花后高温和水分逆境对小麦籽粒蛋白质形成及其关键酶活性的影响

Effects of Post-Anthesis High Temperature and Water Stress on Activities of Key Regulatory Enzymes Involved in Protein Formation in Two Wheat Cultivars

以2个蛋白质含量不同的小麦品种扬麦9号和豫麦34为材料,在人工气候室条件下研究了花后高温和水分逆境对小麦籽粒蛋白质合成关键酶活性及籽粒蛋白质组分含量的影响。结果表明,籽粒蛋白质及其组分含量显著受温度、水分和温度×水分互作的影响,且温度的影响大于水分及温度×水分效应。高温提高了籽粒蛋白质含量,但降低了谷/醇比。无论高温或适温下,干旱胁迫均提高籽粒蛋白质含量。谷/醇比在适温干旱下升高,高温干旱下降低;渍水降低籽粒蛋白质含量和谷/醇比。籽粒蛋白质含量在高温干旱下最高,适温渍水下最低。在温度和水分逆境下,籽粒醇溶蛋白和谷蛋白的变化是导致蛋白质含量和谷/醇比差异的主要原因。高温和水分逆境均降低旗叶谷胺酰氨合成酶(GS)和籽粒谷-丙转氨酶(GPT)活性,不同温度条件下酶活性均表现为对照>干旱>渍水。高温和水分逆境对蛋白质合成关键酶活性的影响在不同品种间存在差异,适温下,豫麦34旗叶GS活性易受水分的抑制;扬麦9旗叶GS活性易受高温的抑制。高温下,豫麦34旗叶氮代谢受高温影响较大,而扬麦9则更易受水分胁迫影响。

Temperature and water are the main climatic factors affecting grain quality in wheat （ Triticum aestivum）. The growth-chamber experiments were carried out to investigate the effects of high temperature and water stress conditions during grain filling on the activities of key regulatory enzymes for protein accumulation and contents of protein components in wheat grains. Two wheat cultivars Yangmai 9 with low protein content and Yumai 34 with high protein content were grown under two day/night temperature regimes of 32℃/24℃ and 24℃/16℃ , respectively. For each temperature regime, three soil water levels were established as moderate water status （soil relative water content, SRWC = 75% - 80%）, drought （SRWC = 45% -50% ）, and waterlogging. The results showed that protein and protein component contents in grains were affected significantly by high temperature, water, and temperature x water. High temperature enhanced protein content, but reduced glutenin/gliadin ratio. Under both optimum temperature and high temperature, drought enhanced protein content. Drought enhanced glutenin/gliadin ratio under optimum temperature, but reduced it under high temperature. Under both high and optimum temperatures, waterlogging reduced protein content and glutenin/gliadin ratio. Protein content was the highest at high temperature x drought, and the lowest at optimum temperature x waterlogging. Under high temperature and water stresses, differences in protein content and glutenin/gliadin ratio were caused mainly by changes in gliadin and glutenin contents. Both high temperature and water stress reduced glutamine synthase （GS） activity in flag leaves and glutamate pyruvic amino transferase （GPT） activity in grains, and both enzymes in the treatments were CK 〉 drought 〉 waterlogging. The responses of GS and GPT activities to high temperature and water stress differed between two cuhivars with different grain protein contents. Under optimum temperature, GS activity in flag leaves was more affected by water stress for Yumai 34 and was more inhibited by high temperature for Yangmai 9. Opposite trend was found under high temperature.