土壤水分空间胁迫对棉花根系构型的影响

Effect of Spatial Soil Moisture Stress on Cotton Root Architecture

【目的】探究土壤水分空间胁迫对棉花根系生长所造成的影响,分析比较棉花根系构型的相应变化。【方法】为形成土壤水分空间胁迫,棉花株距设为30 cm,且从测坑的一侧灌水。通过对棉花根系的挖掘,分析远离灌水点棉株主根分叉现象。【结果】靠近灌水点的棉株A根区土壤水分空间分布较均匀,根系构型基本呈现"伞状"对称分布,主、侧根直径差为5~6 mm,主、侧根平均夹角在70°~80°,并随生育阶段的推进而减小。远离灌水点的棉株C受到土壤水分空间胁迫,根系构型分布不对称,偏向土壤水分高的地方生长,48.15%的侧根变粗,表现为主根分叉现象;其中分叉根之间的直径相差1~4 mm,分叉根沿垂直方向的夹角在20°~37°,并随生育阶段的推进而增大。【结论】研究结果对从棉花生理生态角度认识灌溉土壤有效湿润区的设计理论有帮助。

[Objective]This study aimed to explore the effects of spatial soil moisture stress on cotton root growth,and to analyze the corresponding changes in cotton root architecture.[Method]To produce soil moisture spatial stress,cotton spacing was set at 30 cm.The cotton was all irrigated on one side of the pole(the side sampling point).By excavating the cotton root,analysis of the main root bifurcation,which was cultivated away from the irrigation point,could be undertaken.[Result]The analyses of the cotton A(the nearest plant to the irrigation location)root system showed that soil moisture near the irrigation point was distributed uniformly.The root system architecture of the cotton cultivated near the irrigation point mostly presented a symmetrical"umbrella"pattern;the difference in root diameter between the main and lateral roots was 5–6 mm,and the average angle between them was 70°–80°,which decreased with the increase in cotton growth stage.Soil moisture spatial stress influenced the cotton plant C,which was cultivated away from the irrigation point,such that the root system architecture was asymmetrical.The roots of cotton plant C grew towards the high soil moisture zone;48.15%of the lateral roots became thicker,which acted as a bifurcated main root.The difference in diameter between the bifurcated roots was 1–4 mm,and the average angle of the bifurcated roots along the vertical direction was between 20°–37°,which increased with the increase in cotton growth stage.[Conclusion]The results provide important information on the physiological responses of the cotton root system to the soil moisture environment.