Leaf morpho-anatomy of Jatropha curcas in vitro: Response to light conditions and temperature

Abstract

Jatropha curcas L. plant is adapted to diverse climatic conditions with high requirement of heat stroke and drought resistant, having a special position among the attractive crops to biofuel program. This species has been studied from the perspectives of plant breeding, biotechnology and development of production systems. However, there are few reports of research regarding its anatomical characteristics. Thus, the objective of this study was to evaluate the effects of different conditions of light and temperature on the germination in vitro of J. curcas embryo and describe the leaf structure of seedlings through anatomical and micromorphological parameters. Embryos were excised and cultured in test tubes containing 15 ml of MS medium and grown in different temperature (25 °C and 30 °C) and light conditions (white, red, far red, and absence of light). The cultures were kept in BOD germinators chambers, with a 16 h photoperiod. Phytotechnical, anatomical and micromorphological (via electron scanning microscopy) characteristics were measured. The species J. curcas has a higher germination speed index when grown at 30 ºC. There is an increased of number of normal seedlings in white light and this point characterizes the species as neutral photoblastic. J. curcas presents uniseriate epidermis, palisade unistratified parenchyma, and spongy parenchyma composed of irregular cells. It is an amphistomatic species, with more stomata on the abaxial surface.