不同耐旱性棉花品种根系生长及水分利用效率对干旱的响应机制

【目的】研究耐旱性不同的棉花品种根系生长及水分利用效率对干旱的响应机制,为棉花抗逆栽培和耐旱性品种选育提供理论依据。【方法】以不耐旱性品种新陆早17号和耐旱型品种新陆早22号为试材,设常规灌溉(CK)、轻度干旱(W₁)和中度干旱(W₂)处理,测定不同处理下棉花产量形成期0~120 cm 土层根长密度、根体积密度、根重密度及水分利用效率。【结果】干旱处理下,0~20 cm土层内,2品种根重密度、根体积密度、根长密度均显著低于CK;80~120 cm土层内,新陆早22号随干旱胁迫程度的增强而增加,新陆早17号则降低。W₁、W₂处理的水分利用效率分别比CK高15.18%、21.91%。品种间,新陆早22号根长密度在40~80 cm土层的分布比例显著高于新陆早17号,80~120 cm土层的分布比例显著低于新陆早17号。新陆早22号耗水量比新陆早17号低6.30%,但水分利用效率比新陆早17号高40.95%,差异显著。新陆早22号在80~120 cm 土层根体积密度与生物学水分利用效率呈显著正相关。【结论】耐旱型棉花品种通过增加深土层根系分布比例延伸其在干旱下汲取水分空间,保证地上部生长,实现有限水分高效吸收与利用。

Response of Root Growth and Water Use Efficiency to Drought in Different Drought Tolerant Cotton Varieties

【Objective】 To clarify the response mechanism of root growth and water use efficiency of cotton varieties with different drought resistance to drought, and provide a theoretical basis for cotton stress-resistant cultivation and drought-tolerant varieties selection. 【Method】 Under soil column cultivation conditions, the not drought-tolerant variety Xinluzao 17 and the drought-tolerant variety Xinluzao 22 were taken as the test materials, with conventional irrigation (CK), mild drought (W₁) and moderate drought (W₂) treatments set to study the effects of drought stress on root length density, root length density distribution ratio, root volume density, root weight density, water consumption and water use efficiency of different drought-tolerant cotton varieties. 【Result】 Under drought treatment, the root weight density, root volume density and root length density of the two varieties in the 0-20 cm soil layer were significantly lower than those of CK; The distribution ratio of Xinluzao 22 root length density in 40-80 cm soil layer was significantly higher than that in Xinluzao 17 soil layer, while the distribution ratio of Xinluzao 17 decreased. Compared with CK, the water use efficiency of W₁ and W₂treatments increased by 15.18% and 21.91%, respectively. Among cultivars, the distribution ratio of root length density of Xinluzao 22 in the 40-80 cm soil layer was significantly higher than that of Xinluzao 17, and the distribution ratio of the 80-120 cm soil layer was significantly lower than that of Xinluzao 17. The water consumption of Xinluzao 22 was 6.30% lower than that of Xinluzao 17, but the water use efficiency was 40.95% higher than that of Xinluzao 17, which was a significant difference. Correlation analysis showed that the root bulk density of Xinluzao 22 in the 80-120 cm soil layer was significantly positively correlated with biological water use efficiency.【Conclusion】 Drought-tolerant cotton varieties extend their water absorption space under drought by increasing the distribution ratio of roots in deep soil layers to ensure the growth of the above ground and achieve efficient absorption and utilization of limited water.