Abstract:

【Objective】In order to reveal the features of the source-sink in N-efficient rice,【Method】we conducted two experiments from 2012 to 2014 in paddy fields. A chromosome single segment substitution lines (CSSSLs) consisted of 114 rice lines were cultured in 2012 and 2013. On the basis of plant nitrogen accumulation per area and yield per area at maturity, the rice cultivars were clustered into six types by MinSSw (Minimum Square Sum Within Groups) method. We selected two lines, one is featured with high nitrogen accumulation and high yield (L68, nitrogen-efficient), the other with low nitrogen accumulation and low yield (L2, nitrogen-inefficient). The effects of nitrogen application levels on yield and source-sink characters were studied. 【Result】1) There was a significant difference among all tested lines in N accumulation per unit area and yield per unit area, the variation of N accumulation per unit area ranged from 11.53 to 27.66 g/m², the variation of yield per unit area from 311.74 to 763.35 kg/666.7 m². With the increase of nitrogen accumulation, grain yield tended to increase, but nitrogen accumulation types and the yield types were not completely similar. High nitrogen accumulation is an important basis of high yield, but yield was also affected by other factors; 2) The LAI at heading stage (including valid, efficient and total LAI) and mature stage of the N-efficient rice were higher than that of the N-inefficient. The green leaf weight which is the components of leaf area of N-efficient rice was higher than that of N-inefficient rice, but the specific leaf weight had little difference in different N-efficiency rice. 3) The storage capacity per unit area and spikelet number per unit area of N-efficient rice were higher than those of N-inefficient rice. The storage capacity per unit dry weight, storage capacity per unit leaf area, storage capacity per unit nitrogen absorption of N-efficient rice were large, and their ability of developing storage capacity was strong; 4) The spikelet numbers per unit leaf area, grain yield per unit leaf area and net assimilation rate at seed setting stage of N-efficient rice were large, and their “flux” was fluent and the photosynthetic capability was strong; 5) Comprehensive analysis shows that, the storage capacity had a large influence on the nitrogen efficient absorption, and the increasing storage capacity per unit nitrogen absorption contributed to increase in the storage per unit area. Under different nitrogen application levels, the LAI, storage capacity, N absorption and yield of N-efficient rice were higher than those of N-inefficient rice significantly. Under low nitrogen level, the LAI difference between two different N efficiency rice was maximum, nevertheless the differences of the other three indicators were larger under condition of low and medium nitrogen. 【Conclusion】The source-sink properties of N-efficient rice are better than other types at different N application levels.

Key words: N-efficient rice, N application level, N accumulation, yield, source-sink

摘要：

【目的】 本研究皆在阐明氮高效水稻源库性状的基本特点。【方法】 在大田条件下,于2012–2014年设计了两个试验。2012年和2013年,以染色体单片段代换系遗传群体114个水稻株系为供试材料,依据成熟期吸氮量和产量两个性状将114个株系群体分为6种不同氮效率类型。2014年,在前2两年试验的基础上,以筛选出的氮高效株系（L68）和氮低效株系（L2）为供试材料,研究施氮量对两种氮效率水稻株系产量、源库性状的影响。【结果】1）114个株系群体成熟期吸氮量和产量差异均较大,吸氮量变幅为11.53~27.66 g/m²,产量变幅为311.74~763.35 kg/666.7 m²,随着吸氮量的增加,产量呈上升趋势。产量类型与吸氮量类型并不完全一致,高吸氮量是高产的重要基础,但产量还可能受到其他因素的影响;2）氮高效水稻抽穗期叶面积系数（包括有效叶面积、高效叶面积、总叶面积）、成熟期叶面积系数均显著大于氮低效水稻,叶面积构成因子中氮高效水稻绿叶质量明显高于氮低效水稻,但比叶重不同氮效率品种间差异较小;3）氮高效水稻单位面积库容量、单位面积颖花量显著高于氮低效水稻,氮高效水稻单位干质量、单位叶面积和单位氮素库容量大,库容形成能力强;4）氮高效水稻单位叶面积颖花数、单位叶面积籽粒产量大,结实期净同化率高,氮高效水稻“流”畅,叶片光合能力强;5）综合分析表明,库容量对氮素高效吸收影响较大。提高单位氮素库容量有助于提高单位面积库容量。不同施氮水平下,氮高效水稻叶面积系数、库容量、吸氮量和产量均明显高于氮低效水稻,叶面积系数在低氮水平下两者差异最大,其他3个指标以低、中氮差异较大。【结论】氮高效水稻源库指标均优于其他类型,且这一优势在不同施氮量亦是如此。

关键词: 氮高效水稻, 施氮量, 吸氮量, 产量, 源库