Papers by Luis Mauro Gonçalves Rosa
Trees, 2010
Araucaria angustifolia exhibits cryptogeal germination, where the root-hypocotyl axis emerges fir... more Araucaria angustifolia exhibits cryptogeal germination, where the root-hypocotyl axis emerges first and penetrates into the soil. In Araucaria bidwillii, the whole process of transferring reserves from the seed to the seedling takes place before shoot emergence, and there is a major storage of these reserves in the underground hypocotyl, which assumes a tuberous form. In A. angustifolia, the shoot emerges before seed reserves are depleted. Though it does not grow like a tuber, the hypocotyl of A. angustifolia grows thicker than the adjacent taproot during initial growth, and we hypothesize that it may act as a major sink for seed reserves during this stage. The study tests this hypothesis by evaluating changes in the mass of different plant parts during initial growth. Four harvests were conducted during a *6-month period to compare the dry mass of different fractions (attached seed, seedling, its shoot and root and the hypocotyl) of seedlings growing under darkness and high light. While seed reserves were still being depleted, the hypocotyl mass showed an initial increase and then a reduction. This was more abrupt when light was available. After seed mass had stabilized, the mass of the hypocotyl continued to decrease in the darkgrown seedlings, but showed a second increase in the lightgrown ones. Results confirm the hypothesis that the hypocotyl represents a major sink for the seed reserves of A. angustifolia, acting as an underground storage structure for the growing seedling. Its reserves seem to be important for sustaining initial shoot growth and might also act as a storage sink for photosynthates.
Australian Journal of Botany, 2002
The role of Brazilian pine (Araucaria angustifolia) in the process of forest succession is a topi... more The role of Brazilian pine (Araucaria angustifolia) in the process of forest succession is a topic of increasing controversy. While some authors consider the species to be pioneer. others consider it to be a climax species in relict temperate forests. We designed a field experiment to assess the role of light availability on the regeneration oLL angustilolia. The following three forests. with contrasting patterns of the species regeneration. were selected at a National Forest in southern Brazil: a Pinus plantation. an Araucaria plantation and a native araucarian forest. We ana lysed the population structure of Brazilian pine, the vegetation architecture. the light regime experienced by seedlings and the height growth of seedlings and sprouts. Brazilian pine colonisation and regeneration were observed in the Pinus and Araucaria plantations. respectively. No seedlings were found in the native forest. The greatest foliage area index and canopy cover were found in the native forest and the smallest in the Pinus plantation. In spite of the architectural differences. the native forest and the Araucaria plantation had similar light conditions and they both had lower levels of irradiances than the Pinus plantation. Seedlings and sprouts of Brazilian pine were found to occupy spots in the Araucaria plantation with canopy cover greater than the average forest conditions. Considering the similarity of understorey light conditions between the Arallcaria plantation and the native forest (where no regeneration was taking place). we concluded that light availability was not limiting the regeneration of the species. Tolerance to shading and other aspects of the species indicate that Brazilian pine is not strictly heliophyllous and pioneer and is able to be established in the forest understarey.
Crop water monitoring is an important aspect for precise control of irrigation. A reliable and mo... more Crop water monitoring is an important aspect for precise control of irrigation. A reliable and movable technique is needed to properly assess water uptake of crops in the field. Water uptake by field grown maize (Zea mays L.), in water-limited conditions was verified with the heat pulse system. The temperature difference between two radially inserted thermocouples, one 9 mm above
Acta Physiologiae Plantarum, 2010
The phenolic compound content of Hypericum ternum was investigated after micropropagation establi... more The phenolic compound content of Hypericum ternum was investigated after micropropagation establishment and during acclimatization over the phenological development of the plant. Plantlets cultured in vitro on full Murashige and Skoog medium without growth regulators displayed higher phenolic compound yields, were acclimatized, and field grown. Production of total phenolic compounds as well as hyperoside, chlorogenic acid, quercitrin, guaijaverin, isoquercitrin, and uliginosin B were quantified at vegetative, flowering and fructification stages, and different plant organs (roots, stems, leaves and reproductive parts) showing that reproductive parts at flowering stage and the leaves at fructification stage were the main repository site of secondary metabolites, except for uliginosin B. The stems were the least accumulative organ, while the roots accumulated only hyperoside and uliginosin B. Moreover, the accumulation of most of the flavonoids and uliginosin B in acclimatized plants surpassed the levels found in the wild plant, warranting further research with the species.
Diversos estudos realizados têm demostrado a importância do nitrogênio como elemento essencial pa... more Diversos estudos realizados têm demostrado a importância do nitrogênio como elemento essencial para o crescimento e desenvolvimento vegetal. Constituinte indispensável de aminoácidos, proteínas, nucleotídeos, ácidos nucleicos, clorofilas e coenzimas, o nitrogênio é, dos macronutrientes minerais, o mais limitante, afetando diretamente a fotossíntese, a taxa de crescimento e o acúmulo de matéria seca das plantas. Este trabalho foi realizado com Paspalum urvillei (Steud), espécie forrageira nativa dos campos do Rio Grande do Sul, e teve por objetivo conhecer o comportamento fisiológico desta espécie em termos de fotossíntese e crescimento, ao ser submetida a diferentes níveis de disponibilidade de nitrogênio. Os resultados obtidos nos permitem concluir preliminarmente que as plantas da espécie estudada responderam ao incremento de nitrogênio com maior investimento em número de folhas e maior afilhamento em detrimento do comprimento das folhas componentes da planta, numa maior taxa de crescimento relativo e retardamenento do início da fase de senescência e também numa maior taxa fotossíntética por unidade de área foliar. (FAPERGS).
Revista Brasileira de Engenharia Agrícola e Ambiental, 1999
Crop water monitoring is an important aspect for precise control of irrigation. A reliable and mo... more Crop water monitoring is an important aspect for precise control of irrigation. A reliable and movable technique is needed to properly assess water uptake of crops in the field. Water uptake by field grown maize (Zea mays L.), in water-limited conditions was verified with the heat pulse system. The temperature difference between two radially inserted thermocouples, one 9 mm above and the other 4 mm below a heater piercing the maize stem, was measured every 0.3 sec following emission of a heat pulse in conditions of varied atmospheric demand. Comparisons of heat pulse system outputs and a high precision transpiration model estimates were done on hourly and daily basis, when low sap velocities were expected to occur. Hourly and daily basis of the heat pulse outputs and model estimates were in agreement. Sensitiveness of the technique was observed even for very low sap velocities.
Agriscientia, 2000
The precise determination of water loss from plant canopies is important for monitoring crop wate... more The precise determination of water loss from plant canopies is important for monitoring crop water usage and for many agricultural management operations related to water use planning. The aim of this study was to estimate water loss from sunlit and shaded fractions of a maize (Zea mays L.) canopy, under wellwatered conditions, using the Penman-Monteith energy balance equation. Estimated values were validated by a heat pulse system, which was used to measure stem sap flow and by a weighing lysimeter. Water loss was corrected to account for the effect of row structure in the early stages of maize. Results showed that estimated transpiration of the shaded canopy ranged from 30% to 45% for total transpiration, under fluctuation of atmospheric demand. Hourly and daily estimations of transpiration showed good agreement with lysimeter and heat pulse measurements.
Postal 776, CEP 91501-970, Porto Alegre -RS. 2 Autor para correspondência RESUMO A quantidade tot... more Postal 776, CEP 91501-970, Porto Alegre -RS. 2 Autor para correspondência RESUMO A quantidade total de radiação fotossinteticamente ativa (PAR) absorvida é o principal determinante da taxa de crescimento e da produtividade das culturas. Entretanto, em estações meteorológicas padrão, somente a radiação solar global (Rs) é disponível.
Trees, 2010
Araucaria angustifolia exhibits cryptogeal germination, where the root-hypocotyl axis emerges fir... more Araucaria angustifolia exhibits cryptogeal germination, where the root-hypocotyl axis emerges first and penetrates into the soil. In Araucaria bidwillii, the whole process of transferring reserves from the seed to the seedling takes place before shoot emergence, and there is a major storage of these reserves in the underground hypocotyl, which assumes a tuberous form. In A. angustifolia, the shoot emerges before seed reserves are depleted. Though it does not grow like a tuber, the hypocotyl of A. angustifolia grows thicker than the adjacent taproot during initial growth, and we hypothesize that it may act as a major sink for seed reserves during this stage. The study tests this hypothesis by evaluating changes in the mass of different plant parts during initial growth. Four harvests were conducted during a *6-month period to compare the dry mass of different fractions (attached seed, seedling, its shoot and root and the hypocotyl) of seedlings growing under darkness and high light. While seed reserves were still being depleted, the hypocotyl mass showed an initial increase and then a reduction. This was more abrupt when light was available. After seed mass had stabilized, the mass of the hypocotyl continued to decrease in the darkgrown seedlings, but showed a second increase in the lightgrown ones. Results confirm the hypothesis that the hypocotyl represents a major sink for the seed reserves of A. angustifolia, acting as an underground storage structure for the growing seedling. Its reserves seem to be important for sustaining initial shoot growth and might also act as a storage sink for photosynthates.
Plant Physiology and Biochemistry, 2008
Accumulation of benzopyrans and total phenolic compounds were assessed in acclimatized field grow... more Accumulation of benzopyrans and total phenolic compounds were assessed in acclimatized field grown plants of Hypericum polyanthemum, an endemic species of southern Brazil, harvested at different developmental stages. The HPLC analysis of bioactive compounds 6-isobutyryl-5,7-dimethoxy-2,2-dimethylbenzopyran (HP1), 7-hydroxy-6-isobutyryl-5-methoxy-2,2-dimethyl-benzopyran (HP2) and 5-hydroxy-6-isobutyryl-7-methoxy-2,2-dimethyl-benzopyran (HP3) revealed that the three benzopyrans are accumulated both in the vegetative and reproductive parts with maximum contents observed after 18 weeks (in the former) and 20 weeks (in the later) of plant growth (1.92 AE 0.085 g % DW and 2.62 AE 0.13 g % DW in the vegetative and reproductive parts, respectively). Highest contents of HP1 (1.56 AE 0.12 g % DW) and HP2 (0.19 AE 0.01 g % DW) were quantified in the green floral buds of the plants, whereas HP3 reached the highest level (1.02 AE 0.08 g % DW) in the overblown flowers. The evaluation of total phenolic compounds showed that the vegetative parts accumulated the highest levels of the metabolites (51.93 AE 0.67 mg QE (g DW) À1 ) after 16 weeks of plant growth. Considering the reproductive parts, the open flowers accumulated the greatest levels of the bioactive compounds (75.99 AE 0.95 mg QE (g DW) À1 ). The results show that H. polyanthemum can be efficiently propagated and acclimatized to produce benzopyrans and other phenolic compounds.
Australian Journal of Botany, 2002
The role of Brazilian pine (Araucaria angustifolia) in the process of forest succession is a topi... more The role of Brazilian pine (Araucaria angustifolia) in the process of forest succession is a topic of increasing controversy. While some authors consider the species to be pioneer. others consider it to be a climax species in relict temperate forests. We designed a field experiment to assess the role of light availability on the regeneration oLL angustilolia. The following three forests. with contrasting patterns of the species regeneration. were selected at a National Forest in southern Brazil: a Pinus plantation. an Araucaria plantation and a native araucarian forest. We ana lysed the population structure of Brazilian pine, the vegetation architecture. the light regime experienced by seedlings and the height growth of seedlings and sprouts. Brazilian pine colonisation and regeneration were observed in the Pinus and Araucaria plantations. respectively. No seedlings were found in the native forest. The greatest foliage area index and canopy cover were found in the native forest and the smallest in the Pinus plantation. In spite of the architectural differences. the native forest and the Araucaria plantation had similar light conditions and they both had lower levels of irradiances than the Pinus plantation. Seedlings and sprouts of Brazilian pine were found to occupy spots in the Araucaria plantation with canopy cover greater than the average forest conditions. Considering the similarity of understorey light conditions between the Arallcaria plantation and the native forest (where no regeneration was taking place). we concluded that light availability was not limiting the regeneration of the species. Tolerance to shading and other aspects of the species indicate that Brazilian pine is not strictly heliophyllous and pioneer and is able to be established in the forest understarey.
Agricultural and Forest Meteorology, 2009
Acta Physiologiae Plantarum, 2010
The phenolic compound content of Hypericum ternum was investigated after micropropagation establi... more The phenolic compound content of Hypericum ternum was investigated after micropropagation establishment and during acclimatization over the phenological development of the plant. Plantlets cultured in vitro on full Murashige and Skoog medium without growth regulators displayed higher phenolic compound yields, were acclimatized, and field grown. Production of total phenolic compounds as well as hyperoside, chlorogenic acid, quercitrin, guaijaverin, isoquercitrin, and uliginosin B were quantified at vegetative, flowering and fructification stages, and different plant organs (roots, stems, leaves and reproductive parts) showing that reproductive parts at flowering stage and the leaves at fructification stage were the main repository site of secondary metabolites, except for uliginosin B. The stems were the least accumulative organ, while the roots accumulated only hyperoside and uliginosin B. Moreover, the accumulation of most of the flavonoids and uliginosin B in acclimatized plants surpassed the levels found in the wild plant, warranting further research with the species.
Acta Botanica Brasilica, 2010
RESUMO -(Crescimento e limitações à assimilação de carbono em Ricinus communis (Euphorbiaceae) so... more RESUMO -(Crescimento e limitações à assimilação de carbono em Ricinus communis (Euphorbiaceae) sob condições de estresse hídrico do solo). A disponibilidade hídrica pode infl uenciar o ganho de carbono e o crescimento, com grande impacto na produtividade das plantas. Ricinus communis (L.), uma espécie resistente à seca, é uma cultura de grande importância econômica no Brasil, devido ao seu uso na indústria química e para a produção de biocombustíveis. Alguns dos mecanismos envolvidos na resistência à seca desta espécie foram analisados através de um progressivo estresse hídrico em plantas cultivadas em vasos sob condições de casa de vegetação. A suspensão da irrigação por 53 dias decresceu o conteúdo gravimétrico de água no solo e o potencial hídrico das folhas. O crescimento das plantas foi negativamente e signifi cativamente reduzido pelo aumento do défi cit hídrico do solo. Com a suspensão da irrigação, a assimilação de carbono e a transpiração foram reduzidas e permaneceram praticamente constantes ao longo do dia. A análise das curvas A/C i demonstrou o aumento da limitação estomática, indicando que a limitação imposta pelo fechamento dos estômatos é o principal responsável pela redução da fotossíntese. A efi ciência de carboxilação e a taxa de transporte de elétrons não foram afetadas pelo estresse hídrico até 15 dias de suspensão da irrigação. A resistência à seca da mamona parece estar relacionada a uma resposta inicial e pronunciada do crescimento, a um efi ciente controle estomático e a capacidade de manter uma alta taxa de fi xação de CO 2 sob condições de estresse hídrico. Palavras-chave: curvas A/Ci, estresse hídrico, fotossíntese, limitação estomática, padrão diário ABSTRACT -(Growth and limitations to carbon assimilation in Ricinus communis (Euphorbiaceae) under soil water stress conditions). Water availability may infl uence plant carbon gain and growth, with large impacts on plant yield. Ricinus communis (L.), a drought resistant species, is a crop with increasing economic importance in Brazil, due to its use in chemical industry and for the production of biofuels. Some of the mechanisms involved in this drought resistance were analyzed in this study by imposing progressive water stress to pot-grown plants under glasshouse conditions. Water withholding for 53 days decreased soil water gravimetric content and the leaf water potential. Plant growth was negatively and signifi cantly reduced by increasing soil water defi cits. With irrigation suspension, carbon assimilation and transpiration were reduced and remained mostly constant throughout the day. Analysis of A/ C i curves showed increased stomatal limitation, indicating that limitation imposed by stomatal closure is the main factor responsible for photosynthesis reduction. Carboxylation effi ciency and electron transport rate were not affected by water stress up to 15 days after withholding water. Drought resistance of castor bean seems to be related to a pronounced, early growth response, an effi cient stomatal control and the capacity to keep high net CO 2 fi xation rates under water stress conditions.
Plant Cell, Tissue and Organ Culture (PCTOC), 2013
ABSTRACT Changes in biomass and bioactive metabolites after treatment with the fungus Nomuraea ri... more ABSTRACT Changes in biomass and bioactive metabolites after treatment with the fungus Nomuraea rileyi (Farlow) Samson added as dried culture (DC) or as dried autoclaved cell powder (DACP) for short and long periods of time have been investigated in Hypericum polyanthemum plants grown under controlled conditions and after 18 weeks of field acclimatization. Plants grown under controlled conditions and treated with DACP showed increased concentrations of the benzopyrans HP1 (6-isobutyryl-5,7-dimethoxy-2,2-dimethylbenzopyran), HP2 (7-hydroxy-6-isobutyryl-5-methoxy-2,2-dimethylbenzopyran), and HP3 (5-hydroxy-6-isobutyryl-7-methoxy-2,2-dimethylbenzopyran) while DC affected negatively or did not alter the synthesis of these compounds. Lower levels of the phloroglucinol derivative uliginosin B were detected in all treatments. Long time treatment with DACP of acclimatized plants triggered doubling of biomass as compared to control and chemical analyses demonstrated significant increase on total phenolic compounds in vegetative parts of plants. Moreover, the higher performance liquid chromatography analysis showed different pattern of metabolites accumulation, with higher yields of HP1, HP2, HP3 and uliginosin B in the reproductive parts of the plants treated with DACP during all experiments. The elevation of bioactive metabolites levels in response to the elicitor suggests that these compounds are inducible as part of the defense response of H. polyanthemum.
RESUMO: SANTOS, A.M.; ROSA, L.M.G.; NABINGER, C.; FRANKE, L.B.; ABREU, J.B.R. Influência da orien... more RESUMO: SANTOS, A.M.; ROSA, L.M.G.; NABINGER, C.; FRANKE, L.B.; ABREU, J.B.R. Influência da orientação foliar e da disponibilidade hídrica na intercepção da radiação solar e no teor de clorofila da folha em Macroptilum lathyroides (L.) Urban. Revista Universidade Rural: Série Ciências da Vida, Seropédica, RJ: EDUR. v. 26 n. 2, p. 01-12, jul-dez, 2006.
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Papers by Luis Mauro Gonçalves Rosa