水旱条件下小麦不同抗旱性品种籽粒蛋白质积累的差异及施氮量的调控效应

在水、旱两栽培条件下比较了农大189 (不抗旱品种)和晋麦47 (抗旱品种)的籽粒蛋白质积累及施氮的调控效应。与灌溉条件相比，旱地栽培提高了籽粒清蛋白、醇溶蛋白、谷蛋白、总蛋白含量及谷/醇比，降低了球蛋白含量。旱作对农大189的籽粒蛋白质组分含量有显著影响，而对晋麦47籽粒球蛋白、醇溶蛋白、总蛋白、谷/醇比的影响不显著。旱作降低了籽粒谷氨酰胺合成酶(GS)、籽粒谷氨酸合酶(GOGAT)、籽粒谷丙转氨酶(GPT)、旗叶谷氨酰胺合成酶(GS)、旗叶谷氨酸合酶(GOGAT)活性，且影响了籽粒GPT活性的变化趋势。旱作对蛋白质合成有关酶活性的影响表现为农大189大于晋麦47。随着施氮量的增加，籽粒蛋白质及其组分含量表现为增加趋势，且施氮的调控效应对晋麦47大于对农大189。不同栽培条件下各处理的籽粒GS、籽粒GOGAT、籽粒GPT、旗叶GOGAT活性与籽粒蛋白质产量呈显著正相关，而与籽粒蛋白质含量无显著相关。两品种旗叶GS活性与蛋白质产量的相关性不同。总之，抗旱品种的籽粒蛋白质积累受水分条件影响小于不抗旱品种，表现一定的抗旱能力；施用氮肥可提高籽粒蛋白质含量，抗旱品种的氮肥调控效应大于不抗旱品种。

Protein Accumulation in Grains of Wheat Cultivars Differing in Drought Tolerance and Its Regulation by Nitrogen Application Amount under Irrigated and Dryland Conditions

The protein accumulation in wheat (Triticum aestivum L.) grains is seldom studied under dryland condition although it has been widely tested under irrigated conditions. For understanding the protein accumulation characteristics of wheat cultivars differing in drought tolerance and the effects of water and nitrogen, a drought-tolerant cultivar, Jinmai 47, and a drought-sensitive cultivar, Nongda 189, were planted under both irrigated and dryland conditions with three nitrogen application rates. From the 5th day after anthesis, spikelets and flag leaves were sampled at a 5 days interval for measuring the contents of protein and its components in grains and the enzymes activities in grains and flag leaves. The results indicated that the contents of albumin, gliadin, glutenin, total protein, and the ratio of glutenin to gliadin in dryland cropping were higher than those in irrigated cropping, but the globulin content was lower than that in irrigated cropping. For Nongda 189, the contents of protein and its components and the ratio of glutenin to gliadin in grains were affected significently by drought, whereas for Jinmai 47, the variations on contents of globulin, gliadin, total protein, and ratio of glutenin to gliadin were slightly. The activities of glutamine synthetase (GS), glutamate synthase (GOGAT), glutamic acid-pyruvate transaminase (GPT) in grains and the activities of GS and GOGAT in flag leaves were reduced in dryland cropping compared with those in irrigated cropping. Simultaneously, the trend of GPT activity in grains was also affected by dryland cropping. The effect of drought on activities of these enzymes that involved in protein accumulation was greater in Nongda 189 than in Jinmai 47. Nitrogen application promoted the contents of protein and its components in grains, and higher rate of nitrogen application resulted in greater positive effect. Jinmai 47 presented greater effect of nitrogen application on protein content in grains than Nongda 189. Under both growing conditions, the activities of GS, GOGAT, and GPT in grains and the activity of GOGAT in flag leaves in all nitrogen treatments significantly correlated with the protein yield rather than the protein content in grains. The correlation between GS activity in flag leaves and protein yield in grains was different in the two cultivars. The above results suggest that the drought-tolerant cultivar is less affected by water condition compared with the drought-sensitive cultivar; application of nitrogen could promote the protein content in grains, and the effect is greater in the drought-tolerant cultivar than in the drought-sensitive cultivar.