种植密度对两种穗型小麦品种分蘖期茎蘖生理特性的影响

Effects of Plant Density on Physiological Characteristics of Different Stems during Tillering Stage in Two Spike-types Winter Wheat Cultivars

选用分蘖成穗率不同的2种穗型冬小麦品种,通过3个密度水平大田试验研究了分蘖期主茎和不同蘖位分蘖间的干物质积累与光合特性的差异,以探讨2种穗型品种分蘖成穗的生理机制.结果显示:(1)在冬小麦分蘖期间,分蘖成穗率低的大穗型品种兰考矮早八高位分蘖干物质积累速率较慢,分蘖与主茎的差距较大;而分蘖成穗率高的多穗型品种豫麦49-198分蘖与主茎的干物质积累速率差距较小.(2)2品种分蘖与主茎干物重比值(蘖/茎)均随着种植密度增加而降低,成穗分蘖的蘖/茎值拔节期均大于0.5,而同期未成穗分蘖均低于0.5.(3)在分蘖期间,兰考矮早八分蘖的净光合速率随生育进程增长比主茎缓慢,且随密度增加分蘖与主茎的差距进一步加大;豫麦49-198分蘖与主茎的光合速率差异较小,且种植密度对其影响也较小.(4)拔节中前期种植密度对2品种的荧光参数影响较小,拔节后期2品种分蘖的初始荧光(F0)均显著大于主茎,而PSⅡ最大光化学效率(Fv/Fm)却显著低于主茎;随种植密度增加,2品种主茎与分蘖的F0和Fv/Fm差异增大,且这种趋势随蘖位上升表现得更加明显.研究表明,大穗型品种兰考矮早八拔节期主茎与分蘖间干物质积累和光合性能的差异过大是其分蘖成穗率低的主要原因.

Under field conditions,two wheat cultivars with different ratio of spikes to tillers were used to study difference of dry matter accumulation and photosynthesis capacity between different tillers and main stems during tillering stage with different planting density.The results indicated that dry matter accumulations in later occurring tillers was lower than that in main stem,with large difference between tillers and main stem in Lankaoaizao 8 (L-8),small in Yumai 49-198 (Y-49).The ratio of tiller to main ...