O pinhão-manso (Jatropha curcas L.) tem-se destacado, no cenário do biodiesel, em função da porcentagem de óleo contido nas sementes e de sua capacidade adaptativa. No País, a cultura do pinhão-manso tem, como proposta, o desenvolvimento agronômico, razão pela qual o uso consorciado pode ser importante aos pequenos produtores. Este trabalho teve como objetivo avaliar algumas características fenológicas de pinhão-manso cultivado em dois regimes de luminosidade (pleno sol e sombrite 50%) relacionando com a sazonalidade climática e se utilizando de parâmetros da fluorescência da clorofila e de trocas gasosas. As plantas apresentaram crescimento vegetativo com padrão sazonal, com pico de crescimento no início de março, quando iniciou a senescência foliar. Alguns parâmetros da fluorescência transiente da clorofila analisados pelo Teste JIP, apresentaram relação com as flutuações ambientais. O PI ABS e o PItotal demonstraram que as plantas do tratamento sombreado foram sensíveis à redução de luminosidade. A taxa assimilatória líquida e a eficiência de carboxilação reduziram ao longo do experimento acompanhando a queda da radiação solar; já as plantas de pinhão-manso respondem negativamente a essas condições de sombreamento.

Jatropha curcas L. has been prominent in the scenario of biodiesel due to the percentage of oil contained in the seeds and its adaptive capacity. The cultivation of J. curcas in the country has as proposal the agronomic development and its consortium may be important for small producers. This study aimed to characterize the phenological behavior of J. curcas grown under different light conditions, full sun and 50% shade, relating them to the climatic seasonality, comparing their development with chlorophyll a fluorescence and gas exchange. Plants showed vegetative growth with seasonal pattern, with growth peak at the beginning of March, when the leaf senescence began. The analysis of the kinetic of the transient fluorescence of chlorophyll presented a relationship between certain parameters of the test JIP and the environmental fluctuations. The PI ABS and the PItotal demonstrated that in the shaded treatment plants were sensitive to luminosity reduction. The liquid assimilation rate and the carboxylation efficiency decreased throughout the experiment, accompanying the decline of the solar radiation. J. curcas plants respond negatively to these shaded conditions.

This study aimed to evaluate the effect of flooding and water restriction (drought) on the photosynthetic activity in plants of the hybrid rootstock 'GxN-9' (Prunus dulcis Mill. × Prunus persica L. Bastsch), grown in a greenhouse. Chlorophyll fluorescence and gas exchange were analyzed in plants of approximately 12 months. The reduction of photosynthetic activity in both the stresses were associated with decreased carboxylation efficiency, but without affecting the internal concentration of carbon dioxide. The JIP-test parameters revealed changes in the energy flux processes demonstrating that in terms of flooding the rootstock GxN-9 the rate of photosynthetic performance significantly decreases, resulting in a considerable decrease in net assimilation rate. The JIP-test analysis was efficient in determining the thresholds mainly of the flood response, proving to be useful in exploration of the photosynthetic activity as a physiological marker of the stress tolerance.