Alterações anatômicas em folhas e raízes deResumo -A espécie Jatropha curcas L. está entre as mais destacadas fontes de grãos oleaginosos, com baixa exigência hídrica e nutricional, sendo promissora para regiões áridas e semiáridas, em geral sujeitas à salinização do solo. Objetivou-se neste trabalho avaliar o efeito de diferentes concentrações salinas, sobre a anatomia de folhas e raízes de Jatropha curcas. Cinqüenta sementes foram semeadas em bandejas, e as plântulas transferidas para potes com capacidade para 5 litros, o ensaio foi conduzido em casa de vegetação. Após 21 dias da germinação, as plantas foram submetidas aos seguintes tratamentos salinos: 25; 50; 75; 100; 150 e 200 mM de NaCl, além do controle (0 mM de NaCl), em delineamento inteiramente casualizado, com cinco repetições por tratamento. Ao final do 32º dia de tratamento, a terceira folha e raízes, medindo aproximadamente 5 cm de comprimento, foram coletadas e fixadas em FAA 50. Seções transversais da porção mediana da nervura central da folha e da região mediana da raiz foram cortadas e coradas com safrablau. Foram observadas na folha redução no número de células do xilema e floema e alterações em sua distribuição, em função do aumento das concentrações de sal na solução. Nas raízes observou-se que, quanto mais alta a concentração salina, maior a lignificação das células xilemáticas e endodérmicas, e maior a redução no diâmetro e no número de elementos de vaso. Portanto, ocorrem alterações anatômicas em folhas e raízes das plantas quando cultivadas sob altas concentrações salinas.Palavras-chave -Pinhão-manso. Morfologia. Cloreto de sódio. Abstract -The species Jatropha curcas L. is among the most prominent sources of oilseeds, with low water requirement and nutrition, and promising to arid and semiarid regions, usually subject to soil salinization. The objective of this study was to evaluate the effect of different salt concentrations on the anatomy of leaves and roots of Jatropha curcas. Fifty seeds were sown in trays and the seedlings transferred to pots with a capacity of 5 liters, the test was conducted in a greenhouse. After 21 days of germination, the plants were subjected to the following saline treatments: 25; 50; 75; 100; 150 and 200 mM NaCl, and the control (0 mM NaCl) in a randomized design with five replicates per treatment. At the end of the 32 days of treatment, the third leaf and roots measuring approximately 5 cm in length, were collected and fixed in FAA 50. Transverse sections from the leaves middle portion and the middle region of the root were cut and stained with safrablau. Were observed the reduction in xylem and phloem leaf cells and changes in their distribution as a function of increasing concentrations of salt in the solution. In roots it was observed that the high salt concentration increased xylem cells and endoderm lignification and reduced diameter and number of vessel elements. Thus, the species studied has considerable anatomical changes in leaves and roots when grown under high salt concentrations.

We have investigated the survival of Callosobruchus maculatus larvae when reared on resistant IT81D 1045 Vigna unguiculata seeds, whose resistance has been associated with variant forms of vicilins. Here, we present data which show that larvae of C. maculatus feeding on embryonic axis of resistant cowpea reach a mass of around 28 times higher than those feeding on cotyledonary tissues. Additionally, incorporation of 5-10% of embryonic axis flour on artificial seeds made of resistant flour restores toxicity of seeds to the bruchid. Vicilins purified from both susceptible and resistant embryonic axis had no deleterious effects either on insect development or on insect survival until a level of 4% of incorporation. In contrast, vicilins from resistant cotyledons show an LD 50 (50% lethal dose) and WD 50 (half weight dose) of 2%. Total vicilin contents of embryonic axes were around two times lower than in cotyledonary tissues, while proteolytic activities of all four proteinase classes were always higher in the former tissues. By 2D-PAGE we visualized eight protein spots, which seem to be exclusively found on resistant cotyledons.

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LED induced chlorophyll fluorescence analysis is employed to investigate the effect of water deficit and salt stress upon the growth process of Jatropha curcas L.. Red(Fr) and far-red(FFr) chlorophyll fluorescence around 685 nm and 735 nm, respectively, were observed and examined as a function of the stress intensity(salt concentration and water deficit). The fluorescence ratio Fr/FFr which is a valuable nondestructive and nonintrusive indicator of the chlorophyll content of leaves was exploited to monitor the jatropha plants under stress. The data indicated that salinity plays a minor role in the chlorophyll concentration of leaves for NaCl concentrations in the 25 to 200 mM range. The fluorescence ratio also permitted the detection of damage caused by water deficit in the early stages of the plants growing process. A significant variation of the Fr/FFr ratio was observed in the first 10 days of the experiment, and before signs of visual stress became apparent. The results suggest that the Fr/FFr ratio is an early-warning indicator of water deficit stress.

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