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Sudan Journal of Agricultural Research

Effect of light on the growth of Orobanche minor Sm

Atsushi Okazawa, Chitra Trakulnaleamsai, Yu Wada, Ei’ichiro Fukusaki, Koichi Yoneyama , Yasutomo Takeuchi and Akio Kobayashi

Abstract:

Holoparasitic Orobanche minor Sm depends on its host for water and nutrients and does not photosynthesize. Lights are utilized not only as energy for photosynthesis but also as environmental signals for plants. The light signals regulate morphology and physiology of plants mainly to maintain the efficient photosynthesis. But some physiological events that are not related to photosynthesis are also controlled by lights. It is not known if those light signaling pathway exists or not in the non-photosynthetic holoparasites. In this study, the light effect on the growth of O. minor was investigated. It was revealed that the germination is inhibited by red (R) light and this inhibition is canceled by following far-red light (FR), indicating the existence of phytochrome signaling systems. It was also revealed that anthocyanin biosynthesis is induced by FR, while the stem elongation is suppressed by FR. It is noteworthy that these R/FR responses are opposite to those of general green plants. This can hypothetically explained that the light sensing systems in the holoparasite evolved not to prevent the photosynthesis of its host.
 

Sudan Journal of Agricultural Research Vol. 10  (2007) PP.115-119