不同氮敏感性粳稻品种的氮代谢与光合特性比较

本文旨在探明不同氮敏感性粳稻品种氮代谢与光合特性。以2个氮敏感高产品种淮稻5号和连粳7号,2个氮钝感品种宁粳1号和扬粳4038为材料,设置0和200 kg hm–2 2个施氮水平,研究其产量、氮肥利用效率以及地上部生理性状的变化特点。结果表明,在2种施氮水平下,氮敏感品种的产量和氮肥利用效率显著高于氮钝感品种。与氮钝感品种相比,氮敏感品种具有较高的光合速率和氮素积累,较强的氮代谢酶活性和较高的光合氮素利用效率,抽穗期茎叶中积累较多的可溶性糖和淀粉,抽穗至成熟期茎鞘中非结构性碳水化合物向籽粒转运率较高。表明氮敏感品种在较低施氮量下具有较高的生理活性和物质生产效率;这些特征可作为筛选高产氮敏感水稻品种的重要生理指标。

Comparison in Nitrogen Metabolism and Photosynthetic Characteristics between Japonica Rice Varieties Differing in Nitrogen Sensitivity

Understanding the physiological characters associated with nitrogen (N) use efficiency (NUE) is very important in selecting and breeding N-efficient varieties. However, the information on such characters is very limited. Four japonica rice varieties, i.e., two nitrogen sensitive varieties, Huaidao 5 (HD-5) and Lianjing 7 (LJ-7), two nitrogen insensitive varieties, Ningjing 1 (NJ-1) and Yangjing 4038 (YJ-4), were grown in the field, and two N rates, 0 and 200 kg ha^-1, were applied during the growing season. The yield components, NUE and aboveground physiological characters were investigated. The nitrogen sensitive varieties produced higher grain yield, exhibited higher NUE than nitrogen insensitive varieties at N rates of 0 and 200 kg ha^-1. When compared with the nitrogen insensitive varieties, the nitrogen sensitive varieties had a higher photosynthetic rate and N accumulation, stronger activity of the enzymes involved in N metabolism, higher photosynthetic NUE, more accumulation of soluble sugars and starch in stems and sheaths at heading time, and more remobilization of nonstructural carbohydrate from stems to grains during grain filling. These physiological traits resulting in higher grain yield and nitrogen use efficiency are important and can be used as physiological indexes to select and breed high-yielding and N-sensitive rice varieties.