits de tous les autres traitements, tandis que le traitement à 50 mg GA 3 •L-1 a augmenté la perte de poids des dates par rapport aux fruits témoins. Le pourcentage de dates au stade rutab (indice de maturation des fruits) a été plus faible pour les fruits traités avec GA 3 que pour les fruits témoins. En outre, ce pourcentage a été plus faible pour les fruits traités avec 40 mg BA•L-1 et 150 mg NAA•L-1 que pour les fruits témoins. La concentration en SST a diminué du premier au vingtième jour de stockage. Cependant, il n'y a pas eu de nouvelles baisses de cette concentration après (40 et 60) jours de stockage. L'acidité a été légèrement augmentée durant le stockage. La concentration en vitamine C a augmenté jusqu'à 40 jours de stockage, puis une légère baisse s'est produite. La concentration totale en phénols a diminué après (40 et 60) jours de stockage par rapport au niveau de départ. La concentration des tanins solubles a légèrement augmenté jusqu'au vingtième jour, mais elle a fortement diminué après (40 et 60) jours de stockage par rapport au niveau de départ. La perte de poids des dates et le taux de fruits au stade rutab ont été progressivement augmentés pendant le stockage. Il y a eu des interactions significatives entre les régulateurs de croissance et la période de stockage sur la concentration en SST et en vitamine C, ainsi que sur le taux de perte de poids et sur celui de fruits au stade rutab.
This study was carried out to investigate the effect of elemental sulfur (S0) and sulfur oxidizin... more This study was carried out to investigate the effect of elemental sulfur (S0) and sulfur oxidizing bacteria (Paracoccus versutus) on nutrient uptake, yield and quality of cucumber grown in sandy calcareous soils. Both elemental sulfur powder (S0P) and pellets of sulfur powder-Tiger 90 (S0T) were applied at rates of 0, 1, 5 and 10 t/ha at Al Hamraneya. On the contrary, S0P was used at rates of 0, 1, 5 and 10 t/ha combined with or without Paracoccus versutus (Pv) at Al Kuwaitat, United Arab Emirates (UAE). Higher ...
This article appeared in a journal published by Elsevier. The attached copy is furnished to the a... more This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues. Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. In most cases authors are permitted to post their version of the article (e.g. in Word or Tex form) to their personal website or institutional repository. Authors requiring further information regarding Elsevier's archiving and manuscript policies are encouraged to visit: http://www.elsevier.com/copyright
Apples are important dietary sources of potentially healthy phenolics. In three successive season... more Apples are important dietary sources of potentially healthy phenolics. In three successive seasons, the changes in concentrations of flavonoids and chlorogenic acid in the skin of two apple cultivars 'Jonagold' and 'Elstar' during and after regular (RS) and ultra low oxygen storage (ULO) at 1°C, were quantified by reversed-phase high performance liquid chromatography (RP-HPLC) with UV-VIS detector. There were no significant differences in the concentrations of flavonoids and chlorogenic acid between fruits stored under ULO and RS conditions. During storage of both 'Jonagold' (3, 6 and 8 months) and of 'Elstar' (2, 4 and 6 months), and during 1 or 2 weeks shelf life, the concentrations of cyanidin 3-galactoside and quercetin glycosides were relatively constant, while the concentrations of catechins, phloridzin and chlorogenic acid showed only minor changes. Exposing 'Jonagold' and 'Elstar apples' to white light during shelf life following storage increased the concentration of cyanidin 3-galactoside but not any of the other flavonoid classes. An explanation for this might be that the synthesis of different flavonoid classes may have different spectral sensitivity characteristics. It is concluded that flavonoids present in apples are stable and possibly not subject to net metabolic turnover during storage and shelf life.
A field experiment was conducted in the western part of Saudi Arabia to optimize irrigation water... more A field experiment was conducted in the western part of Saudi Arabia to optimize irrigation water use (IWU), yields and quality of the 'Nabbut-Saif' date palm grown in sandy loam soil under arid conditions. Four water regimes were investigated. The supplied amounts of irrigation water were 50, 65, 82 and 100% of date palm water requirements to the first (W1), second (W2), third (W3) and fourth (W4) water regimes, respectively. The daily water requirement was calculated using the Penman-Montieth equation for dry climates and applied to the trees three times a week through a drip irrigation system. Results indicated that giving 65% of total date palm water requirement maximized date yield by producing 46.1 kg per tree and resulted in the best IWU (0.8 m 3 kg À1 per tree). Increasing the water regime to 82 and 100% of total water requirement produced only 45.5 and 46 kg per tree respectively and reduced IWU. Generally, fruit quality characteristics were insignificantly affected by the water regimes investigated. The results suggested that supplying 34 m 3 yr À1 per tree for date palms grown under the conditions of the western part of Saudi Arabia is enough to maximize IWU, yield and quality of the 'Nabbut-Saif' date palm cultivar.
There is a high demand for date palm plantlets regenerated via tissue culture techniques. However... more There is a high demand for date palm plantlets regenerated via tissue culture techniques. However, such plantlets require a long acclimatization period extending 12-18 months before transplanting in the open field. The effect of foliar and soil application of antistress substances and elemental sulphur, respectively, on growth and survival percentage of tissue culture-derived 'Khalas' date palm plantlets during acclimatization were studied. The results showed that application of salicylic acid, acetyl salicylic acid (aspirin), elemental sulphur, plantacur-E (a vitamin E formulation containing 25% α-tocopherol) at 1%, and oleic acid at 100 ppm, significantly increased plantlet survival percentages compared to the control. In this respect, gamma aminobutyric acid (GABA) at 20 mM was the most effective treatment compared to 10 mM and the control. Salicylic acid, aspirin, elemental sulphur and plantacur-E (at 2%) significantly increased the concentrations of Fe, Mn, Zn, and Cu in leaflets compared to the control. However, the macro nutrients showed no clear response to the applied treatments. Application of 250 ppm of the ethylene biosynthesis blocker, ABG-3168 (ABG), inhibited the growth of plantlets, and completely suppressed growth at 500 ppm, suggesting the potential role of ethylene biosynthesis in subsequent plantlet development. Irrigation with 10,000 ppm sea water for two months decreased chlorophyll concentration and increased electrolyte leakage by 2-3 fold compared to the control and the other treatments. GABA at 20 mM significantly increased chlorophyll concentration and decreased electrolyte leakage of leaflets compared to all the saline water treatments. In contrast, ABG at 250 ppm significantly decreased chlorophyll concentration and increased electrolyte leakage of leaflets by about 3-fold compared to all the saline water treatments. These results show potential role of GABA, salicylic acid, aspirin and oleic acid conducive for improved survival percentage of plantlets and stress tolerance during acclimatization.
Pollination and thinning are critical processes in the date palm production chain that affect fru... more Pollination and thinning are critical processes in the date palm production chain that affect fruit development, quality and yield and regulate tree yearly bearing. Developing a pollination technique that results in an acceptable level of fruit set with a minimum amount of pollen grains and without a further need for thinning is critically required for date palm production, especially under arid conditions. During 2006 and 2007 seasons, the effect of pollen grains-water suspension application at different concentrations on fruit set, yield and quality were examined on 'Lulu' date palm cultivar growing under Al-Ain oasis conditions, UAE. The results showed that pollen grains-water suspension (PGWS) application at 0.5, 1, 1.5 g/l gave fruit set percentage of 75.6, 86.8, and 87.8%, respectively which was lower than control (90.0%),traditionally pollinated). As the mean of both seasons, the PGWS application especially at 0.5 and 1.0g/l significantly decreased both bunch weight (5.52, 6.21, 7.19 and 8.54 kg for 0.5, 1.0, 1.5g/l and control, respectively) and total yield per tree (49.71, 55.92, 64.74 and 76.89 Kg/tree, for 0.5, 1.0, 1.5g/l and control, respectively) at the Tamer stage. Fruit quality characteristics especially fruit and flesh weight, length and diameter, TSS and dry matter concentration were slightly but significantly increased by the PGWS application treatments during the 2006 season. However, seed weight, acidity and vitamin C concentration were not affected by any of the pollination treatments. More research work is required for such pollination technique to justify the concentration of grains-water suspension and the response of each date palm cultivars to this pollination technique.
'Helali' is a late season date palm cultivar. At the mature (Bisir) stage, the fruit are astringe... more 'Helali' is a late season date palm cultivar. At the mature (Bisir) stage, the fruit are astringent as a result of high contents of soluble tannins, and removal of tannins is necessary for the fruit to be edible. During the harvesting season, only 30–40% of the total fruit might normally ripen (Rutab stage) on the tree and the remaining fruit fail to ripen. This study showed that bunch bagging with different materials such as black or blue polyethylene bags, white 'agrlsafe' (polypropylene fleece) and paper bags during the growing season significantly increased the rate of fruit ripening and increased Rutab yield per bunch. In this respect, black and blue polyethylene bags were the most effective followed by 'agrlsafe' and paper bags. Preharvest ethrel application significantly increased Rutab fruit yield per bunch compared to the controls. There were no significant differences in Rutab yield per bunch between sprays or injection of ethrel into the bunch peduncle. Postharvest dipping of fruit at the Bisir stage in ethrel at 4.2 ml/l and abscisic acid at 1.0 mM significantly enhanced ripening, compared to the controls. However, ABG-3168 (an ethylene blocker) application at 3.33 g/l significantly inhibited ripening, suggesting a role for ethylene in the ripening process. Ethanol vapor significantly hastened ripening of Bisir fruit over 10 days at ambient conditions in desiccators. The response of immature fruit (according to fruit density and TSS) to ethanol vapor was much greater than mature ones. Also, immersion of fruit in water for 10 h significantly increased fruit ripening compared to the controls, but to a lesser extent. It is concluded that 'Helali' date ripening could be hastened by bunch bagging during growth, or by exposing the Bisir fruit to ethanol vapor following harvest. Neither treatment showed any negative impact on the overall quality characteristics of ripe fruit, suggesting that they may be practical tools for increasing the ripening rate of Bisir 'Helali' dates.
Flower or fruit thinning is a critical cultural practice in the date palm production chain that a... more Flower or fruit thinning is a critical cultural practice in the date palm production chain that affects fruit development, quality and yield and regulates tree yearly bearing. Development of a save and economic thinning agent for date palm is critically required especially under harsh conditions. During 2004 and 2005 seasons, water spray for 3 min was applied at different times following mechanical pollination on 'Lulu' date palm cultivar growing under Al-Ain oasis conditions. The results showed that water spray following pollination generally decreased fruit set percentage to different extent depending of the time of application. In this respect, the most effective treatment was water spray after 4 h following pollination. This treatment significantly decreased fruit set percentage (48%) compared to the control (79%), as the mean of both seasons. However, the other treatments including water spray 1 h before pollination also decreased fruit set percentage but to a lesser extent. Fruit quality characteristics especially fruit and flesh weight, length and diameter were significantly increased by water spray treatments during the 2004 season, in contrast to the 2005 season. Thinning with water significantly decreased both bunch weight and total yield per tree at the Tamr stage especially when applied after 4 h following pollination. To the best of our knowledge, this is a pioneer study investigating the role of water as a potential thinning agent for date palm flowers. The use of water spray as a save and economic thinner needs, however, more research work to justify the time following pollination and duration of application which may vary upon cultivar, method of pollination and district.
There is a special interest in date palm plants regenerated by tissue culture. However, one of th... more There is a special interest in date palm plants regenerated by tissue culture. However, one of the major weaknesses of mass tissue culture propagation is the appearance of undesired off-type plants, such as poor fertility and delayed flowering. During the 2004 and 2005 seasons, the effect of five date palm pollinators, namely 'Ahmar', 'Akhdar', 'Fard', 'Khenizy' and 'Maghool' as well as sugar palm (Phoenix sylvestris), each with five different pollination densities (10, 20, 30, 40 or 50 strands/female spathe), was studied on fruit set, multi-carpel fruit formation, fruit drop, and fruit quality of eight-year tissue culture derived 'Nabt Saif' palm trees growing at Al-Ain oasis, United Arab Emirates, The results showed different degrees of compatibility among the pollinators on 'Nabt Saif'. The pollinator 'Khenizy' resulted in the highest (34.3% and 28.7%, for 2004 and 2005, respectively) and 'Fard' the lowest (11. 7% and 20 % for 2004 and 2005, respectively) fruit set level. The pollinator 'Sugar palm' (Phoenix sylvestris) was as effective as or better than the other pollinators that belong to the species Phoenix dactlifera. There were no significant differences between the different pollination densities on fruit set and fruit quality during both seasons. Generally, neither the pollinators nor the pollination density resulted in a satisfactory level of fruit set. These results may suggest that other endogenous factors are responsible for such abnormality in the tissue culture derived 'Nabt Saif' palms. Some metaxenia effects of the different pollinators on fruit quality characteristics were recorded both at Bisir and Tamr stages. In this respect, the 'Sugar palm' pollinator significantly increased fruit and flesh weight, fruit length and diameter and seed weight percentages at Bisir stage, but decreased the concentration of total soluble solids, acidity and vitamin C at both Bisir and Tamr stages compared to other pollinators. More research work is needed on tissue culture derived date palms to understand more clearly the nature of abnormalities that appear in some cultivars.
Apples are important dietary sources of potentially healthy phenolics. In three successive season... more Apples are important dietary sources of potentially healthy phenolics. In three successive seasons, the changes in concentrations of flavonoids and chlorogenic acid in the skin of two apple cultivars 'Jonagold' and 'Elstar' during and after regular (RS) and ultra low oxygen storage (ULO) at 1°C, were quantified by reversed-phase high performance liquid chromatography (RP-HPLC) with UV-VIS detector. There were no significant differences in the concentrations of flavonoids and chlorogenic acid between fruits stored under ULO and RS conditions. During storage of both 'Jonagold' (3, 6 and 8 months) and of 'Elstar' (2, 4 and 6 months), and during 1 or 2 weeks shelf life, the concentrations of cyanidin 3-galactoside and quercetin glycosides were relatively constant, while the concentrations of catechins, phloridzin and chlorogenic acid showed only minor changes. Exposing 'Jonagold' and 'Elstar apples' to white light during shelf life following storage increased the concentration of cyanidin 3-galactoside but not any of the other flavonoid classes. An explanation for this might be that the synthesis of different flavonoid classes may have different spectral sensitivity characteristics. It is concluded that flavonoids present in apples are stable and possibly not subject to net metabolic turnover during storage and shelf life.
The effect of postharvest chitosan, gallic acid (GA) and chitosan gallate (CG) dipping treatments... more The effect of postharvest chitosan, gallic acid (GA) and chitosan gallate (CG) dipping treatments at different concentrations on quality parameters, antioxidant compounds, free radical scavenging capacity (FRSC) and enzymes activities of 'Sukkari' bananas were studied during storage (ripening) at 20 ± 2 °C and 60-70% RH for 13 days. Weight loss and peel color index (the change from green to yellow) increased while, membrane stability index of peel tissues, pulp firmness and acidity decreased during storage. CG and GA treatments slowed down the changes in these parameters compared to control. Total soluble solids (TSS) concentration increased during storage and was lower at CG than other treatments. TSS/acid ratio increased during storage and showed higher value after storage than initial. This ratio was lower at 1% chitosan, 0.075% GA and CG treatments than control. Both vitamin C and total flavonoids concentrations decreased during storage and were not affected by the appli...
Effects of chitosan (1%), trans-resveratrol (resveratrol) (1.6 × 10 −5 M, 1.6 × 10 −4 M and 1.6 ×... more Effects of chitosan (1%), trans-resveratrol (resveratrol) (1.6 × 10 −5 M, 1.6 × 10 −4 M and 1.6 × 10 −3 M) and glycine betaine (GB) (10, 15 and 20 mM) dipping on quality and biochemical changes of 'Hindi-Besennara' mangoes during ripening at shelf life (SL) (18± 2 • C, 60-70% RH) were studied. Resveratrol, especially at low rate followed by GB, especially at high rate, decreased decay percentage after one and two weeks of SL compared to other treatments. Both compounds at all rates retained higher fruit firmness during SL and higher titratable acidity (TA) (only after one week of SL). Both GB and resveratrol at all rates retained higher vitamin C level than control with no effect on total soluble solids (TSS) after two weeks of SL. These compounds had no effect on weight loss after one week, but increased it after two weeks of SL compared to control. Chitosan showed higher weight loss during SL but, retained higher TA and vitamin C, and lower pH with no significant impact on firmness, TSS and decay compared to control. Chitosan, low and medium resveratrol rates, and low and high GB rates maintained higher membrane stability of peel after two weeks of SL compared to control. All treatments showed lower ␣-amylase but, higher peroxidase (POD) activities in peel than control after two weeks of SL. High resveratrol rate retained higher total phenols level than control, in contrast to chitosan after two weeks of SL while, total flavonoids was not affected. Compared to initial, peel free radical scavenging capacity (FRSC) decreased after one week followed by a sharp increase after two weeks of SL. Chitosan, medium and high resveratrol rates, and medium GB rate showed higher FRSC than control after one week of SL but, with no differences after two weeks of SL. In conclusion, both trans-resveratrol and GB treatments retained quality of 'Hindi-Besennara' mangoes during SL and being suggested as natural alternatives to synthetic chemicals.
A field experiment was conducted in 2011 and 2012 to study the effect of fertigation on yield, fr... more A field experiment was conducted in 2011 and 2012 to study the effect of fertigation on yield, fruit quality and nutrient uptake of 'Nabbut-Ahmar' date palm cultivar grown in sandy loam soil. Three fertigation treatments were compared with traditional application. In traditional treatment (CT), the recommended dose [2300 g nitrogen (N), 1200 g phosphorus (P) and 1400 g/ tree] was applied as a soil broadcast in three equal doses. The fertigation treatments, (T2), (T3) and (T4), represent all nitrogen, phosphorus and potassium (NPK) amounts of CT, 2/3 CT and 1/3 CT, respectively that were injected in twelve equal doses. The results showed that compared to CT, the fertigation treatments increased yield/palm by 41%, 31% and 18% for T3, T2 and T4, respectively. Beside the increase in yield, 33% and 66% of the applied fertilizers were saved by T3 and T4, respectively, compared with CT. Feritgation treatments had no negative impact on the overall fruit quality characteristics and even increased total soluble solids (TSS), soluble tannins and total phenols concentrations compared to the conventional fertilization. Availability of NPK increased by fertigation but without further increase in leaves and fruit. In conclusion applying 2/3 of the recommended dose of NPK fertilizers under dry land condition through fertigation maximize yield, quality and fertilizer use efficiency.
Biochemical changes in fruit of an early and a late date palm cultivar during development and rip... more Biochemical changes in fruit of an early and a late date palm cultivar during development and ripening (2011) International Journal of Fruit Science, 11 (2), pp. 167-183. Cited 1 time.
Effects of chitosan (1%), trans-resveratrol (resveratrol) (1.6 × 10 −5 M, 1.6 × 10 −4 M and 1.6 ×... more Effects of chitosan (1%), trans-resveratrol (resveratrol) (1.6 × 10 −5 M, 1.6 × 10 −4 M and 1.6 × 10 −3 M) and glycine betaine (GB) (10, 15 and 20 mM) dipping on quality and biochemical changes of 'Hindi-Besennara' mangoes during ripening at shelf life (SL) (18± 2 • C, 60-70% RH) were studied. Resveratrol, especially at low rate followed by GB, especially at high rate, decreased decay percentage after one and two weeks of SL compared to other treatments. Both compounds at all rates retained higher fruit firmness during SL and higher titratable acidity (TA) (only after one week of SL). Both GB and resveratrol at all rates retained higher vitamin C level than control with no effect on total soluble solids (TSS) after two weeks of SL. These compounds had no effect on weight loss after one week, but increased it after two weeks of SL compared to control. Chitosan showed higher weight loss during SL but, retained higher TA and vitamin C, and lower pH with no significant impact on firmness, TSS and decay compared to control. Chitosan, low and medium resveratrol rates, and low and high GB rates maintained higher membrane stability of peel after two weeks of SL compared to control. All treatments showed lower ␣-amylase but, higher peroxidase (POD) activities in peel than control after two weeks of SL. High resveratrol rate retained higher total phenols level than control, in contrast to chitosan after two weeks of SL while, total flavonoids was not affected. Compared to initial, peel free radical scavenging capacity (FRSC) decreased after one week followed by a sharp increase after two weeks of SL. Chitosan, medium and high resveratrol rates, and medium GB rate showed higher FRSC than control after one week of SL but, with no differences after two weeks of SL. In conclusion, both trans-resveratrol and GB treatments retained quality of 'Hindi-Besennara' mangoes during SL and being suggested as natural alternatives to synthetic chemicals.
Talh trees (Acacia gerrardii Benth.) are acacias that are native to the arid and semiarid Africa ... more Talh trees (Acacia gerrardii Benth.) are acacias that are native to the arid and semiarid Africa and west Asia. We investigated the flowering biology, pod set and flower visitors of Talh and discussed the role of these visitors in pollen transfer. The Talh trees blossomed laterally on the nodes of one-year-old twigs. Each node produced 21 flower buds seasonally. Each flower bud opened to a flower head (FH) of 60 florets. The bagged FHs podded significantly (p 6 0.05) less than did the unbagged FHs. The FHs were visited by 31 insect species (25 genera, 16 families and 5 orders). The major taxa were honeybees, megachilids, butterflies, ants, beetles and thrips. Each of honeybees, megachilids and beetles showed a significant (p 6 0.05) hourly pattern, while each of butterflies, ants and thrips had no hourly pattern (p > 0.05). Furthermore, some birds and mammals touched the Talh FHs. Talh trees evolved a mass flowering behavior to face preand post-flowering obstacles. Megachilids seemed to play the major effort of zoophily because of their relatively high numbers of individuals and species and their effective movement behavior on the FH surface. Nevertheless, honeybees and other insects and vertebrate taxa also contributed to the pollen transfer. These results greatly contribute to our understanding of the pollination ecology of acacias, especially Arabian acacias.
Potassium (K) is a critical element for date palm production especially under stress conditions. ... more Potassium (K) is a critical element for date palm production especially under stress conditions. During 2011 and 2012 seasons, two methods of K fertilization (K2SO4, 52% K2O) at different rates were evaluated on ‘Seweda’ date palm cultivar. The first method was soil broadcast (SB) of 2, 3 and 4 kg/palm in 3 equal doses (February, April and May). While in the second method, half of these amounts were applied as SB and the other half as foliar spray (FS) in 10 equal doses during growing season. The results showed no significant effect of K fertilization on either bunch weight or yield as the mean of two seasons. However, in 2012, the highest bunch weight and yield was at the 2 kg SB + 2 kg FS treatment while, the lowest values were at the 2 kg SB treatment. The highest rutab % obtained from the 2 kg SB treatment. Both fruit and flesh weight at the bisir stage were higher at the high rates of K applied as SB + FS than SB. Also, K concentration of leaves was higher in SB + FS than SB. K...
Variations in¯avonoid and chlorogenic acid levels within fruit, within tree, between orchards, be... more Variations in¯avonoid and chlorogenic acid levels within fruit, within tree, between orchards, between cultivars and among mutants were characterised and quanti®ed in`Elstar' and`Jonagold' apples by reversed-phase high performance liquid chromatography (RP-HPLC). The sun-exposed skin of individual fruit had much higher cyanidin 3-galactoside (anthocyanin) and quercetin 3glycoside levels than the shaded skin, while phloridzin, catechins and chlorogenic acid were similar in the skin of both sides. Individual¯avonoid and chlorogenic acid levels were not equally distributed within the fruit. Quercetin 3-glycosides and anthocyanin were almost exclusively found in the skin. Catechins were mostly found in the skin but some were present in the¯esh. Phloridzin was most abundant in the seeds, with intermediate levels in both the core area and the skin, and the lowest level in the¯esh. Chlorogenic acid was mainly present in the core area and the seeds with an intermediate level in the¯esh and a low level in the skin. The levels of anthocyanin, quercetin 3glycosides and total¯avonoids were highest in fruit borne in the top of the tree followed by fruit from the outer tree parts, whereas the lowest levels were found in fruit from the inner tree. Terminal fruit contained the highest levels of these compounds, including catechins, compared to lateral and spur fruit. Phloridzin and chlorogenic acid were not affected by the position of the fruit in the tree nor by the bearing wood type. There were large differences in¯avonoid and chlorogenic acid levels in`Elstar' fruit between two normally productive orchards differing mainly in growth vigour. Jonagold' and its mutants had considerably higher levels of¯avonoid and chlorogenic acid thaǹ Elstar' and its mutants. The most blushed mutants of both cultivars had higher levels of anthocyanin but not of¯avonoids or chlorogenic acid compared to the standard cultivar and to the less blushed mutants. The most blushed mutants had a higher number of red cells per cell layer and Scientia Horticulturae 83 (2000) 249±263
Quality characteristics of bisir 'Barhee' dates during cold storage as affected by postharvest di... more Quality characteristics of bisir 'Barhee' dates during cold storage as affected by postharvest dipping in gibberellic acid, naphthaleneacetic acid and benzyladenine. Abstract-Introduction. There is a growing demand in the international market for excellent-quality dates of cultivars such as 'Barhee' that are consumed at the bisir stage. Materials and methods. The effects of GA 3 , BA and NAA postharvest dipping treatments at different concentrations on the quality characteristics of bisir 'Barhee' dates during cold storage were investigated. Results and discussion. The total soluble solids (TSS) concentration was lower in the BA-and NAA-treated fruit than in control fruit. Similarly, the GA 3-treated fruit at 150 mg•L-1 contained a lower TSS concentration than control fruit. The GA 3 at 150 mg•L-1 , BA at 60 mg•L-1 and NAA at (100 and 150) mg•L-1 increased vitamin C concentration compared with other treatments. Acidity and total phenol concentrations were not affected by any of the treatments. The date soluble tannin concentration was higher than control fruit only in the dates treated with 20 mg BA•L-1. The weight loss % was lower in the BA-treated fruit at (20 and 60) mg•L-1 compared with all other treatments, while GA 3 treatment at 50 mg•L-1 increased fruit weight loss % compared with control fruit. The percentage of dates at the rutab stage (index for fruit ripening) was lower for fruit treated with GA 3 than for control fruit. Also, the rutab stage % was lower for fruit treated with BA at 40 mg•L-1 and NAA at 150 mg•L-1 compared with control fruit. The TSS concentration decreased during storage from the initial day to day 20. However, there were no further decreases in the TSS concentration after (40 and 60) days of storage. The acidity concentration was slightly increased during storage. The vitamin C concentration increased until 40 days of storage, then a slight decrease occurred. The total phenol concentration decreased after (40 and 60) days of storage compared with the initial level. The soluble tannin concentration slightly increased at day 20 but sharply decreased after (40 and 60) days of storage compared with the initial level. Both weight loss and rutab stage % gradually increased during storage. There were significant interaction effects between growth regulators and storage period on TSS, vitamin C concentration, weight loss and rutab stage %. Saudi Arabia / Phoenix dactylifera / fruits / developmental stages / cold storage / quality / chemicophysical properties / ripening / maturity Qualité des dates 'Barhee' au stade bisir stockées au froid après trempage post récolte dans l'acide gibbérellique, l'acide naphtalène et la benzyladénine. Résumé-Introduction. Il existe une demande croissante dans le marché international pour des dates d'excellente qualité telles que le sont celles du cultivar 'Barhee' qui sont consommées au stade bisir. Matériel et méthodes. Les effets du traitement de dates 'Barhee' au stade bisir par trempage après récolte dans des solutions de GA 3 , BA et ANA à différentes concentrations ont été étudiés sur certaines caractéristiques de qualité des fruits pendant leur stockage au froid. Résultats et discussion. La concentration en solubles solides totaux (SST) dans les fruits traités avec BA et NAA a été plus faible que dans les fruits témoins. De même, les fruits traités avec 150 mg GA 3 •L-1 ont montré une concentration de SST plus faible que les fruits témoins. Les traitements avec 150 mg GA 3 •L-1 , 60 mg BA•L-1 et (100 et 150) mg NAA•L-1 ont augmenté la concentration en vitamine C des dates par rapport aux autres traitements. L'acidité et la concentration en phénols totaux n'ont été affectés par aucun des traitements. La concentration en tanins solubles des dates traitées ne s'est révélée plus élevée que celle des fruits témoins que dans les fruits traités avec 20 mg BA•L-1. La perte de poids des fruits traités avec (20 et 60) mg BA•L-1 a été inférieure à celle des fruits de tous les autres traitements, tandis que le traitement à 50 mg GA 3 •L-1 a augmenté la perte de poids des dates par rapport aux fruits témoins. Le pourcentage de dates au stade rutab (indice de maturation des fruits) a été plus faible pour les fruits traités avec GA 3 que pour les fruits témoins. En outre, ce pourcentage a été plus faible pour les fruits traités avec 40 mg BA•L-1 et 150 mg NAA•L-1 que pour les fruits témoins. La concentration en SST a diminué du premier au vingtième jour de stockage. Cependant, il n'y a pas eu de nouvelles baisses de cette concentration après (40 et 60) jours de stockage. L'acidité a été légèrement augmentée durant le stockage. La concentration en vitamine C a augmenté jusqu'à 40 jours de stockage, puis une légère baisse s'est produite. La concentration totale en phénols a diminué après (40 et 60) jours de stockage par rapport au niveau de départ. La concentration des tanins solubles a légèrement augmenté jusqu'au vingtième jour, mais elle a fortement diminué après (40 et 60) jours de stockage par rapport au niveau de départ. La perte de poids des dates et le taux de fruits au stade rutab ont été progressivement augmentés pendant le stockage. Il y a eu des interactions significatives entre les régulateurs de croissance et la période de stockage sur la concentration en SST et en vitamine C, ainsi que sur le taux de perte de poids et sur celui de fruits au stade rutab.
This study was carried out to investigate the effect of elemental sulfur (S0) and sulfur oxidizin... more This study was carried out to investigate the effect of elemental sulfur (S0) and sulfur oxidizing bacteria (Paracoccus versutus) on nutrient uptake, yield and quality of cucumber grown in sandy calcareous soils. Both elemental sulfur powder (S0P) and pellets of sulfur powder-Tiger 90 (S0T) were applied at rates of 0, 1, 5 and 10 t/ha at Al Hamraneya. On the contrary, S0P was used at rates of 0, 1, 5 and 10 t/ha combined with or without Paracoccus versutus (Pv) at Al Kuwaitat, United Arab Emirates (UAE). Higher ...
This article appeared in a journal published by Elsevier. The attached copy is furnished to the a... more This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues. Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. In most cases authors are permitted to post their version of the article (e.g. in Word or Tex form) to their personal website or institutional repository. Authors requiring further information regarding Elsevier's archiving and manuscript policies are encouraged to visit: http://www.elsevier.com/copyright
Apples are important dietary sources of potentially healthy phenolics. In three successive season... more Apples are important dietary sources of potentially healthy phenolics. In three successive seasons, the changes in concentrations of flavonoids and chlorogenic acid in the skin of two apple cultivars 'Jonagold' and 'Elstar' during and after regular (RS) and ultra low oxygen storage (ULO) at 1°C, were quantified by reversed-phase high performance liquid chromatography (RP-HPLC) with UV-VIS detector. There were no significant differences in the concentrations of flavonoids and chlorogenic acid between fruits stored under ULO and RS conditions. During storage of both 'Jonagold' (3, 6 and 8 months) and of 'Elstar' (2, 4 and 6 months), and during 1 or 2 weeks shelf life, the concentrations of cyanidin 3-galactoside and quercetin glycosides were relatively constant, while the concentrations of catechins, phloridzin and chlorogenic acid showed only minor changes. Exposing 'Jonagold' and 'Elstar apples' to white light during shelf life following storage increased the concentration of cyanidin 3-galactoside but not any of the other flavonoid classes. An explanation for this might be that the synthesis of different flavonoid classes may have different spectral sensitivity characteristics. It is concluded that flavonoids present in apples are stable and possibly not subject to net metabolic turnover during storage and shelf life.
A field experiment was conducted in the western part of Saudi Arabia to optimize irrigation water... more A field experiment was conducted in the western part of Saudi Arabia to optimize irrigation water use (IWU), yields and quality of the 'Nabbut-Saif' date palm grown in sandy loam soil under arid conditions. Four water regimes were investigated. The supplied amounts of irrigation water were 50, 65, 82 and 100% of date palm water requirements to the first (W1), second (W2), third (W3) and fourth (W4) water regimes, respectively. The daily water requirement was calculated using the Penman-Montieth equation for dry climates and applied to the trees three times a week through a drip irrigation system. Results indicated that giving 65% of total date palm water requirement maximized date yield by producing 46.1 kg per tree and resulted in the best IWU (0.8 m 3 kg À1 per tree). Increasing the water regime to 82 and 100% of total water requirement produced only 45.5 and 46 kg per tree respectively and reduced IWU. Generally, fruit quality characteristics were insignificantly affected by the water regimes investigated. The results suggested that supplying 34 m 3 yr À1 per tree for date palms grown under the conditions of the western part of Saudi Arabia is enough to maximize IWU, yield and quality of the 'Nabbut-Saif' date palm cultivar.
There is a high demand for date palm plantlets regenerated via tissue culture techniques. However... more There is a high demand for date palm plantlets regenerated via tissue culture techniques. However, such plantlets require a long acclimatization period extending 12-18 months before transplanting in the open field. The effect of foliar and soil application of antistress substances and elemental sulphur, respectively, on growth and survival percentage of tissue culture-derived 'Khalas' date palm plantlets during acclimatization were studied. The results showed that application of salicylic acid, acetyl salicylic acid (aspirin), elemental sulphur, plantacur-E (a vitamin E formulation containing 25% α-tocopherol) at 1%, and oleic acid at 100 ppm, significantly increased plantlet survival percentages compared to the control. In this respect, gamma aminobutyric acid (GABA) at 20 mM was the most effective treatment compared to 10 mM and the control. Salicylic acid, aspirin, elemental sulphur and plantacur-E (at 2%) significantly increased the concentrations of Fe, Mn, Zn, and Cu in leaflets compared to the control. However, the macro nutrients showed no clear response to the applied treatments. Application of 250 ppm of the ethylene biosynthesis blocker, ABG-3168 (ABG), inhibited the growth of plantlets, and completely suppressed growth at 500 ppm, suggesting the potential role of ethylene biosynthesis in subsequent plantlet development. Irrigation with 10,000 ppm sea water for two months decreased chlorophyll concentration and increased electrolyte leakage by 2-3 fold compared to the control and the other treatments. GABA at 20 mM significantly increased chlorophyll concentration and decreased electrolyte leakage of leaflets compared to all the saline water treatments. In contrast, ABG at 250 ppm significantly decreased chlorophyll concentration and increased electrolyte leakage of leaflets by about 3-fold compared to all the saline water treatments. These results show potential role of GABA, salicylic acid, aspirin and oleic acid conducive for improved survival percentage of plantlets and stress tolerance during acclimatization.
Pollination and thinning are critical processes in the date palm production chain that affect fru... more Pollination and thinning are critical processes in the date palm production chain that affect fruit development, quality and yield and regulate tree yearly bearing. Developing a pollination technique that results in an acceptable level of fruit set with a minimum amount of pollen grains and without a further need for thinning is critically required for date palm production, especially under arid conditions. During 2006 and 2007 seasons, the effect of pollen grains-water suspension application at different concentrations on fruit set, yield and quality were examined on 'Lulu' date palm cultivar growing under Al-Ain oasis conditions, UAE. The results showed that pollen grains-water suspension (PGWS) application at 0.5, 1, 1.5 g/l gave fruit set percentage of 75.6, 86.8, and 87.8%, respectively which was lower than control (90.0%),traditionally pollinated). As the mean of both seasons, the PGWS application especially at 0.5 and 1.0g/l significantly decreased both bunch weight (5.52, 6.21, 7.19 and 8.54 kg for 0.5, 1.0, 1.5g/l and control, respectively) and total yield per tree (49.71, 55.92, 64.74 and 76.89 Kg/tree, for 0.5, 1.0, 1.5g/l and control, respectively) at the Tamer stage. Fruit quality characteristics especially fruit and flesh weight, length and diameter, TSS and dry matter concentration were slightly but significantly increased by the PGWS application treatments during the 2006 season. However, seed weight, acidity and vitamin C concentration were not affected by any of the pollination treatments. More research work is required for such pollination technique to justify the concentration of grains-water suspension and the response of each date palm cultivars to this pollination technique.
'Helali' is a late season date palm cultivar. At the mature (Bisir) stage, the fruit are astringe... more 'Helali' is a late season date palm cultivar. At the mature (Bisir) stage, the fruit are astringent as a result of high contents of soluble tannins, and removal of tannins is necessary for the fruit to be edible. During the harvesting season, only 30–40% of the total fruit might normally ripen (Rutab stage) on the tree and the remaining fruit fail to ripen. This study showed that bunch bagging with different materials such as black or blue polyethylene bags, white 'agrlsafe' (polypropylene fleece) and paper bags during the growing season significantly increased the rate of fruit ripening and increased Rutab yield per bunch. In this respect, black and blue polyethylene bags were the most effective followed by 'agrlsafe' and paper bags. Preharvest ethrel application significantly increased Rutab fruit yield per bunch compared to the controls. There were no significant differences in Rutab yield per bunch between sprays or injection of ethrel into the bunch peduncle. Postharvest dipping of fruit at the Bisir stage in ethrel at 4.2 ml/l and abscisic acid at 1.0 mM significantly enhanced ripening, compared to the controls. However, ABG-3168 (an ethylene blocker) application at 3.33 g/l significantly inhibited ripening, suggesting a role for ethylene in the ripening process. Ethanol vapor significantly hastened ripening of Bisir fruit over 10 days at ambient conditions in desiccators. The response of immature fruit (according to fruit density and TSS) to ethanol vapor was much greater than mature ones. Also, immersion of fruit in water for 10 h significantly increased fruit ripening compared to the controls, but to a lesser extent. It is concluded that 'Helali' date ripening could be hastened by bunch bagging during growth, or by exposing the Bisir fruit to ethanol vapor following harvest. Neither treatment showed any negative impact on the overall quality characteristics of ripe fruit, suggesting that they may be practical tools for increasing the ripening rate of Bisir 'Helali' dates.
Flower or fruit thinning is a critical cultural practice in the date palm production chain that a... more Flower or fruit thinning is a critical cultural practice in the date palm production chain that affects fruit development, quality and yield and regulates tree yearly bearing. Development of a save and economic thinning agent for date palm is critically required especially under harsh conditions. During 2004 and 2005 seasons, water spray for 3 min was applied at different times following mechanical pollination on 'Lulu' date palm cultivar growing under Al-Ain oasis conditions. The results showed that water spray following pollination generally decreased fruit set percentage to different extent depending of the time of application. In this respect, the most effective treatment was water spray after 4 h following pollination. This treatment significantly decreased fruit set percentage (48%) compared to the control (79%), as the mean of both seasons. However, the other treatments including water spray 1 h before pollination also decreased fruit set percentage but to a lesser extent. Fruit quality characteristics especially fruit and flesh weight, length and diameter were significantly increased by water spray treatments during the 2004 season, in contrast to the 2005 season. Thinning with water significantly decreased both bunch weight and total yield per tree at the Tamr stage especially when applied after 4 h following pollination. To the best of our knowledge, this is a pioneer study investigating the role of water as a potential thinning agent for date palm flowers. The use of water spray as a save and economic thinner needs, however, more research work to justify the time following pollination and duration of application which may vary upon cultivar, method of pollination and district.
There is a special interest in date palm plants regenerated by tissue culture. However, one of th... more There is a special interest in date palm plants regenerated by tissue culture. However, one of the major weaknesses of mass tissue culture propagation is the appearance of undesired off-type plants, such as poor fertility and delayed flowering. During the 2004 and 2005 seasons, the effect of five date palm pollinators, namely 'Ahmar', 'Akhdar', 'Fard', 'Khenizy' and 'Maghool' as well as sugar palm (Phoenix sylvestris), each with five different pollination densities (10, 20, 30, 40 or 50 strands/female spathe), was studied on fruit set, multi-carpel fruit formation, fruit drop, and fruit quality of eight-year tissue culture derived 'Nabt Saif' palm trees growing at Al-Ain oasis, United Arab Emirates, The results showed different degrees of compatibility among the pollinators on 'Nabt Saif'. The pollinator 'Khenizy' resulted in the highest (34.3% and 28.7%, for 2004 and 2005, respectively) and 'Fard' the lowest (11. 7% and 20 % for 2004 and 2005, respectively) fruit set level. The pollinator 'Sugar palm' (Phoenix sylvestris) was as effective as or better than the other pollinators that belong to the species Phoenix dactlifera. There were no significant differences between the different pollination densities on fruit set and fruit quality during both seasons. Generally, neither the pollinators nor the pollination density resulted in a satisfactory level of fruit set. These results may suggest that other endogenous factors are responsible for such abnormality in the tissue culture derived 'Nabt Saif' palms. Some metaxenia effects of the different pollinators on fruit quality characteristics were recorded both at Bisir and Tamr stages. In this respect, the 'Sugar palm' pollinator significantly increased fruit and flesh weight, fruit length and diameter and seed weight percentages at Bisir stage, but decreased the concentration of total soluble solids, acidity and vitamin C at both Bisir and Tamr stages compared to other pollinators. More research work is needed on tissue culture derived date palms to understand more clearly the nature of abnormalities that appear in some cultivars.
Apples are important dietary sources of potentially healthy phenolics. In three successive season... more Apples are important dietary sources of potentially healthy phenolics. In three successive seasons, the changes in concentrations of flavonoids and chlorogenic acid in the skin of two apple cultivars 'Jonagold' and 'Elstar' during and after regular (RS) and ultra low oxygen storage (ULO) at 1°C, were quantified by reversed-phase high performance liquid chromatography (RP-HPLC) with UV-VIS detector. There were no significant differences in the concentrations of flavonoids and chlorogenic acid between fruits stored under ULO and RS conditions. During storage of both 'Jonagold' (3, 6 and 8 months) and of 'Elstar' (2, 4 and 6 months), and during 1 or 2 weeks shelf life, the concentrations of cyanidin 3-galactoside and quercetin glycosides were relatively constant, while the concentrations of catechins, phloridzin and chlorogenic acid showed only minor changes. Exposing 'Jonagold' and 'Elstar apples' to white light during shelf life following storage increased the concentration of cyanidin 3-galactoside but not any of the other flavonoid classes. An explanation for this might be that the synthesis of different flavonoid classes may have different spectral sensitivity characteristics. It is concluded that flavonoids present in apples are stable and possibly not subject to net metabolic turnover during storage and shelf life.
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