不同谷子品种萌发期对干旱胁迫生理响应的变化及抗旱指标筛选

Changes of Physiological Response to Drought Stress and Selection of Drought Resistance Indexes in Different Germination Stages of Millet

为了探讨干旱胁迫对谷子萌芽期的影响,筛选抗旱谷子新品种及谷子萌芽期抗旱性相关指标,明确干旱胁迫对不同谷子品种萌发期生理特征变化影响,以20%的聚乙二醇(PEG-6000)模拟干旱胁迫对15个谷子品种进行了萌发期抗旱性鉴定,对相关的六个抗旱性指标进行了筛选和相关性研究,并通过测定15个品种在干旱胁迫条件下SOD、POD和CAT的活性来研究其变化情况。结果表明:以萌发抗旱指数为标准指标,15个品种谷子萌发期抗旱性基本可以分为强、中、弱3类,其中抗旱性强的3个品种分别是陇谷10号、长生07、晋谷21号;抗旱性弱的2个品种是济谷20号、长生13。在干旱胁迫条件下谷子SOD、POD和CAT活性均有所升高,其中SOD活性在抗旱性强的3个品种中值最大,在抗旱性较弱的2个品种中值最小;SOD活性升高值与萌发抗旱指数显著正相关,而POD和CAT活性升高程度与萌发抗旱指数相关性不显著。通过相关性分析表明,活力抗旱指数、相对发芽率、相对发芽势与萌发抗旱指数呈极显著正相关,而相对胚芽长、相对胚根长与萌发抗旱指数之间没有明显的相关性。综上,在相关的六个抗旱性指标中,谷子抗旱的标准指标是萌发抗旱指数,谷子萌发期抗旱性鉴定的首要指标为活力抗旱指数和相对发芽率,次级指标则是相对发芽势,参考指标为相对胚芽长和相对胚根长。

In order to explore the effects of drought stress on the germination stage of millet, select new drought-resistant millet varieties and indexes related to drought resistance in the germination stage, this paper measured six indicators using 20% PEG-6000 to simulate drought stress of fifteen millet varieties for drought resistance evaluation, and studied the changes of SOD, POD and CAT activities under drought stress by measuring 15 varieties. Based on the sprout index of drought resistance, the drought resistance of 15 varieties of millet was divided into three categories: strong, medium and weak. Among them, the three varieties with strong drought resistance were Longgu 10, Changsheng 07 and Jingu 21;the two varieties with weak drought resistance were Jigu 20 and Changsheng 13. The activity of SOD, POD and CAT in millet all increased under drought stress. The SOD activity was the highest in the three varieties with strong drought resistance;and was the lowest in the two varieties with weak drought resistance. The increase of SOD activity was significantly positively correlated with the sprout index of drought resistance, while the increase of POD and CAT activity was not significantly correlated with the sprout index of drought resistance. The results of correlation analysis showed that vigor index of drought resistance, relative germination rate, relative germination vigor and sprout index of drought resistance were significantly positively correlated. There was no significant correlation between the relative plumule length and sprout index of drought resistance;and there was no significant correlation between relative radicle length and sprout index of drought resistance. Among the relevant six drought resistance indicators, the sprout index of drought resistance was used as the standard index for drought resistance of millet. In the remaining indicators, vigor index of drought resistance and relative germination rate could be used as the first indicator of drought resistance identification at millet germination stage;relative germination vigor could be used as the second indicator;relative plumule length and relative radicle length could be used as the reference index.