施锌对棉花不同生育期净同化率的影响

Effect of zinc application on net assimilation rate of different cotton growth stages

应用田间试验研究了锌素施用下棉花净同化率的动态变化规律。研究发现,随着锌素用量的增加,棉花产量先升高后降低,施ZnSO4.7H2O为20 kg/hm^2产量达到最高; 随着棉花生长发育进程,净同化率（NAR）呈现先升高后降低的趋势,蕾期-花期（LH）为最大; 生长前期（苗期-盛花期）,随着锌用量的增加,NAR呈明显上升趋势,而生长中后期（花期-吐絮期）,随着锌素施用量的增加,净同化率明显降低,在生长后期尤其是铃期以后,NAR对锌素反应表现的比较异常,不论锌施用量多少,NAR均低于对照; 在盛花期-铃期,锌素用量和NAR之间不论是直线型、指数型还是二次曲线型关系,都达到显著水平,但以一元二次曲线拟合更好。

Dynamic regulation of cotton net assimilation rate（NAR） was studied under zinc application by field experiment. The results showed that with the increased use of zinc, the yield had a tendency of increasing first and decreasing then; and as the process of and development of cotton, NAR had a tendency of increasing first and decreasing then. In the period of flourishing budding to flourishing flowering, NAR reached the maximum. With the enhancement of zinc dosage, NAR increased at growth prophase and decreased at metaphase to anaphase obviously. After bell period, the response of NAR to exogenous zinc showed very exceptional, and regardless of the amount of zinc fertilized, NAR was always lower than that of control. At the period of full flowering to bell, whether the relationship of NAR and zinc amount is linear, exponential or a quadratic curve-type, they all reached a significant level. Nevertheless, the quadratic curve was fitting better. Thus, by studying the effect of zinc application on net assimilation rate of different cotton growth stages, we may obtain some new ideas of rational fertilization for cotton cultivation.