68(P-47) 植物はなぜ眠るのか? : 就眠運動阻害剤を用いたアプローチと環境調和型アグロケミカルへの応用(ポスター発表の部)

Most legumes close their leaves in the evening, and open them at the morning. This movement is called nyctinasty. "Why does the leguminous plant sleep?" is the unsolvable question about the nyctinasty. Darwin and Bunning had a view to this problem, for example Darwin said that it is a movement to guard against the coldness of the night, and Bunning said it is to prevent reset of the biological clock by moonlight. But it couldn't be a theory cause they didn't have much supporting data. On base of the mechanism of nyctinastic movement, we have synthesized an inhibitor (2) of nyctinastic movement from the leaf-opening substance of Cassia mimosoides L., thinking that legumes don't sleep will be a solution for the question. 2 had successfully inhibited nyctinastic movement and made the plant insomnia. Also we have found that insomnia plant withers in a week or two. And gave a key to solve the question "Why does the leguminous plant sleep?" that nyctinastic movement is essential for leguminous plants to survive. Two factors, that nyctinastic movement is essential for leguminous plants to survive, and leaf-opening substance is specific to each genus, suggested the use of nyctinastic movement inhibitor as the highly specific agrochemical. We have targeted Sesbania exaltata Cory, the weed becoming a problem on soybean plantation in USA. From the extraction of the Sesbania speciosa Taub., predicted to have the same leaf-opening substance with the S. exaltata Cory, we have isolated potassium 4-O-β-D-glucopyranosyl-trans-p-coumarate (11) as the leaf-opening factor. 11 was confirmed to be specific to the Sesbania genus, so next we synthesized an inhibitor (12 and 13) from 11. The synthesized 12 and 13 was first confirmed to be specific to Sesbania genus, and then used to S. exaltata Cory. 12 and 13 had successfully withered the plant and showed the possibility for the use of nyctinastic movement inhibitor as the highly specific agrochemical.