Silicon accumulation and distribution in rice as affected by nitrogen levels and genotype differences

Field experiment was conducted in order to investigate the response of silicon accumulation and distribution of 15 rice cultivars (conventional Japonica) to different N levels (0 kg/ha, 150 kg/ha, 225 kg/ha, 300 kg/ha as urea) and genotype variations. Results indicated that the content of silicon in rice organs and plant increased with N rate at three growth stages including elongation, heading and maturity. The percentage of silicon accumulation increased during the periods from transplanting to elongation and from heading to maturity, but decreased from elongation to heading. The proportion of silicon distributed in culm and sheath decreased with N rate, while the proportion in leaf and panicle increased with N rate. The concentration of silicon in rice organs and plant all declined continuously with N rate, except that silicon concentration in panicle increased appreciably at the N level of 300 kg/ha. At each level of N, the characteristics of silicon accumulation and distribution differed significantly with rice genotypes. At the same time, the responses of silicon accumulation and distribution of rice genotypes to N also varied significantly. Among 15 rice cultivars, the silicon accumulation efficiency of Wuyujing 7, Huajing 3,Wuxiangjing 9,Xiangjing 20-18,Wuyujing 3,Wangjing 4003, Zaofeng 9and Huajing 2 increased with or not significantly affected by N levels, having better genetic potential to enhance the resistance to multiple stresses with the increasing application of N in rice production.