不同氮肥处理下机插杂交稻的根系动态生长特征研究

【目的】研究不同氮肥用量下机插杂交稻的根系生长特征的变化规律及其与产量关系。【方法】以两个杂交水稻组合全两优1号和全两优681为供试材料,设置N_0(0 kg/hm~2)、N_1(150 kg/hm~2)和N_2(250 kg/hm~2)氮肥处理。利用Minirhizotron分析两个品种移栽后20 d至开花期在0~30 cm土层中的根系分布和动态变化特征。【结果】研究结果表明,氮肥处理对两个杂交稻根数、根长、根体积和根表面积影响显著。N2处理下两个品种的总根数显著多于N1,且全两优1号和全两优681的总根数相比对照N1分别增加了12.3%和17.6%,两个品种的总根量在移栽后65 d达到最大值。随着施氮量的增加,两个杂交稻品种的根数、根长、根体积和根表面积在0~10 cm和10~20cm两个土层深度均有所增加,其中以10~20 cm土层深度的根量增幅最为显著。10~20 cm土层深度的总根长与产量、根数与产量显著相关,且相关系数分别高达0.80和0.87,且全两优681在10~20 cm土层深度为的总根量要显著高于全两优1号。【结论】高氮下总根量增加,但10-20 cm土层中的根系分布对产量影响最大,因此,生产中通过培育和增加深层根系的比例有利于水稻实现高产高效。

Dynamic Growth Characteristics of Roots of Mechanically-transplanted Hybrid Rice Under Different Nitrogen Treatments

【Objective】This experiment is to study the dynamic characteristics of roots grown under different nitrogen levels and their relationship with grain yield in mechanically-transplanted hybrid rice.【Method】Two-line hybrid rice combinations, Quanliangyou 1 and Quanliangyou 681, were grown under different nitrogen treatments, N0(0 kg/hm2), N1(150 kg/hm2) and N2(250 kg/hm2), respectively. The dynamic root morphological traits and distribution(0－30 cm) from 20 days after transplanting(DAT) to flowering were analyzed with minirhizotron technique.【Result】The total number of roots, root length, root volume and root surface area were all significantly affected by nitrogen levels. The total number of roots of the two combinations under N2 treatment was significantly higher than that under N1 treatment. Compared with N1 treatment, the total number of roots of Quanliangyou 1 and Quanliangyou 681 increased by 12.3% and 17.6%, respectively. The total number of roots of the two combinations maximized 65 days after transplanting. With the increasing amount of nitrogen, the number of roots, root length, root volume and root surface area increased in different soil layers, but the layer (10－20 cm) was much more significant compared with others. The correlation coefficients between the total root length (10－20 cm) and grain yield, the number of roots (10－20 cm) and grain yield were 0.80 and 0.87, respectively, reaching the significant level. Both the number of roots and grain yield of Quanliangyou 681 were much higher than those of Quanliangyou 1.【Conclusion】Higher nitrogen level improve the root biomass, while the root distribution in the soil layer(10－20 cm) is closely related to the grain yield. Given this situation, increasing the deep root distribution can make extraordinary contribution to the improvement of the grain yield.