Abstract: 【Objective】 The purpose of this paper is to reveal the response mechanism of root indexes of different salt-tolerant island cotton seedlings to saline-alkali stress in the hope of providing scientific theoretical basis for breeding and saline-alkali tolerant planting of island cotton in Xinjiang, China. 【Method】 The salt mixture of neutral salt mixed salt (neutral salt) and basic salt mixed salt (alkaline salt) was simulated by mixing 1∶1 with a mixture of NaCl, Na₂SO₄, NaCl and NaHCO₃. When the total salt concentration (Na⁺) was 0, 120, 180, 240 mmol/L., the neutral and alkaline salt stresses on root morphology as well as the relationship between root morphology were analyzed using four island cotton cultivars (salt-sensitive cultivar Xinhai 48,weak salt-resistance cultivar xinhai31, maderate salt-resistance cultivar Xinhai 43 and salt-resistance cultivar Xinhai 35) as materials.【Result】 The results showed that differences existed in the response of root morphology of island cotton (Gossypium hirsutum L.) to neutral and alkaline salts. When the neutral salt concentration was 180 mmol/L, the total length of the roots of different salt-tolerant species of sea-island cotton was not significantly different from that of the control, and Xinhai 31 and Xinhai 35 were 18% and 5.97% higher than those of the control, respectively. Under the treatment of alkaline salt 120 mmol/L and 180 mmol/L, the total root length of Xinhai 35, Xinhai 43 and Xinhai 48 was significantly reduced by 38.24%-46.32%, 64.25%-75.58% and 39.91%-71.47%, respectively. When the neutral salt concentration was between 180 and 240 mmol/L, the root length, root surface area and root volume of different salt-tolerant species of island cotton increased to different extents. When the alkaline salt concentration was between 120 and 180 mmol/L, the root length, root surface area and root volume of different salt-tolerant species of island cotton were reduced to different extents. 【Conclusions 】 Low concentration of neutral and alkaline salt increased fine root length, fine root area and fine root volume of different salt-tolerant varieties of island cotton to varying degrees, but had no significant inhibitory effect on medium and coarse root. The total root length, total surface area and total volume of island cotton were significantly reduced under neutral and alkaline salt stresses, alkaline salt had a greater effect on the total root length. Alkaline salt mainly reduced the total root length by inhibiting the elongation of fine root.

Key words: island cotton; neutral salt; alkaline salt; root morphology; salt tolerance

摘要： 【目的】 研究不同耐盐性海岛棉幼苗根系指标对盐碱胁迫响应的机理,为新疆海岛棉育种和耐盐碱种植提供科学依据。【方法】 以盐敏感品种新海48号、弱耐盐品种新海31号、中等耐盐品种新海43号和耐盐品种新海35号为材料,采用NaCl、Na₂SO₄(物质的量1∶1)和NaCl、NaHCO₃(物质的量1∶1)模拟不同程度的中性盐混合盐(中性盐)和碱性盐混合盐(碱性盐)胁迫,总盐浓度(Na⁺)为0、120、180、240 mmol/L,分析中性盐和碱性盐两种胁迫下海岛棉幼苗根系形态特征及其与植株耐盐性的关系。【结果】 海岛棉根系形态对中性盐和碱性盐的响应存在差异,中性盐浓度为180 mmol/L时,不同耐盐品种海岛棉根系总长度与对照相比均无显著差异,新海31号、新海35号分别比对照高18%和5.97%;在碱性盐120和180 mmol/L处理下,新海35号、新海43号和新海48号的根系总长度较对照分别显著减低38.24%~46.32%、64.25%~75.58%和39.91%~71.47%。当中性盐浓度处于180~240 mmol/L时,不同耐盐品种海岛棉细根根长、表面积和体积在不同程度上有所增加;当碱性盐浓度处于120~180 mmol/L时,不同耐盐品种海岛棉细根根长、表面积和体积在不同程度上有所降低。 【结论】 低浓度中性盐和碱性盐使不同耐盐品种海岛棉细根根长、表面积及体积有不同程度的增加,而对中根及粗根无显著抑制作用。中性盐和碱性盐胁迫均显著降低海岛棉根系总长度、总表面积和总体积,其中碱性盐对根系总长度的影响较大,碱性盐主要通过抑制细根的伸长来降低根系总长度。

关键词: 海岛棉, 中性盐, 碱性盐, 根系形态, 耐盐特性