氮素水平对不同氮效率基因型水稻的物质生产与分配的影响

EFFECTS OF NITROGEN LEVELS ON DRY MATTER ACCUMULATION AND DISTRIBUTION IN RICE GENOTYPE WITH DIFFERENT NITROGEN USE EFFICIENCIES

研究了在群体水培条件下,3种氮素水平(5、15和25mg.kg-1)对6种不同氮效率利用基因型迟熟中粳水稻物质生产与分配的影响。结果表明:氮素水平、基因型对水稻氮素干物质生产效率(NUEdm)、氮素籽粒生产效率(NUEg)均有极显著的影响。6种不同氮效率基因型可分成氮高效和氮低效利用型2类。NUEdm在2类基因型水稻中总体上均随着氮素水平升高呈现上升趋势;而NUEg在氮低效基因型中表现为随氮素浓度升高而先升后降。在水稻的4个关键生育期,不同氮素水平、2类基因型之间水稻干物质积累量差异显著。成熟期,氮素水平对水稻茎鞘、根、穗的干物质分配比例影响显著,对叶片干物质分配比例影响不显著。相同氮素水平下,就平均值而言,水稻茎鞘、叶片、根系干物质比例均表现为氮低效基因型>氮高效基因型,而穗的干物质比例均表现为氮高效基因型>氮低效基因型。氮素水平对不同基因型水稻产量影响显著,同一氮素水平下均表现为氮高效型基因型水稻产量显著高于氮低效型基因型,且施氮量越大差异越大。相关分析表明,水稻各关键生育期的干物质生产量、产量、每穗粒数均与氮素水平、基因型的NUEg、NUEdm显著或极显著相关,与成熟期水稻各器官干物质分配比例相关性则相对较弱。

Under hydroponic group conditions, six typical rice genotypes were selected to investigate the characteristics of dry matter accumulation and distribution under three nitrogen levels of 5,15 and 25mg· kg^-1 Nitrogen use efficiency for dry matter （NUEdm） and nitrogen use efficiency for grain yield （NUEg） were obviously different between different rice genotypes under three N levels. And then, six different nitrogen efficiency genotypes can be classified into two types of nitrogen- efficient and nitrogen inefficient. NUEdm increased with the nitrogen levels. Whereas, NUEg firstly increased and then decreased with the increase of nitrogen. At the four critical stages, there are significant differences in dry matter accumulation between two NUE types of rice genotypes under different N levels. At maturing stage, the ratios of culm and sheath, root, panicle dry weight to entire plant dry matter accumulation were significantly affected by N levels. At the same level of nitrogen, the average ratios of culm and sheath, root and leaves dry weight to entire plant dry matter accumulation were higher in N- inefficient genotype than that in N-efficient genotype. On the contrary, the ratio of panicle dry weight to entire plant dry matter accumulation was higher in N-efficient genotype than that in N-inefficient genotype. Significant effects of nitrogen levels were observed on the rice yield between different NUE types. N-efficient rice yields were higher than nitrogen-inefficient at the same nitrogen level. What＇ s more, with the nitrogen level increasing, the difference of yield was more obviouser. Each organ proportion was relatively weak correlation with NUE. Correlation analysis also demonstrated that the dry matter accumulation at four critical stages of rice, the yield and the grain numbers per panicle were significantly correlated with the NUEg and NUEdm between different NUE types under different N levels.