中文摘要：

为探明干旱胁迫下小麦内源游离多胺在籽粒灌浆过程中的作用,2013—2014和2014—2015年度选用高产品种扬麦16和宁麦13进行不同水分条件的盆栽试验。自分蘖末期至成熟期设置正常供水（WW）、土壤轻度干旱（MD）和土壤重度干旱（SD）3种处理,观察不同土壤水分对籽粒中游离多胺和籽粒灌浆的影响。2个品种的结果一致表明,与WW相比,MD处理对叶片水势及光合作用没有显著影响,显著增加弱势粒灌浆速率（12.5%）和粒重（11.8%）,对强势粒灌浆无显著影响;SD处理则严重抑制叶片光合作用,显著降低叶片水势,强势粒的灌浆速率和粒重分别下降10.1%和9.5%,弱势粒的灌浆速率和粒重分别下降14.5%和11.7%。MD处理显著提高了灌浆期弱势粒中游离亚精胺（Spd）和精胺（Spm）含量及其与腐胺（Put）的比值,而SD处理的结果则相反。籽粒灌浆速率、粒重与籽粒中Spd和Spm含量及Spd/Put和Spm/Put值呈极显著正相关,与Put含量呈极显著负相关。喷施Spd和Spm,显著增加3个处理弱势粒及SD处理强势粒的灌浆速率（11.2%~25.9%）和粒重（9.9%~17.7%）,但对WW和MD处理的强势粒无显著影响;喷施Spd和Spm合成抑制剂[甲基乙二醛-双脒基腙（MGBG）]后,3个处理强、弱势粒的灌浆速率和粒重均显著降低,分别下降20.5%~28.8%和16.9%~28.5%。表明小麦籽粒中多胺对土壤水分的响应因土壤干旱程度而异,通过轻度土壤干旱处理增加籽粒中Spd和Spm含量以及Spd/Put和Spm/Put值,可以促进籽粒灌浆,增加粒重。

英文摘要：

For understanding the role of endogenous free polyamines on grain filling of wheat under drought stress, we conducted a two-year pot experiment from September 2013 to June 2015 using high-yield wheat cultivars Yangmai 16 and Ningmai 13 grown in different soil moisture conditions. Three treatments, namely well-watered（WW）, moderate soil-drought（MD）, and severe soil-drought（SD）, were imposed from late-tillering to maturity stage. Grain filling rate and free polyamines levels in both superior and inferior grains were determined. The results showed the consistency between the two cultivars. Compared with WW, MD treatment had significantly increased grain-filling rate and grain weight in inferior grains by 12.5% and 11.8%, respectively; whereas no effect on grain filling in superior grains. In contrast, SD treatment showed negative influences on leaf water potential, photosynthetic rate, and grain filling. Under SD treatment, grain-filling rate and grain weight of superior grains reduced by 10.1% and 9.5% and those of inferior grains reduced by 14.5% and 11.7%, respectively. During grain filling, concentrations of free spermidine（Spd） and spermine（Spm） as well as their ratios to putrescine（Put） in inferior grains increased significantly under MD treatment and decreased significantly under SD treatment. Grain-filling rate and grain weight were positively correlated with concentrations of Spd and Spm, and the ratios of Spd/Put and Spm/Put（P 0.01）, whereas negatively correlated with Put concentration（P 0.01）. Exogenous Spd or Spm resulted in significant increases of grain-filling rate（11.2–25.9%） and grain weight（9.9–17.7%） in inferior grains under the three soil moistures and in superior grains under SD treatment, and had no significant difference in superior grains between WW and MD treatments. The positive effects of exogenous Spd and Spm were eliminated when their synthesis inhibitor, methylglyoxal-bis guanylhydrazone（MGBG）, was applied together with Spd and Spm. Both s