Plants growing in temperate regions are often exposed to stress conditions caused by high temperatures. Photosynthesis is one of the metabolic processes most sensitive to high temperature stress, and it is often inhibited before other cellular functions. Using peach leaf disks, we studied the transient chlorophyll a fluorescence along with the gas exchanges at temperatures of 25 (control)

R E S U M OO 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 PI total 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. Growth and photosynthesis of Physic nut grown under different light conditions A B S T R A C TJatropha 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 PI total 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. Crescimento e fotossíntese de plantas de pinhão-manso cultivadas em diferentes condições de luminosidade

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The objectives were: a) to evaluate the initial development of olive ministumps in semi-hydroponic and conventional systems; b) evaluate the productivity ministumps in successive collections and the rooting of minicuttings of olive tree collected at different times of the year clonal mini garden cultivated in semi-hydroponic and conventional systems. The cultivation systems used were the semi-hydroponics and conventional, to which was evaluated for 90 days of cultivation the initial growth of ministumps. After that began the collection of plant material in cropping systems. The variables analyzed were: the initial growth of ministumps, productivity, the percentage of survival and rooting, the number and length of roots and also found the survival of rooted minicuttings of cropping systems. The cultivation of olive ministumps in semi-hydroponic system is more efficient in minicuttings productivity than the conventional system. The minicuttings collected in separate semi-hydroponic system collecting time showed the best results for the variables analyzed in relation to the conventional system of cultivation.