水稻产量对氮肥响应的品种间差异及其与根系形态生理的关系

摘要

以籼稻天优华占、两优培九和粳稻陵香优18、宁粳1号为材料,研究了水稻产量对氮肥的响应。结果表明,水稻产量对施氮量的反应存在明显的品种间差异。上述4个水稻品种在获得最高产量(10.1~10.3 t hm–2)时,天优华占和陵香优18所需施氮量为242.5~255.5 kg hm–2,明显低于两优培九和宁粳1号的327.3~328.0 kg hm–2。天优华占和陵香优18的氮肥农学利用率和氮肥偏生产力均明显高于两优培九和宁粳1号,表明天优华占和陵香优18产量对氮肥的反应较两优培九和宁粳1号敏感。在高产(10.5~10.9 t hm–2)条件下,天优华占和陵香优18主要生育期根系的重量、长度和总吸收表面积低于两优培九和宁粳1 号,而根系活跃吸收表面积及其占总吸收表面积的比例、根系伤流量以及根系活力则显著高于两优培九和宁粳1 号。上述结果表明,通过栽培措施调控或选用根系活跃吸收表面积、根系伤流量和根系活力高的水稻品种将更有利于降低水稻施氮量和提高产量及氮肥利用效率。%Yield responses to nitrogen (N) rates in indica rice cultivars Tianyouhuazhan, Liangyoupeijiu and japonica rice culti-vars Lingxiangyou 18 and Ningjing 1 were investigated and showed significant differences among them. The optimal N rates in Tianyouhuazhan and Lingxiangyou 18 were only 242.5–255.5 kg ha–1, significantly lower than those in Liangyoupeijiu and Ning-jing 1 (327.3–328.0 kg ha–1), when the maximum grain yield (10.1–10.3 t ha–1) reached. The agronomic use efficiency and partial factor productivity of N fertilizer were much higher in Tianyouhuazhan and Lingxiangyou 18 than in Liangyoupeijiu and Ningjing 1, indicating that the yield is much more sensitive to N rate in the former two cultivars than in the latter two rice cultivars. Under high-yielding (10.5–10.9 t ha–1) conditions, root dry weight, root length and total root absorbing area at main growth stages were lower, but the root active absorbing area and its ratio to total root absorbing area, root bleeding sap and root activity were higher in Tianyouhuazhan and Lingxiangyou 18 than in Liangyoupeijiu and Ningjing 1. These results suggested that increasing root active absorbing area, root bleeding sap and root activity through the regulation of cultivation or breeding will be much more beneficial to decreasing N rate and increasing grain yield and N use efficiency in rice.