Mefluidide促进玉米根延伸生长机理的初步探讨

THE MECHANISM OF MEFLUIDIDE-PROMOTED ROOT EXTENSION OF ZEA MAYS

不同品种玉米（ZeamaysL．）种子，分别用5mg／L和10mg／LMefluidide溶液浸泡10h后，在适宜温度（24℃－26℃）和低温（10℃—15℃）暗环境中，其胚根和不定根延伸生长加快。与此同时，可测得Mefluidide处理的种苗较对照有高水平的乙烯产生。用2nl／ml、4nl／ml和6nl／ml外源乙烯处理萌发后的玉米种子，亦可观测到胚根延伸生长较对照有明显加速的趋势。这些结果既直接验证了低浓度乙烯确具有促进植物根系延伸生长的生理效应，也揭示出Mefluidide是经由某一尚未明了的机理诱导玉米幼苗产生微量乙烯，从而促进了根系的延伸生长。文中结合有关报道，对Menuidide的作用机理作了探讨。

Zea mays (A632×103YU and CM105×A671) seeds,treated with 5 mg/L and 10mg/L Mefluidide (N- [2,4-dimethyl-5-[[ (trifluoromethyl) sulfonyl]amino]phenol]acetadide),were enhanced in growth of seminal and adventitious roots,as compared to thecnotrols, both at optimum (24℃-26℃) and chilling (10℃ - 15℃) temperatureregimes. However,at 15 mg/L and 20 mg/L concentrations,the responses of root growthto Mefluidide was shown to vary with variety. Concommitantly,higher levels of ethyleneevolution were detected in 5 mg/L and 10 mg/L Mefluidide-treated seedlings than in thecontrols.The germinating seeds of corn were exposed to an environment of exogenousethylene at very low concentrations (2 nl/ml 、4 nl/ml and 6 nl/ml), and experimentswere held at two temperature regimes of 10℃-15℃artd 24℃-26℃,seminal root extention of corn was enhanced by the presence of exogenous ethylene.These results directly proved that ethylene at very low concentrations has a physiological effect fo promoting root extension of plants, and also indirectly proved thatMefluidide inducing extremely low concentration evolution of ethylene from plants is thereason of enhancing extension of seminal and adventitious roots. In view of the abovementioned results and effects of Mefluidide on other endogenous hormones, We inferthat the action mode of Mefluidide at the cellular and molecular levels is related to its interfering in the metabolism of endogenous hormones which in turn changes a wholechain of events in plant cells.