Leaf trait variation on Erythroxylum tortuosum (Erythroxylaceae) and its relationship with oviposition preference and stress by a host-specific leaf miner

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Seed quality, chlorophyll content index and leaf nitrogen levels in maize inoculated with Azospirillum brasilense

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Effect of nitrogen supply on growth and photosynthesis of sunflower plants grown in the greenhouse

The effects of nitrogen availability on growth and photosynthesis were followed in plants of sunflower (Helianthus annuus L., var. CATISSOL-01) grown in the greenhouse under natural photoperiod. The sunflower plants were grown in vermiculite under two contrasting nitrogen supply, with nitrogen supplied as ammonium nitrate. Higher nitrogen concentration resulted in higher shoot dry matter production per plant and the effect was apparent from 29 days after sowing (DAS). The difference in dry matter production was mainly attributed to the effect of nitrogen on leaf production and on individual leaf dry matter. The specific leaf weight (SLW) was not affected by the nitrogen supply. The photosynthetic CO2 assimilation (A) of the target leaves was remarkably improved by high nitrogen nutrition. However, irrespective of nitrogen supply, the decline in photosynthetic CO2 assimilation occurred before the end of leaf growth. Although nitrogen did not change significantly stomatal conductance (gs), high-N grown plants had lower intercellular CO2 concentration (C-i) when compared with low-N grown plants. Transpiration rate (E) was increased in high-N grown plants only at the beginning of leaf growth. However, this not resulted in lower intrinsic water use efficiency (WUE). (C) 2004 Elsevier B.V.. All rights reserved.

Avaliações fisiológicas e bioquímicas de plantas de aguapé (Eichhornia crassipes) cultivadas com níveis excessivos de nutrientes

Plantas de aguapé foram cultivadas em solução nutritiva de Hoagland & Arnon n.2, cujo aumento dos níveis de N, P e Cu estabeleceu as diferenças entre os tratamentos. Utilizou-se o delineamento experimental inteiramente casualizado, com quatro repetições. As variáveis fisiológicas avaliadas foram área foliar, peso de matéria seca e taxa de crescimento absoluto, taxa de crescimento relativo, taxa assimilatória líquida, razão de área foliar, peso específico de folha, área foliar específica. Foram determinados também os teores de açúcares totais e redutores e de aminoácidos totais e a atividade das enzimas glutationa S-transferase e superóxido dismutase. Os extratos enzimáticos foram obtidos da matéria fresca da parte aérea das plantas. Após a coleta, foram determinados os pesos de material seco de raízes, pecíolos e folhas, que foram utilizados para a determinação de açúcares solúveis totais e redutores e de aminoácidos. O excesso de nitrogênio causou aumento de açúcares nas folhas e de aminoácidos nas raízes. Já o tratamento com excesso de fósforo levou ao aumento de açúcares nas raízes. Os resultados apresentados sugerem que, entre os nutrientes em excesso avaliados, o cobre (0,12 mg L-1) foi o maior indutor da atividade da GST e SOD, sugerindo que este elemento induziu estresse nas plantas de aguapé.

Structural and functional leaf traits of two Gochnatia species from distinct growth forms in a sclerophyll forest site in Southeastern Brazil

O gênero Gochnatia é comumente encontrado em diferentes fitofisionomias do Cerrado do Estado de São Paulo, crescendo desde ambientes mais abertos até áreas florestais mais fechadas. Aqui foram comparadas a anatomia foliar e alguns parâmetros ecofisiológicos de duas espécies do gênero Gochnatia, uma arbustiva (Gochnatia barrosii Cabrera) e a outra arbórea (Gochnatia polymorpha (Less.) Cabrera), ambas ocorrendo em área de cerradão na Estação Ecológica de Assis, SP. Encontraram-se diferenças estruturais qualitativas entre as espécies, com G. barrosii apresentando folhas anfiestomáticas, com epiderme unisseriada e G. polymorpha apresentando folhas hipoestomáticas, com epiderme múltipla ou hipoderme, na face adaxial. Além disso, as folhas de G. barrosii apresentaram menores valores para a espessura dos tecidos (com exceção da epiderme na face abaxial) e da folha em relação a G. polymorpha. Foram observadas diferenças na assimilação de CO2 tanto em base de área quanto de massa seca foliar, além de diferenças na área foliar específica, sendo esta maior em G. barrosii. Apesar das folhas de G. barrosii possuírem estrutura bem menos escleromorfa do que as folhas de G. polymorpha, não foram encontradas diferenças na eficiência do uso de água. Os resultados sugerem que espécies de formas distintas de crescimento de um mesmo gênero possuem características foliares diferenciadas para lidar com as variações ambientais a que são submetidas.

Root, shoot and leaf traits of the congeneric Styrax species may explain their distribution patterns in the cerrado sensu lato areas in Brazil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Photosynthetic and anatomical responses of Eucalyptus grandis leaves to potassium and sodium supply in a field experiment

Although vast areas in tropical regions have weathered soils with low potassium (K) levels, little is known about the effects of K supply on the photosynthetic physiology of trees. This study assessed the effects of K and sodium (Na) supply on the diffusional and biochemical limitations to photosynthesis in Eucalyptus grandis leaves. A field experiment comparing treatments receiving K (+K) or Na (+Na) with a control treatment (C) was set up in a K-deficient soil. The net CO2 assimilation rates were twice as high in +K and 1.6 times higher in +Na than in the C as a result of lower stomatal and mesophyll resistance to CO2 diffusion and higher photosynthetic capacity. The starch content was higher and soluble sugar was lower in +K than in C and +Na, suggesting that K starvation disturbed carbon storage and transport. The specific leaf area, leaf thickness, parenchyma thickness, stomatal size and intercellular air spaces increased in +K and +Na compared to C. Nitrogen and chlorophyll concentrations were also higher in +K and +Na than in C. These results suggest a strong relationship between the K and Na supply to E. grandis trees and the functional and structural limitations to CO2 assimilation rates. © 2013 John Wiley & Sons Ltd.

Seasonal variation in leaf traits between congeneric savanna and forest trees in Central Brazil: Implications for forest expansion into savanna

The ecology of forest and savanna trees species will largely determine the structure and dynamics of the forest-savanna boundaries, but little is known about the constraints to leaf trait variation imposed by selective forces and evolutionary history during the process of savanna invasion by forest species. We compared seasonal patterns in leaf traits related to leaf structure, carbon assimilation, water, and nutrient relations in 10 congeneric species pairs, each containing one savanna species and one forest species. All individuals were growing in dystrophic oxisols in a fire-protected savanna of Central Brazil. We tested the hypothesis that forest species would be more constrained by seasonal drought and nutrient-poor soils than their savanna congeners. We also hypothesized that habitat, rather than phylogeny, would explain more of the interspecific variance in leaf traits of the studied species. We found that throughout the year forest trees had higher specific leaf area (SLA) but lower integrated water use efficiency than savanna trees. Forest and savanna species maintained similar values of predawn and midday leaf water potential along the year. Lower values were measured in the dry season. However, this was achieved by a stronger regulation of stomatal conductance and of CO2 assimilation on an area basis (A area) in forest trees, particularly toward the end of the dry season. Relative to savanna trees, forest trees maintained similar (P, K, Ca, and Mg) or slightly higher (N) leaf nutrient concentrations. For the majority of traits, more variance was explained by phylogeny, than by habitat of origin, with the exception of SLA, leaf N concentration, and A area, which were apparently subjected to different selective pressures in the savanna and forest environments. In conclusion, water shortage during extended droughts would be more limiting for forest trees than nutrient-poor soils. © 2013 Springer-Verlag Berlin Heidelberg.

Leaf anatomical traits are correlated with tree dominance in a Neotropical deciduous forest

Deciduous forests from the neotropics are one of the most endangered forest types in the world due to the exploitation of their natural resources by mankind. Many aspects of these ecosystems have been studied; however, there is a lack of information about leaf structure and the effects of tree dominance on their structural leaf patterns. In this article, we examine leaf anatomy and specific leaf areas (SLA) in 13 tree species differing in their dominance in a Dry Forest site in Central Brazil, relating leaf anatomical traits with phytosociological aspects. Leaf anatomical traits differed according to tree dominance: greater leaf thickness (achieved through greater thickness of the mesophyll), low values of SLA and bigger stomata were found for the most dominant species, whereas the less dominant species showed thinner leaves with high SLA, as well as numerous and small stomata. These responses suggest that tree dominance is an important indirect effect associated with vertical light availability in the forest. These strategies are probably related to the accomplishment of a high performance in carbon gain and water economy, given the distinction in irradiance that the leaves of different species are subject to in the dry forest. © 2013 Copyright The Royal Society of New Zealand.

Desenvolvimento, produção e composição de óleo essencial da Mentha piperita L., cultivada em solução nutritiva com diferentes níveis de nitrogênio

Pós-graduação em Agronomia (Horticultura) - FCA

Potencial antioxidante, óleo essencial e atividade antifúngica de plantas de jambu (Spilanthes oleracea), cultivadas sob adubação orgânica e convencional e processamento mínimo de nectarina (Prunus persica var. nectarina): conservação de suas qualidades e propriedades bioativas

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Desenvolvimento, trocas gasosas, rendimento e composição de óleo essencial de Mentha piperita L. cultivada em solução nutritiva com variação dos níveis de N, P, K e Mg

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Leaf Morphological Plasticity of Tree Species from Two Developmental Stages in Araucaria Forest

This study compared the morphological and anatomical variations of the leaves of four shade-tolerant tree species Allophylus edulis (St.-Hil.) Radlk (Sapindaceae), Casearia sylvestris Sw. (Salicaceae), Cupania vernalis Cambess. (Sapindaceae) and Luehea divaricata Mart. (Malvaceae) from a fragment of Araucaria forest in two developmental stages. Morphological and anatomical traits, such as leaf and tissue thickness, leaf area, leaf dry mass, specific leaf area, leaf density and stomata density were measured from 30 leaves of each developmental stage. The phenotypic plasticity index was also calculated for each quantitative trait. The results showed that the four species presented higher mean values ​​for specific leaf area and spongy/palisade parenchyma ratio at young stage, and higher mean values ​​for stomata density, total and palisade parenchyma thickness in the adult stage. The plasticity index demonstrated that L. divricata presented highest plasticity for both the morphological and anatomical traits while A. edulis displayed the lowest plasticity index. The results of this study indicated that the leaves of these species exhibited distinct morphological traits at each stage of development to cope with acting environmental factors.

Leaf anatomical traits corroborate the leaf economic spectrum: a case study with deciduous forest tree species

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Do litter manipulations affect leaf functional traits of savanna woody plants?

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)