摘要： 研究低温胁迫对不同抗倒春寒能力小麦品种幼穗结实性和生理特性的影响，分析抗倒春寒能力不同的小麦品种对低温胁迫的生理响应机制，为小麦抗倒春寒研究和品种改良提供理论参考。以2个小麦品种矮抗58（抗倒春寒）和郑麦366（不抗倒春寒）为材料，采用盆栽和人工模拟倒春寒处理的方法，分析研究了小麦雌雄蕊原基分化期、药隔分化期和四分体形成期0℃低温处理下小麦的结实特性和幼穗生理指标变化。结果表明，在雌雄蕊原基分化期、药隔分化期、四分体形成期进行低温处理，随处理时间的延长，2个参试品种的穗粒数均降低，但不同处理时间和品种间穗粒数降低幅度不同。雌雄蕊原基分化期低温胁迫处理24，48，72 h后，矮抗58穗粒数分别下降了6.52%，14.07%，22.37%，郑麦366穗粒数下降了37.14%，44.43%，64.71%；药隔分化期低温处理24，48，72 h后，矮抗58穗粒数分别下降了3.74%，9.05%，13.71%，郑麦366穗粒数下降了27.54%，37.80%，48.55%；四分体形成期低温处理24，48，72 h后，矮抗58穗粒数分别下降了2.70%，4.70%，4.73%；郑麦366分别下降了12.39%，29.67%，32.30%。随着低温处理时期的延迟，矮抗58、郑麦366的穗粒数降幅均表现下降的趋势。雌雄蕊原基分化期低温处理穗粒数下降最明显，说明雌雄蕊原基分化期对低温较敏感。矮抗58、郑麦366幼穗雌雄蕊原基分化期、药隔分化期低温处理72 h内，2个参试品种幼穗的可溶性糖和可溶性蛋白质含量总体上均呈先升高后缓慢降低的趋势。矮抗58的可溶性蛋白质和可溶性糖含量及上升幅度均大于郑麦366。低温处理后，2个小麦品种幼穗超氧化物歧化酶（SOD）、过氧化物酶（POD）、过氧化氢酶（CAT）活性升高且均高于对照，但随着低温处理时间的延长稍有下降，其中矮抗58幼穗中SOD、POD、CAT活性和上升幅度均高于郑麦366，并且丙二醛（MDA）含量的增幅小于郑麦366。相关分析结果表明，低温胁迫后，小麦穗粒数与SOD活性、POD活性分别呈显著、极显著正相关，与MDA含量呈极显著负相关。POD活性、SOD活性、MDA含量可作为小麦幼穗抗倒春寒特性的评价指标，小麦抗倒春寒的生理机制表现为多方面的综合防御。

关键词: 小麦, 幼穗, 穗分化, 低温处理, 结实性, 生理特性

Abstract: Aikang 58 and Zhengmai 366 were taken as the materials to study the effects of low temperature stress on seed setting and physiological characteristics of wheat varieties with different resistances to spring chill, in order to provide the theoretical reference for further research of wheat resistance to late spring coldness and variety improvement. The pot culture and artificial simulation method for late spring coldness were used to analyze the seed setting characteristics and the change of young ear physiological indexes at female stamen primordium differentiation stage, anther separation stage and tetrad formation stage of wheat under treatment of 0℃ low temperature. The results showed that the grain number per ear of the two tested varieties decreased with the extension of the low temperature treatment time for all the three treatment stages, but the degrees of decrease were different in different treatment times and varieties. After 24, 48 and 72 h of low temperature stresses at stamen/pistil differentiation stage, the grain number per panicle of Aikang 58 decreased by 6.52%, 14.07% and 22.37%, while that of Zhengmai 366 decreased by 37.14%, 44.43% and 64.71%, respectively. After 24, 48 and 72 h of low-temperature treatments at anther separation stage, the grain number per ear of Aikang 58 decreased by 3.74%, 9.05% and 13.71%, and that of Zhengmai 366 decreased by 27.54%, 37.80% and 48.55%, respectively. After low temperature treatments for 24, 48, and 72 h at tetrad formation stage, the grain number per spike of Aikang 58 decreased by 2.70%, 4.70%, and 4.73%, but that of Zhengmai 366 decreased by 12.39%, 29.67% and 32.30%, respectively. With the delay of low temperature treatment time, Aikang 58 and Zhengmai 366 both showed a decreasing trend in grain number per panicle. The number of grains per spike decreased significantly in low temperature treatment at female stamen primordium differentiation stage, indicating that this stage was sensitive to low temperature. The contents of soluble sugar and soluble protein in young panicles of Aikang 58 and Zhengmai 366 showed a trend of increasing first and then slowly decreasing after the low temperature treatments for 0, 24, 48 and 72 h at female stamen primordium differentiation stage, anther separation stage and tetrad formation stage. The absolute contents and rising trends of soluble protein and soluble sugar in Aikang 58 were higher than in Zhengmai 366. After low temperature treatment, the superoxide dismutase(SOD), peroxidase activity(POD)and catalase activity(CAT)of the two varieties were all higher than those of the control, while the absolute levels and increasing trends of SOD, POD and CAT in young ears of Aikang 58 were all higher than in that of Zhengmai 366, but the increasing level of malondialdehyde(MDA)in Aikang 58 was lower than in Zhengmai 366. The correlation analysis showed that grain number per panicle had significant or extremely significant positive correlations with SOD activity and POD activity, and extremely significant negative correlation with MDA content after low temperature stress. POD, SOD and MDA could be used as the evaluation indexes of wheat seedling resistance to spring chill. The physiological mechanism of wheat resistance to spring chill is manifested as a comprehensive defense in many aspects.

Key words: Wheat, Young spike, Spike differentiation, Low temperature treatment, Seed setting characteristics, Physiological characteristics

中图分类号: 

• S512.1