花生种子萌发吸胀阶段冷害抗性的鉴定及耐冷种质的筛选

Identification of Imbibitional Chilling Injury Resistance for Peanut and Screening of Imbibitional Chilling-tolerance Germplasm

为更好地评价花生吸胀冷害抗性,本研究首先分析了常温条件下(25℃)和冷胁迫条件下(2℃)花生种子萌发过程中的吸水状况,结果表明不同基因型的花生吸胀阶段的持续时间基本一致,维持在浸种后0~12 h;冷胁迫能够使吸胀阶段初期的吸水速度显著下降,但对吸胀阶段的持续时间没有显著影响。对种子萌发3个生理阶段(吸胀、萌动、萌发阶段)分别进行冷害胁迫处理,结果表明吸胀阶段遭受的冷害胁迫对花生种子萌发影响较其他阶段严重。进一步的试验表明,吸胀阶段种子2℃冷胁迫12 h,能够更好地区分不同花生种质之间吸胀冷害抗性的差异,从而建立了花生种子吸胀冷害抗性的鉴定体系。利用该鉴定体系对64份花生种质的吸胀冷害抗性进行鉴定,以相对发芽率85%为阈值,筛选出了7份耐冷种质。本研究为花生耐冷育种及吸胀冷害抗性机制解析提供了技术鉴定体系和材料基础。

In order to better evaluate the imbibitional chilling injury resistance of peanut,we analyzed the water-uptake conditions during peanut germination under the normal temperature(25℃)and chilling treatment(2℃),respectively.The result revealed that the duration time for the imbibitional stage of peanut germination among different peanut genotype was consistent,lasting from 0-12 h after seed soaking.The chilling stress was found to slow down the speed of water-uptake at the early phase of imbibition stage;however,on visible difference on duration time was observed.The imbibitional chilling injury was found to be much more serious than chilling injury occurred at other stages during peanut germination.By further evaluating the effect of temperature and duration of imbibitional chilling injury on the germination rate,the results showed that 2℃/12 h was the most optimal condition to identify the imbibitional chilling injury resistance.By taking use of this method,sixtyfour peanut accessions were evaluated for their imbibitional chilling injury resistance.Seven accessions showed the relative germination rate over 85%under the imbibitional chilling stress,and they were considered as chillingtolerance accessions.Taken together,this study provided useful information for breeding new peanut varieties with chilling-tolerance and also for unlocking the mechanism for chilling response of peanut during imbibition.