种植密度对北疆复播大豆光合特性及产量的影响

Effects of Planting Density on Photosynthetic Characteristics and Yield of Summer Soybean in North Xinjiang

以大豆品种‘黑河43’为材料,于2012和2013年连续2年进行5种不同种植密度——37.5（A）、45.0（B）、52.5（C）、60.0（D）和67.5万株·hm-2（E）的田间复播试验,研究滴灌条件下密度对大豆功能叶叶绿素值（SPAD）、叶面积指数（LAI）、比叶面积（SLA）、大豆光合特性及产量构成因素的影响。结果显示：（1）密度对复播大豆苗期叶片SPAD值影响较小,苗期之后处理间差异显著,且整个生育期SPAD值均随着密度的增加而增大。（2）LAI在2年试验中均随着密度的增加而增大,均在鼓粒期左右达到峰值,处理E在2012年和2013年的最大值分别为6.24和5.56,较同期最低的处理A分别显著提高18.41%和36.17%;SLA随着密度的增加而增大,且在生长发育前期和后期处理间差异明显,中期差异相对较小。（3）叶片的净光合速率（Pn）、蒸腾速率（Tr）及气孔导度（Gs）均随着密度的增加而先增后降,且均以C处理最高,Pn、Gs在结荚期达到极值,而Tr在开花期最大;胞间CO2浓度（Ci）随着密度的增加呈现出先降后增的趋势,2012年和2013年均以C处理最低,分别为185.70和179.61μmol·mol-1。（4）各处理2年的籽粒产量均以中等密度的C处理达最高,2012年和2013年分别为3 205.0和3 142.53kg·hm-2,并分别比同年的其余处理显著高出1.42%~14.26%和1.08%~27.65%。研究表明,适宜密度的复播大豆不仅有较高的叶绿素含量,有利于群体对光能的利用,同时具有适宜的叶面积指数而不致植株郁闭,有效保证了群体内部与外界的气体交换,提高了光合速率和籽粒产量。

The field trail was conducted by setting five different planting densities 37.5×104（Treatment A,TA）,45.0×104（Treatment B,TB）,52.5×104（Treatment C,TC）,60.0×104（Treatment D,TD）and 67.5×104（Treatment E,TE）plants·hm-2,under drip irrigation by using of randomized block experimental design in 2012 and 2013summer soybean（‘Heihe 43＇）growing seasons,and the leaf SPAD,leaf area index（LAI）,specific leaf area（SLA）,photosynthetic characteristics and yield components of summer soybean were observed.The result showed that：（1）The leaf SPAD value of summer soybean was less affected by density in seedling stage,but had significant differences among different treatments after seedling stage andincreased with higher density in the whole growth period of summer soybean.（2）The LAI was also improved along with higher density in the two trials,and reached the highest in the seed filling period,and the maximum value of 2012 and 2013in TE were 6.24 and 5.56,which was Significantly higher 18.41% and36.17%than that of the lowest treatment TA at the same period.SLA increased with higher density,too,and had significant differences in the early and late growth stages while the difference was relatively small in middle growth stage.（3）The net photosynthetic rate（Pn）,transpiration rate（Tr）and stomatal conductance（Gs）were increased firstly then decreased with density increase.Pnand Gsreached maximum in the pod-filling period,but Trreached maximum in the flowering period;intercellular CO2concentration（Ci）was first decreased and then increased with density increase,TC was the lowest both in 2012 and 2013,185.70μmol· mol-1 and 179.61 μmol· mol-1,respectively.（4）Treatment C obtained the highest yield of3 205.04kg·hm-2（2012）and 3 142.53kg·hm-2（2013）,which was higher 1.42%-14.26%and 1.08%-27.65%in 2012 and 2013,respectively.Therefore,the summer soybean with optimum density was beneficial to light utilization for the high chlorophyll content,and the optimum LAI without plant canopy closure of suitable density ensured the gas exchange between internal and external,which improved the photosynthetic rate and yield.