小麦/玉米萌发和苗期生长对干旱与低温的响应
The germination and seedling growth responses of wheat and maize to drought and low temperature
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摘要: 春旱和低温是影响东北作物生长的气候问题之一。以禾本科作物玉米和小麦为对象,模拟低温和干旱的单一及复合胁迫对其萌发和早期幼苗生长的影响。结果表明,低温和干旱,单一和复合胁迫均显著影响着小麦和玉米种子的萌发及早期幼苗生长。小麦幼苗在15 ℃~25 ℃和0~20%的PEG水平下,保持较高的萌发率(63.3%~87.3%),而在10 ℃和30%PEG浓度下显著下降,10 ℃和不同PEG浓度下以及30% PEG和不同温度处理下的萌发率区间分别为0~64.7%和0~18%。玉米种子在15 ℃~25 ℃和0~20%的PEG水平下,萌发率变化区间为2.22%~100%,在10 ℃和不同PEG浓度下以及30%的PEG处理在不同温度下的玉米种子萌发率均为0。小麦早期幼苗的长度和生物量变化趋势相似,随着干旱强度增加和温度的降低,先增加后降低,在10% 的PEG水平和20 ℃的气温条件下,其幼苗长度和生物量值最高。玉米幼苗的长度和干重与其萌发率变化趋势一致,显著线性下降,最高值出现在0%的PEG 水平和25 ℃的气温条件下。小麦幼苗的根冠比高于玉米。推测在较强的低温和干旱胁迫下,小麦比玉米具有更高的萌发和生长适应性。生物量向根部分布以及高根冠比值是小麦对干旱低温的适应性策略。Abstract: Spring drought and low temperature in northeast China are the main climate stresses influencing crop growth.In this paper,we selected two crops,wheat and maize,to simulate the effects of single and combined stresses of spring drought and low temperature on germination and early seedlings growth of the two crops.The results showed that,both single and their interaction would significantly influence the germination and early seedlings growth of wheat and maize.Wheat seeds maintained a higher germination percentage of 63.3%-87.3% with PEG under 15-25 ℃ and 0-20%,but sharply reduced by 30% with PEG under 10 ℃,respectively.The germination percentages with different levels of PEG under 10 ℃ and 30% PEG under different temperature levels were 0-64.7% and 0-18%,respectively.The germination percentage of maize seeds was 2.22%-100% with 0-20% PEG under 15-25 ℃,but the germination percentage was zero with 30% PEG under 10 ℃.The wheat length and biomass of early seedling changed in a similar trend to germination with increased drought and decreased temperature,and the peak value was obtained with 10% PEG under 20℃.The changes of maize seedling length and biomass were consistent with the germination change,and the peak value was obtained without PEG under 25℃.Root/shoot ratio of wheat was higher than that of corn,which indicated that wheat would germinate and grow better than corn under lower temperature and stronger drought.More root biomass and higher root/shoot ratio would be adaptive strategies for wheat seedlings to low temperature and drought stresses.