不同基因型机插稻植株氮素积累运转特性

【目的】明确机械化育插秧条件下不同基因型水稻氮素吸收利用的特点,分析提高其氮素吸收利用的途径。【方法】以3个中籼中熟杂交稻、3个中籼迟熟杂交稻、4个粳稻共计10个品种为材料,采用随机区组大田试验设计,测定不同生育时期各器官干物重和氮素含量、产量等,研究了不同基因型机插稻植株氮素积累、分配和运转特性的差异及其原因。【结果】1)育插秧机械化条件下水稻植株氮素积累符合Logistic曲线增长规律。2)整个生育期机插稻植株含氮量呈下降趋势,粳稻植株的含氮量在生长中期(拔节期—抽穗期)高于杂交籼稻,而后逐渐降低,到成熟期极显著低于杂交籼稻,中籼中熟杂交稻因降低缓慢到成熟期植株含氮量最高。3)粳稻植株的终极氮素积累量最低,中籼中熟杂交稻和中籼迟熟杂交稻终极氮素积累量平均比粳稻高23.0%和33.1%。4)中籼中熟杂交稻抽穗期—成熟期氮素积累量最大,在氮素积累上具有后发优势,且穗部分配率、叶片与茎鞘氮素表观转运率、氮素籽粒生产效率和氮素转运效率均较高,说明育插秧机械化条件下,中籼中熟杂交稻品种的氮素在转运和利用上具有高效性。其中,F优498的终极氮素积累量高,且具有前期积累快,后期运转分配合理等优势。5)中籼迟熟杂交稻氮素积累出现最大增长速率较晚,平稳持续增长时间较长,终极积累量最大,但氮素积累对产量的贡献没有优势。6)粳稻中杂交粳稻69优8号相比其他粳稻品种,氮素积累量大且产量高,也具有氮素转运和利用的高效性。【结论】机插稻植株氮素积累转运特性受不同基因型的显著影响。本研究采用植株含氮量、终极氮素积累量、百千克籽粒吸氮量等反映机插稻氮素吸收转运特性的指标进行比较发现,在育插秧机械化条件下,中籼中熟杂交稻相比中籼迟熟杂交稻和粳稻氮素具有积累转运和利用高效性,其中F优498在氮素积累、分配并促进产量形成方面具有遗传上的优势。中籼迟熟杂交稻虽具有氮素积累量潜力,但氮素积累对水稻产量的贡献相对较低。机插粳稻氮素积累较低,但相比其他粳稻品种机插杂交粳稻69优8号具有氮素积累量大且产量高的潜力,较适合机插。

Differences in N accumulation and translocation in the machine-transplanted rice genotypes

【Objectives】 The experimental objective is to investigate the differences in N uptake and utilization in the machine-transplanted rice genotypes and explore an effective pathway improving uptake and utilization of N in the machine-transplanted rice genotypes.【Methods】 A field experiment was designed in randomized blocks to determine the N content, yields, the characteristics of N accumulation and dry matter weight, distribution and translocation of N in the different machine-transplanted rice genotypes at the growth stages of three medium-maturing varieties, three late-maturing varieties and four japonica rice cultivars, and explain the reasons causing the differences in the characteristics mentioned above.【Results】 1) The accumulation dynamics of N in the machine-transplanted rice was exhibited by a logistic curve. 2) N content in the machine-transplanted rice decreased through the growth period. The content of N in japonica rice cultivars was higher than in indica hybrid rice cultivars during jointing-heading, then that was gradually decreased and became lower than in indica hybrid rice cultivars at maturity. The content of N in medium-maturing indica hybrid rice cultivars reached the highest value at maturity stage. 3) The ultimate N uptake in the japonica rice cultivars was 23.0% lower than in medium-maturing indica hybrid rice cultivars, and 33.1% lower than in late-maturing indica hybrid rice cultivars. 4) Medium-maturing indica hybrid rice cultivars exhibited the highest N accumulation during heading-maturity, and a highly N distribution ratio in the panicle, highly apparent N translocation rate in the leaf and stem-shead with a higher N grain production efficiency and N translocation efficiency, indicating that the accumulation and translocation efficiency of N in the medium-maturing indica hybrid rice cultivars were significantly higher than those in the late-maturing indica hybrid rice cultivars and japonica rice cultivars under the planting mechanization. Fyou498 from medium-maturing indica hybrid rice showed much higher N uptake than the others, and had an advantage of rapid N accumulation at the early growth stage and reasonable N distribution at the late growth stage. 5) Late-maturing indica hybrid rice cultivars demonstrated the biggest enhancement rate in N accumulation from 84 to 91 d, and a steady N accumulation during the whole growth period, and the highest N uptake, but which was not beneficial to yield formation. 6) Cultivar 69you8 has higher N uptakes and yield than the other japonica rice cultivars, and its N accumulation and translocation efficiency was significantly higher under the planting mechanization.【Conclusions】 Different genotypes are significantly different in the characteristics of N accumulation and translocation under machine-transplanting condition. The accumulation and translocation efficiency of N in the medium-maturing indica hybrid rice cultivars is significantly higher than those in the late-maturing indica hybrid rice cultivars and japonica rice cultivars. Fyou498, a medium-maturing indica hybrid rice cultivar, demonstrates genetic advantages in the N accumulation, distribution and yield formation. Late-maturing indica hybrid rice cultivars have potential in high N accumulation, which, however, does not show good to yield formation. N accumulation in the japonica rice cultivars is relatively low. Among the japonica rice cultivars, 69you8 has significantly higher N accumulation and yield under the planting mechanization, showing better suitability for planting mechanization.