| 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). |
