Free Polyamines in Grains in Response to Soil Drought and Their Relationship with Grain Filling of Wheat
ZHANG Wei-Yang;XU Yun-Ji;QIAN Xi-Yang;LI Yin-Yin;WANG Zhi-Qin;YANG Jian-Chang;Jiangsu Provincial Key Laboratory of Crop Genetics and Physiology, Co-innovation Center of Modern Production Technology for Grain Crops,Yangzhou University;
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 superior and inferior grains showed great decreases of grain-filling rate(20.5–28.8%) and grain weight(16.9–28.5%) after spraying MGBG under the three soil moistures. These results indicate that the responses of polyamines in grain to soil moisture vary with drought strength, and moderate drought stress has a positive effect on grain filling through increasing concentrations of Spd and Spm and the ratios of Spd/Put and Spm/Put in grains.
【Fund】： 国家自然科学基金项目(31271641 31471438);; 中央级科研院所基本科研业务费(农业)专项(201103003 201203079);; 国家科技支撑计划项目(2011BAD16B14 2012BAD04B08 2013BAD07B09 2014AA10AS605);; 江苏省农业三新工程项目(SXG2014313);; 江苏高校优势学科建设工程专项资助~~
【CateGory Index】： S512.1;S423
【CateGory Index】： S512.1;S423