摘要
2017～2019年在盆栽条件下,以抗旱型小麦品种'济麦22'('JM22')和水分敏感型品种'临麦2号'('LM2')为材料,研究了挑旗至成熟期干旱对茎鞘贮藏糖代谢的影响及其与植株抗性和产量的关系.结果表明,干旱使'JM22'和'LM2'产量分别下降12.8％和36.6％,提高了小麦茎鞘贮藏物质对籽粒的贡献率;胁迫2～5 d后,SST和FFT活性受到抑制,FEH活性提高,DP≥4果聚糖和可溶性总糖含量下降,但DP=3果聚糖含量上升;胁迫后5～10d茎鞘内糖含量与对照差异变小,'JM22'糖含量提高值大于'LM2';干旱提高了'JM22'胁迫后15～31 d茎鞘内SST和FFT活性,促进了DP≥4和DP=3果聚糖的积累.干旱提高了两品种灌浆后期FEH活性,促进了果聚糖的转化输出.干旱发生后旗叶内的H2O2和O2-的积累量,MDA含量,SOD和CAT活性短时间内快速升高,但随胁迫时间的延长而下降;加速了灌浆后期旗叶H2O2和O2-的积累,MDA含量,SOD和CAT活性地升高.
Abstract
Under potted condition,two winter wheat cultivars,the drought-resistant wheat variety,'Jimai 22'('JM22'),and the water-sensitive wheat variety,'Linmai 2'('LM2'),were chosen to study the effects of drought stress on the metabolism of fructose in wheat stem and sheath from flag leaf stage to ripening stage,and its relationship with drought resistance and grain yield.The results showed drought decreased the yields of'JM22'and'LM2'by 12.8％and 36.6％,and increased the contribution rate of the dry matter stored in the stem and sheath to the grains of the wheats.During the 2nd to 5th day of drought stress,su-crose:sucrose fructosyltransferase(SST)and fructan:fructan fructosyltransferase(FFT)activity of the stem and sheath were inhibited,while fructan exohydrolase(FEH)activity was increased.At the same time,the content of fructose with polymerization(DP)≥4 fructose,and total water-soluble sugar(WSC)decreased,but the content of fructose with DP=3 increased;During the 5th to 10th day of drought stress,the contents of fructan and WSC in the stem and sheath were recovered,but the recovery magnitude of'JM22'was much greater than that of'LM2'.During the 15th to 31st day of drought resistance,drought en-hanced the activity of SST and FFT in the stem and sheath of'JM22',which promoted the accumulation of fructose with DP≥4 and DP=3.The activity of FEH of both wheat cultivars were much higher under drought condition than control during in the later stage of grain filling,which benefited the transform and output of fructan.The accumulation of H2O2 and O2-,content of MDA,the activity of SOD and CAT in wheat flag leaf increased rapidly at beginning of drought resistance,but they gradually recovered as the drought resis-tance persisted.The accumulation of H2O2 and O2-,the content of MDA,and the activity of SOD and CAT were enhanced under drought resistance at the late stage of grain filling.
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