高密度直播油菜不同类型叶片功能探究

Exploring the functions of different leaf types of directly-sown rapeseed under high density

合理密植是确保油菜产量和效益的核心,但过度密植则加重倒伏,难以实现密植再高产。叶片是油菜干物质累积的重要光合器官,但高密度条件下,不同类型叶片对油菜产量及抗倒性的影响尚不明确。本试验以中双11号为材料,设置2个种植密度(D3:4.5×10^(5)株hm^(-2)、D5:7.5×10^(5)株hm^(-2))、4个剪叶处理(CK:不剪叶、LP:剪去一半长柄叶、SP:剪去一半短柄叶、SL:剪去一半无柄叶),探究油菜3种不同类型的叶片对高密度直播油菜产量及抗倒性的影响,为协调高密度油菜源库关系、高产和倒伏矛盾提供理论依据。结果表明:同一密度下,油菜3种不同类型叶片占比均为短柄叶>长柄叶>无柄叶,当密度由D3增加至D5,短柄叶减少约2片,占比由50.6%下降至46.7%。2个密度下,剪叶均降低单株角果数,导致单株产量和实收产量的降低,且以SP处理对产量的影响最大。随着密度增加,SP处理下,单株产量下降幅度由19.61%增加至37.67%,实收产量下降幅度由13.65%增加至22.03%。不同剪叶处理,倒伏指数均增加,且SP处理显著增加了上部和下部的倒伏指数,与其他处理相比抗倒性最弱。此外,单株根系表面积、体积随着密度增加而下降,LP、SP处理下根系表面积和体积均显著下降,以LP处理影响最大。基于相关性分析结果,在D3密度下,剪去短柄叶减少了单株角果数,D5密度下,剪去短柄叶减少了单株角果数和每角果粒数,使产量显著下降、抗倒性下降;剪去长柄叶导致根系表面积、体积显著下降,不利于产量形成。

Optimal planting density is a core technology for ensuring rapeseed yield and production efficiency.However,excessive planting density can worsen lodging of rapeseed and make it challenging to achieve high yields.Leaves play a vital role in photosynthesis and dry matter accumulation in rapeseed,but the effects of different leaf types on yield and lodging resistance under high-density conditions remains unclear.In this study,we selected Zhongshuang 11 and implemented two planting densities(D3:4.5×10^(5)plants hm^(-2),D5:7.5×10^(5)plants hm^(-2))and four-leaf pruning treatments(CK:no leaf pruning,LP:pruning half of the long-petiole leaves,SP:pruning half of the short-petiole leaves,SL:pruning half of the sessile leaves).We aimed to investigate the effects of these three leaf types on the yield and lodging resistance of directly-sown rapeseed under high density,providing a theoretical basis for managing the source-sink relationship,high-density rapeseed cultivation,and the lodging challenge.The results showed that,at the same density,the proportions of short-petiole leaf>long-petiole leaf>sessile leaf.When the density increased from D3 to D5,about 2 short-petiole leaves were reduced,resulted in a decrease in proportion from 50.6%to 46.7%.Leaf pruning at both densities lead to a reduction in siliques per plant,consequently decreasing the yield per plant and actual yield.Among the pruning treatments,SP had the greatest impact on yield.As density increased,the effect of SP on yield per plant increased from 19.61%to 37.67%,and the effect on actual yield increased from 13.65%to 22.03%.The lodging index increased under different leaf pruning treatments,with SP treatment significantly increasing the lodging index in both the upper and lower parts of the plant,indicating weaker lodging resistance.In addition,the root surface area and volume per plant decreased with increasing density,particularly under LP and SP treatments.Correlation analysis revealed that,under D3 density,pruning short-petiole leaves reduced the number of siliques per plant.Under D5 density,pruning short-petiole leaves and long-petiole leaves resulted in reduced siliques per plant and seed per silique,significantly decreasing both yield and lodging resistance.Pruning long-petiole leaves led to a significant decrease in root surface area and volume,which was unfavorable for yield formation.