The chlorophyll meter (SPAD-502) is a simple, portable diagnostic tool that measures the greennes... more The chlorophyll meter (SPAD-502) is a simple, portable diagnostic tool that measures the greenness or relative content of leaves. Compared to the traditional destructive methods, the use of this equipment saves time, space and resources. The objective of this study was to establish a correlation between the photosynthetic pigments content extracted in DMSO, the total nitrogen content and the chlorophyll a fluorescence variables with the SPAD-502 readings in Coffea canephora Pierre leaves. The SPAD-502 has been shown to be a good tool to diagnose the integrity of the photosynthetic system in coffee leaves, and can thus help in the advanced interpretations of the photochemical process of these plants. The SPAD readings lower 40 show impairment in photosynthetic process. Thus, the portable chlorophyll SPAD-502 can be used to analyze the photosyn-www.elsevier.com/locate/scihorti Scientia Horticulturae 104 (2005) 199-209 Abbreviations: F 0 , minimal fluorescence; F m , maximal fluorescence; F v / F m , ratio of variable to maximal fluorescence-maximum quantum efficiency of open photosystem II centres-quantum yield; q p , photochemical quenching; q N , non-photochemical quenching; Q a , primary quinone acceptor of photosytem II; PSII, photosystem II; DMSO, dimethylsulphoxide; Chl, chlorophyll; Car, carotenoids
Plant Ecophysiology was used as a tool to interpret the responses and adaptation of pastures to e... more Plant Ecophysiology was used as a tool to interpret the responses and adaptation of pastures to environmental conditions. The objective of this study was to evaluate ecophysiological parameters in Brachiaria decumbens grown in different grazing systems in the Cerrados biome in the south state of Maranhao, Brazil. The experiment was conducted in a completely randomized design with nine replications, using a 3×2×3 factorial arrangement consisted of three grazing management systems (silvopastoral, a rotation system with regeneration of native vegetation, and extensive) two seasons (dry and rainy), and three evaluation times along the day. The photochemical efficiency, performance index, and estimation of chlorophyll content were evaluated. According to the results, most of the parameters of the variables evaluated for B. decumbens presented stress conditions, thus compromising their photosynthetic apparatus. B. decumbens presented the best photochemical efficiency and estimated chloro...
... seca de raiz e de parte aérea. Esta diminuição foi relacionada com alterações nas concentraçõ... more ... seca de raiz e de parte aérea. Esta diminuição foi relacionada com alterações nas concentrações de etileno e de ácido abscísico na seiva do xilema. A restrição radicular foi responsável pela diminuição no comprimento das folhas e raízes de pimentão (ISMAIL & DAVIES, 1998 ...
The objective of this study was to assess the physiological aspects of young green dwarf coconut ... more The objective of this study was to assess the physiological aspects of young green dwarf coconut cultivated in greenhouse as a function of soil class and different compaction levels and moisture conditions. The experiment was carried out in a greenhouse, using a randomized complete block design with nine replications and with 32 treatments in a 2 × 4 × 4 factorial scheme, with two soil classes—Typic Kandiudult and Umbric Dystrochrept, four compaction levels and four soil moisture conditions. Leaf predawn water potential (Ψw), net photosynthetic (A), stomatal conductance (gs), transpiration rates (E) and growth traits were higher in coconut grown in Umbric Dystrochrept soil. Moreover, these plants showed the highest values of maximum quantum yield of photosystem II (Fv/Fm) and leaf ‘greenness' (SPAD reading) was higher, but only in the lowest soil moisture condition, when compared with Typic Kandiudult. Higher soil moisture led to a higher Ψw for both soil classes. Close relationship between SPAD reading and the increase in soil moisture as well as between Fv/Fm and the increase in soil moisture for coconuts grown in Typic Kandiudult soil was observed. Furthermore, good correlations were observed between Ψw and the increase in soil moisture in coconuts grown in both soil classes as well as between Fv/Fm and the increase in soil density in coconuts grown in Typic Kandiudult soil. Effects of soil compaction were not observed on other physiological variables. Overall, green dwarf coconut trees grown in Umbric Dystrochrept soil allowed the higher water storage, which may contribute to increases in circumference, plant height, leaf area and dry weight (leaves, stem and root) linked to high photosynthetic rates.
RESUMO A utilização da técnica de enxertia em maracujazeiros tem sido uma estratégia promissora p... more RESUMO A utilização da técnica de enxertia em maracujazeiros tem sido uma estratégia promissora para o desenvolvimento de cultivares tradicionais de maracujazeiros que, por sua vez, apresentam raízes suscetíveis a vários patógenos do solo. Contudo, não se conhece o efeito desta técnica sobre as trocas gasosas, as relações hídricas e a eficiência fotoquímica em plantas desta espécie. O objetivo deste trabalho foi estudar a capacidade fotossintética, as relações hídricas e o crescimento de maracujazeiros propagados por semente (PPS) e propagados por enxertia (PPG), submetidos à limitação da disponibilidade de água no solo. O presente estudo foi realizado em casa de vegetação, utilizando mudas de Passiflora edulis f. flavicarpa e mudas enxertadas [Passiflora edulis f. flavicarpa (enxerto) e Passiflora mucronata (porta-enxerto)] cultivadas em potes de 3,5 dm3. Aos 37 dias após o transplantio (DAT), foi suspensa a irrigação em metade das plantas propagadas por sementes (PPSDS, plantas pr...
ABSTRACT Plantas de Coffea canephora Pierre foram cultivadas em recipientes de diferentes volumes... more ABSTRACT Plantas de Coffea canephora Pierre foram cultivadas em recipientes de diferentes volumes (50, 100, 200, 300 e 3400 mL), contendo Plantmax® como substrato. As plantas cresceram sob telado com 50% de interceptação da densidade de fluxo de fótons fotossintéticos (PPFD), sendo utilizado um sistema de irrigação do tipo nebulização intermitente. No local, foram monitoradas a temperatura, a umidade relativa do ar e a PPFD. O objetivo desse trabalho foi avaliar os efeitos de diferentes volumes de recipientes de cultivo, ao longo do tempo, sobre algumas características biométricas e sobre a taxa de assimilação de CO2. Quando comparadas com as plantas crescidas nos recipientes de 3400 mL, as que que cresceram nos recipientes de 50, 100, 200 e 300 mL apresentaram menores medidas biométricas. As diferenças foram observadas a partir da 5a semana após transplantio (SAT) para o comprimento da nervura central (CNC), da 16aSAT para a altura (H), massa seca da parte aérea (MSPA), massa seca radicular (MSR), área foliar (AF), área radicular (AR), volume radicular (VR) e da 20a SAT para número de folhas (NF). Entre as plantas de Coffea c. crescidas nos diferentes recipientes de cultivo, as diferenças encontradas nos valores das medidas biométricas estudadas parecem não estar relacionadas com a taxa fotossintética líquida, expressa por unidade de área da folha. No entanto, a síntese global de fotoassimilados foi fortemente afetada por meio do impacto no desenvolvimento.
Introduction. Papaya is one of the very few fruit crops multiplied by seed. Unfortunately, the us... more Introduction. Papaya is one of the very few fruit crops multiplied by seed. Unfortunately, the use of seedlings hampers the preservation of favorable plant characteristics and delays the appearance of the first flowers. In addition, the polygamous nature of papaya imposes planting 3-4 seedlings per hole in order to be certain of obtaining the right sex type. These shortcomings can be circumvented by clonal multiplication. This work aimed to multiply selected papaya cultivars from cuttings using the rooting promoting auxin indole-3-butyric acid (IBA). Materials and methods. Two experiments were conducted; the first one followed a completely randomized factorial design, with cultivars 'Golden' and 'Uenf/Caliman 01' as levels of the first factor, and 0, 500, 1,000, 1,500, and 2,000 ppm IBA as levels of the second factor. In this first trial, rooted cuttings of 'Uenf/Caliman 01' were taken to the field and compared to seedlings soon after planting and 4.5 months later. In the second experiment, IBA levels were increased aiming to enhance rooting percentage. Physiological assessments of rooted cuttings were also performed in this second experiment. Results and discussion. A concentration of 3,000 ppm IBA gave the best results for 'Golden', while lower concentration (1,500 ppm) seemed indicated for 'Uenf/Caliman 01'. Rooting success in 'Uenf/Caliman 01' was improved by using cuttings obtained from beheaded mother plants. The analyses showed that a few roots were sufficient to maintain good water status and photosynthetic rate in new plantlets. Conclusion. Plants propagated from cuttings had early flowering and produced first fruits at a lower height than seedlings in the field.
The chlorophyll meter (SPAD-502) is a simple, portable diagnostic tool that measures the greennes... more The chlorophyll meter (SPAD-502) is a simple, portable diagnostic tool that measures the greenness or relative content of leaves. Compared to the traditional destructive methods, the use of this equipment saves time, space and resources. The objective of this study was to establish a correlation between the photosynthetic pigments content extracted in DMSO, the total nitrogen content and the chlorophyll a fluorescence variables with the SPAD-502 readings in Coffea canephora Pierre leaves. The SPAD-502 has been shown to be a good tool to diagnose the integrity of the photosynthetic system in coffee leaves, and can thus help in the advanced interpretations of the photochemical process of these plants. The SPAD readings lower 40 show impairment in photosynthetic process. Thus, the portable chlorophyll SPAD-502 can be used to analyze the photosyn-www.elsevier.com/locate/scihorti Scientia Horticulturae 104 (2005) 199-209 Abbreviations: F 0 , minimal fluorescence; F m , maximal fluorescence; F v / F m , ratio of variable to maximal fluorescence-maximum quantum efficiency of open photosystem II centres-quantum yield; q p , photochemical quenching; q N , non-photochemical quenching; Q a , primary quinone acceptor of photosytem II; PSII, photosystem II; DMSO, dimethylsulphoxide; Chl, chlorophyll; Car, carotenoids
Plant Ecophysiology was used as a tool to interpret the responses and adaptation of pastures to e... more Plant Ecophysiology was used as a tool to interpret the responses and adaptation of pastures to environmental conditions. The objective of this study was to evaluate ecophysiological parameters in Brachiaria decumbens grown in different grazing systems in the Cerrados biome in the south state of Maranhao, Brazil. The experiment was conducted in a completely randomized design with nine replications, using a 3×2×3 factorial arrangement consisted of three grazing management systems (silvopastoral, a rotation system with regeneration of native vegetation, and extensive) two seasons (dry and rainy), and three evaluation times along the day. The photochemical efficiency, performance index, and estimation of chlorophyll content were evaluated. According to the results, most of the parameters of the variables evaluated for B. decumbens presented stress conditions, thus compromising their photosynthetic apparatus. B. decumbens presented the best photochemical efficiency and estimated chloro...
... seca de raiz e de parte aérea. Esta diminuição foi relacionada com alterações nas concentraçõ... more ... seca de raiz e de parte aérea. Esta diminuição foi relacionada com alterações nas concentrações de etileno e de ácido abscísico na seiva do xilema. A restrição radicular foi responsável pela diminuição no comprimento das folhas e raízes de pimentão (ISMAIL & DAVIES, 1998 ...
The objective of this study was to assess the physiological aspects of young green dwarf coconut ... more The objective of this study was to assess the physiological aspects of young green dwarf coconut cultivated in greenhouse as a function of soil class and different compaction levels and moisture conditions. The experiment was carried out in a greenhouse, using a randomized complete block design with nine replications and with 32 treatments in a 2 × 4 × 4 factorial scheme, with two soil classes—Typic Kandiudult and Umbric Dystrochrept, four compaction levels and four soil moisture conditions. Leaf predawn water potential (Ψw), net photosynthetic (A), stomatal conductance (gs), transpiration rates (E) and growth traits were higher in coconut grown in Umbric Dystrochrept soil. Moreover, these plants showed the highest values of maximum quantum yield of photosystem II (Fv/Fm) and leaf ‘greenness' (SPAD reading) was higher, but only in the lowest soil moisture condition, when compared with Typic Kandiudult. Higher soil moisture led to a higher Ψw for both soil classes. Close relationship between SPAD reading and the increase in soil moisture as well as between Fv/Fm and the increase in soil moisture for coconuts grown in Typic Kandiudult soil was observed. Furthermore, good correlations were observed between Ψw and the increase in soil moisture in coconuts grown in both soil classes as well as between Fv/Fm and the increase in soil density in coconuts grown in Typic Kandiudult soil. Effects of soil compaction were not observed on other physiological variables. Overall, green dwarf coconut trees grown in Umbric Dystrochrept soil allowed the higher water storage, which may contribute to increases in circumference, plant height, leaf area and dry weight (leaves, stem and root) linked to high photosynthetic rates.
RESUMO A utilização da técnica de enxertia em maracujazeiros tem sido uma estratégia promissora p... more RESUMO A utilização da técnica de enxertia em maracujazeiros tem sido uma estratégia promissora para o desenvolvimento de cultivares tradicionais de maracujazeiros que, por sua vez, apresentam raízes suscetíveis a vários patógenos do solo. Contudo, não se conhece o efeito desta técnica sobre as trocas gasosas, as relações hídricas e a eficiência fotoquímica em plantas desta espécie. O objetivo deste trabalho foi estudar a capacidade fotossintética, as relações hídricas e o crescimento de maracujazeiros propagados por semente (PPS) e propagados por enxertia (PPG), submetidos à limitação da disponibilidade de água no solo. O presente estudo foi realizado em casa de vegetação, utilizando mudas de Passiflora edulis f. flavicarpa e mudas enxertadas [Passiflora edulis f. flavicarpa (enxerto) e Passiflora mucronata (porta-enxerto)] cultivadas em potes de 3,5 dm3. Aos 37 dias após o transplantio (DAT), foi suspensa a irrigação em metade das plantas propagadas por sementes (PPSDS, plantas pr...
ABSTRACT Plantas de Coffea canephora Pierre foram cultivadas em recipientes de diferentes volumes... more ABSTRACT Plantas de Coffea canephora Pierre foram cultivadas em recipientes de diferentes volumes (50, 100, 200, 300 e 3400 mL), contendo Plantmax® como substrato. As plantas cresceram sob telado com 50% de interceptação da densidade de fluxo de fótons fotossintéticos (PPFD), sendo utilizado um sistema de irrigação do tipo nebulização intermitente. No local, foram monitoradas a temperatura, a umidade relativa do ar e a PPFD. O objetivo desse trabalho foi avaliar os efeitos de diferentes volumes de recipientes de cultivo, ao longo do tempo, sobre algumas características biométricas e sobre a taxa de assimilação de CO2. Quando comparadas com as plantas crescidas nos recipientes de 3400 mL, as que que cresceram nos recipientes de 50, 100, 200 e 300 mL apresentaram menores medidas biométricas. As diferenças foram observadas a partir da 5a semana após transplantio (SAT) para o comprimento da nervura central (CNC), da 16aSAT para a altura (H), massa seca da parte aérea (MSPA), massa seca radicular (MSR), área foliar (AF), área radicular (AR), volume radicular (VR) e da 20a SAT para número de folhas (NF). Entre as plantas de Coffea c. crescidas nos diferentes recipientes de cultivo, as diferenças encontradas nos valores das medidas biométricas estudadas parecem não estar relacionadas com a taxa fotossintética líquida, expressa por unidade de área da folha. No entanto, a síntese global de fotoassimilados foi fortemente afetada por meio do impacto no desenvolvimento.
Introduction. Papaya is one of the very few fruit crops multiplied by seed. Unfortunately, the us... more Introduction. Papaya is one of the very few fruit crops multiplied by seed. Unfortunately, the use of seedlings hampers the preservation of favorable plant characteristics and delays the appearance of the first flowers. In addition, the polygamous nature of papaya imposes planting 3-4 seedlings per hole in order to be certain of obtaining the right sex type. These shortcomings can be circumvented by clonal multiplication. This work aimed to multiply selected papaya cultivars from cuttings using the rooting promoting auxin indole-3-butyric acid (IBA). Materials and methods. Two experiments were conducted; the first one followed a completely randomized factorial design, with cultivars 'Golden' and 'Uenf/Caliman 01' as levels of the first factor, and 0, 500, 1,000, 1,500, and 2,000 ppm IBA as levels of the second factor. In this first trial, rooted cuttings of 'Uenf/Caliman 01' were taken to the field and compared to seedlings soon after planting and 4.5 months later. In the second experiment, IBA levels were increased aiming to enhance rooting percentage. Physiological assessments of rooted cuttings were also performed in this second experiment. Results and discussion. A concentration of 3,000 ppm IBA gave the best results for 'Golden', while lower concentration (1,500 ppm) seemed indicated for 'Uenf/Caliman 01'. Rooting success in 'Uenf/Caliman 01' was improved by using cuttings obtained from beheaded mother plants. The analyses showed that a few roots were sufficient to maintain good water status and photosynthetic rate in new plantlets. Conclusion. Plants propagated from cuttings had early flowering and produced first fruits at a lower height than seedlings in the field.
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