Abstract:

Effects of methyl jasmonate (MeJA) on floret opening were investigated in male-sterile and male-fertile rice ( Oryza sativa subsp. indica ). Excised or intact panicles with several top florets flowered one day before the experiments were soaked in MeJA, salicylic acid (SA), 24-epibrassinolide (24-epiBL) or control solution for 2 min. MeJA at the concentration of 4 mmol/L significantly promoted rice floret opening; the response of floret opening of male-sterile rice to MeJA was more sensitive than that of male-fertile rice (such as maintenance line and conventional variety). The percentage of finally opened-floret per panicle of Zhenshan 97A (cytoplasmic male sterile line) or Pei'ai 64S (thermo-sensitive genic male sterile line) treated with MeJA was over 40% in the day of experiment, that of Zhenshan 97B (maintenance) and Pei'ai 64 (conventional variety) was (21±1.5)% and (25±2.1)%, respectively; floret opening of intact Pei'ai 64S panicles in the field could also be induced by 2-mmol/L MeJA. The percentage of opened floret in all control panicles was 0% or less than 5% in the day of experiment. The percentage of fertilized-grain of Zhenshan 97A and Longtepu A could be increased over 24% by spraying panicles with 2-mmol/L MeJA solution （circa 6.0 μmol per panicle）. The lag time (time from the finishing of treatment to first floret opening) of male sterile line responsing to MeJA was 10 min shorter than that of male fertile line. MeJA induction on the rice floret opening could markedly be inhibited by SA solution at the concentration of 1 mmol/L, and the inhibition of SA on MeJA induction on floret opening of male-sterile rice could be nullified by MeJA treatment again. MeJA effect on floret opening of male-sterile rice could be clearly synergized by pretreatment with 24-epibrassinolide (24-epiBL).

雄性不育和可育水稻开颖对茉莉酸甲酯响应的差异
宋 平1,2* 夏凯1 吴传万1  包冬萍2  陈丽莉2 周燮1  曹显祖2

（1. 南京农业大学农学系，南京210095；2. 扬州大学农业部江苏省作物栽培生理重点开放实验室，扬州225009）

摘要：以水稻(Oryza sativa subsp.indica)雄性不育系和可育系为材料，在室内用溶液浸已开过一天花的水稻离体穗2min，发现4mmol/L茉莉酸甲酯（MeJA）能显著诱导水稻开颖，且MeJA诱导水稻雄性不育材料开颖的效应明显强于可育材料（如保持系和常规品种），MeJA使雄性不育系珍汕97A、温敏雄性核不育系培矮64S的当天最后开颖率达到40%以上，保持系珍汕97B、常规品种“培矮64”的当天最后开颖率仅有(21±1.5)%、(25±2.1)%，对照穗在当天始终不开颖或开颖极少（<5%）；不育系开颖对MeJA响应的滞后期比可育系短10min左右。在田间，2mmol/LMeJA溶液浸或喷雾水稻连体穗，也同样能明显提高培矮64S的开颖率；辅以人工授粉，MeJA能大幅度提高珍汕97A、龙特浦A的结实率（提高24%以上）。1mmol/L水杨酸（SA）能抑制MeJA诱导水稻开颖，而MeJA的再次处理能解除SA对MeJA诱导雄性不育系开颖的抑制效应，SA抑制MeJA诱导保持系开颖的效应不能被再次使用MeJA所解除。24-表油菜素内酯（24-epiBL）预先处理能显著增强MeJA诱导不育系开颖，而对于保持系，此效应不明显。

关键词： 水稻雄性不育系；保持系；开颖；茉莉酸甲酯；水杨酸；24-表油菜素内酯

Key words: male-sterile rice, maintenance line, floret opening, methyl jasmonate (MeJA), salicylic acid (SA), 24-epibrassinolide (24-epiBL)