双季早稻氮素亏缺补偿效应的形成及其生理机制初探

为探明双季早稻氮素亏缺补偿效应的形成及其生理机制,采用桶栽方式,以超级杂交早稻品种淦鑫203为试验材料,于氮素亏缺敏感期分蘖期,设置5个氮肥处理:T0(各生育阶段均不施用氮肥,即空白对照)、T1(各生育阶段氮肥按常量分配)、T2(分蘖期氮肥亏缺后幼穗分化期不恢复供氮)、T3(分蘖期氮肥亏缺后幼穗分化期常量恢复供氮)和T4(分蘖期氮肥亏缺后幼穗分化期倍量补偿供氮),比较各氮肥处理稻株产量及其构成因素、单株分蘖数、成穗率和净光合速率、SPAD值、氮代谢酶(硝酸还原酶NR和谷氨酰胺合成酶GS)活性、内源激素含量、根系伤流量等有关生理指标的差异性。结果表明,T4单株产量与T1十分接近,补偿指数CI=0.99,无显著差异,呈现出等量补偿效应。与T1相比,T4叶片净光合速率、SPAD值、NR和GS活性均能维持在较高水平,而且随着生育推进,至补偿后期,T4该4项生理指标仍维持在较高水平,表现出较为明显的氮素亏缺补偿效应。至补偿后期,氮素补偿处理的T4和T3稻株叶片脱落酸(ABA)含量显著低于T0、T1和T2,以T4最低,生长促进类激素之和(GA3+IAA+ZR)与生长抑制类激素(ABA)比值则显著高于T0、T1和T2。氮素亏缺补偿后第10天根系伤流量以T0最低,T4、T3均高于T1,且T4与T1间差异达显著水平。至补偿后期,T4单株分蘖数及成穗率高于T1、T3。本研究结果进一步明确了双季超级杂交早稻分蘖期氮素亏缺补偿效应的形成,有助于诠释水稻氮素亏缺补偿效应形成的生理机制,为水稻氮肥施用不当时进行追补及双季早稻高产稳产栽培提供了科学依据。

Primary Research on the Formation and Its Physiological Mechanism of Nitrogen Deficiency Compensatory Effects in Double-season Early Rice

In order to investigate the formation and physiological mechanism of nitrogen deficiency compensatory effects in double-season hybrid early rice,super hybrid early rice variety Ganxin 203 was selected as the material and planted by pot cultivation.At tillering stage of nitrogen deficiency sensitive stage,and five treatments was designed with T0 (Nitrogen fertilizer was no applied in all stages of growth,blank control),T1 (Nitrogen at different stages of growth by constant distribution),T2 (After nitrogen deficiency at tillering stage,no recovery at young panicle differentiation stage),T3 (After nitrogen deficiency at tillering stage,normal application at young panicle differentiation stage),T4 (After nitrogen deficiency at tillering stage,times compensatory application at young panicle differentiation stage).In addition,the physiological indexes of the rice yield and its components,tiller numbers per plant,panicle formation rate,and net photosynthetic rate,SPAD value,nitrogen metabolism enzyme (NR and GS) activity,endogenous hormones,root bleeding sap were compared.The results showed that the yield per plant showed the equivalent compensatory effects,wherein the yield per plant was very close to T4 and T1 (CI =0.99),and no significant difference was observed between the two treatments.Compared with T1,the leaf net photosynthetic rate,SPAD value,NR and GS activity of T4 could be maintained at a higher level.And in the late compensatory growth stage,the four physiological indexes of T4 were still higher.As shown that it had a more significant deficiency and compensatory effects.In the late compensatory growth stage,leaf ABA content in rice plants was the lowest under T4 treatment,and the abscisic acid (ABA) contents for T4 and T3 were significantly lower than those for T0,T1 and T2.The ratios of growth promoted hormones (GA3 + IAA + ZR) and growth inhibited hormones (ABA) in T3 and T4 were significantly higher than those in T0,T1 and T2.After 10 d for nitrogen deficiency compensation,root bleeding sap of T0 was the lowest,while the root bleeding sap in T3 and T4,was higher than that in T1,and the T4 and T1 reached significant difference.In the late compensatory growth stage,the tiller numbers per plant and panicle formation rate of T4 were higher than those of T1 and T3.The results of this study further defined the formation of the nitrogen deficiency compensatory effects for the double-season super hybrid early rice during tillering stage,it also could be helpful to explain the physiological mechanism for the formation of the rice nitrogen deficiency compensatory effects,and provide a scientific basis for rice improper application of nitrogen fertilizer then additional supplemental nitrogen fertilizer and the high and stable yield cultivation in double-season early rice.