Abstract:

Drought is one of the major agro-meteorological disasters to restrict the improvement of grain production and quality in China. The soil moisture and mineral elements affect alternately to the growth and development of winter wheat as well as the yield and quality. The response of leaves mineral elements accumulation, yield and grain quality of winter wheat to different grades drought stress was explored at the moisture critical period, which has a certain realistic significance to scientific fertilization and drought disaster prevention. At the moisture critical period (jointing to flowerings stage), the winter wheat ‘Qimai 2’ was used as material to set the water control experiments with five gradients (T1 treatment, soil moisture at 20 cm depth was suitable (60%-80%) in the whole period, and T2, T3 and T4 treatments were supplied once with water at 80%, 50% and 25% of 75.0 mm base recharge, respectively, while T5 treatment wasn’t supplied water)， the influences of drought stress on the accumulation of nitrogen, phosphorus and potassium mineral elements, photosynthetic pigments and photosynthetic parameters, yield and grain quality of winter wheat were simulated and analyzed. The results show that the total nitrogen, total phosphorus, photosynthetic pigment content and the maximum net photosynthetic rate (P_nmax), apparent quantum efficiency (AQE) and light saturation point (LSP) of winter wheat leaves were all the highest under T1 treatment during the water control to rewatering. Due to drought stress, the above-mentioned indicators reduced significantly under T2, T3, T4 and T5 treatments, and the heavier the drought stress, the greater the reduction was. Compared with T1 treatment, the total nitrogen, total phosphorus content, chlorophyll a, chlorophyll a+b, carotenoid content, P_nmax, AQE and LSP of leaves reduced by 1.68%, 0.15%, 0.90 mg·g^-1, 1.05 mg·g^-1, 0.21 mg·g^-1, 64.6%, 65.8% and 31.2% under T5 treatment, respectively. However, the total potassium content and light compensation point (LCP) of leaves increased with the aggravation of drought stress, and those under T5 treatment were 1.20% and 84.0% higher than under T1 treatment, respectively. In addition, the drought stress decreased significantly spike grains number, forming spike rate and thousand grains weight. Compared with T1 treatment, the theoretical yield and grain protein content decreased by 56.6% and 30.1%, respectively, while the grain starch content increased by 11.6% under T5 treatment.

Key words: winter wheat, water critical period, drought stress, mineral elements, yield, quality

摘要：

干旱是制约我国粮食产量和品质提升的主要农业气象灾害之一。土壤水分与矿质元素交互作用，共同影响冬小麦的生长发育及产量、品质，探究水分关键期冬小麦叶片矿质元素积累、产量和籽粒品质对不同程度干旱胁迫的响应，对科学施肥和干旱灾害防御具有现实意义。本文以冬小麦品种“齐麦2号”为试材，在水分关键期（拔节—扬花期）设计5个梯度的水分控制试验（T1处理为适宜水平，T2、T3、T4处理分别按照基准补水量75.0 mm的80%、50%、25%一次性补水，T5处理不补水），模拟研究水分关键期干旱胁迫对冬小麦叶片氮、磷、钾矿质元素积累和光合色素、光合参数以及产量和籽粒品质的影响。结果表明：水分控制期间至复水后，T1处理下冬小麦叶片全氮、全磷、光合色素含量及最大净光合速率（Maximum Net Photosynthetic Rate，P_nmax）、表观量子效率（Apparent Quantum Efficiency，AQE）、光饱和点（Light Saturation Point，LSP）均最高，受干旱胁迫影响，T2、T3、T4和T5处理下上述要素均显著降低，且干旱胁迫程度越重降低幅度越大，T5处理叶片全氮、全磷含量和叶绿素a、叶绿素a+b、类胡萝卜含量及P_nmax、AQE、LSP分别较T1处理降低1.68%、0.15%、0.90 mg·g^-1、1.05 mg·g^-1、0.21 mg·g^-1、64.6%、65.8%、31.2%，而叶片全钾含量、光补偿点（Light Compensation Point，LCP）则随干旱胁迫加剧而升高，T5处理分别较T1处理升高1.20%和84.0%；干旱胁迫还造成冬小麦穗粒数、成穗率、千粒重显著降低，T5处理理论产量和籽粒蛋白质含量分别较T1处理降低56.6%和30.1%，而籽粒淀粉含量较T1处理升高11.6%。

关键词: 冬小麦, 水分关键期, 干旱胁迫, 矿质元素, 产量, 品质