土壤水分对强筋小麦‘豫麦34’氮素同化酶活性和籽粒品质的影响

 以强筋型小麦(Triticum aestivum)品种‘豫麦34号’为材料，采用盆栽方法研究了土壤水分对氮素同化酶活性及籽粒品质的影响。结果表明：旗叶硝酸还原酶（NR）活性于花后呈下降趋势，且土壤含水量为田间持水量（FC）60%的处理活性最强，其次为40%FC，活性最低的是80%FC。旗叶和籽粒中谷氨酰胺合成酶（GS）活性于开花15 d前均呈下降趋势，15 d后均为上升趋势，各水分处理间酶活性大小关系是：80%FC＞60%FC＞40%FC。各水分处理间旗叶和籽粒谷氨酸合成酶（GOGAT）活性的大小关系同GS。60%FC籽粒产量及品质最优，80%FC产量次之，40%FC产量最低；40%FC品质次之，80%FC品质最低。不同水分处理下籽粒蛋白质含量与叶片NR、GS 和籽粒GOGAT活性均呈正相关，与旗叶GOGAT活性呈负相关。且40%FC和80%FC下籽粒蛋白质含量只与旗叶GS活性相关性达显著水平, 60%FC下蛋白质含量则与旗叶NR和籽粒GS活性均达显著相关，与旗叶GS活性达极显著相关。

EFFECT OF WATER CONTROL ON ACTIVITIES OF NITROGEN ASSIMILATION ENZYMES AND GRAIN QUALITY IN WINTER WHEAT

In order to understand the effects of soil water availability on nitrogen assimilation enzyme activity and grain quality in winter wheat cultivar, pot experiments were carried out at the Henan Agricultural University Research Station during 2001-2003. Soil containing 9.8 g?kg-1 organic matter, 0.986 g?kg-1 total N, 25.43 mg?kg-1 olsen-P and 259 mg?kg-1 NH4OAc-K were used for the experiments. 18 kg of sieved soil was placed in each 30 cm × 40 cm pot. ‘Yumai 34’, a strong gluten cultivar, was used in the experiments. Three water treatments were used: soil water content of 60% field capacity (FC), 40% FC and 80% FC. All pots were under a rain-shelter, and water levels were controlled from elongation stage to harvest. Water content was measured by weight every two days. Before sowing, 3.5 g N, 3.3 g K2O and 2.9 g P2O5 were applied to each pot and a further 1.6 g N was applied to each pot during the elongation stage. Seven plants from each pot were selected when plants had five leaves. The experiment was arranged in a completely randomized design with ten replications per treatment, and all pots were managed in the same way. The results indicated that nitrate reductase (NR) activity in the flag leaf declined after anthesis in a decreasing order of 60%FC >40%FC >80%FC. Glutamine synthetase (GS) activity in both the flag leaf and grain all declined from the beginning of anthesis to 15 days after anthesis and then increased with the order among the three water treatments as follows: 80%FC＞60%FC＞40%FC. A similar pattern was found for glutamate synthase (GOGAT) as for GS. The highest grain yield and the best nutritional quality occurred in the 60%FC treatment whereas the 80%FC treatment had the lowest quality and 40%FC had the lowest grain yield. Grain protein content was positively correlated to NR and GS activity in flag leaves and GOGAT activity in the grain, and was negatively correlated to GOGAT activity in the flag leaves for all water treatments. In the 40%FC and 80%FC treatments, there was a significant correlation between grain protein content and GS activity in flag leaves. In the 60%FC treatment, there were significant correlations between grain protein content and NR activity in flag leaves and GS activity in grain, and grain protein was closely correlated to GS activity in flag leaves.