Abstract:

【Objective】 The aim of this research is to investigate the effects of carboxin on seed germination and morphogenesis of cotton seedlings under low temperature and water stress.【Methods】 In this study, the impact of carboxin on seed germination, as well as the morphology, physiological, and biochemical characteristics of cotton seedlings were analyzed.The experiment utilized an artificial climate chamber and controlled the water-holding capacity of potted sandy soil to simulate field conditions of low temperature and water availability.【Results】 The findings revealed that under low temperature stress, the germination rate of cotton seeds was reduced by 21.95%.However, when treated with carboxin, the germination rate increased by 14.06% compared with the low temperature stress alone.Similarly, drought stress caused a 29.41% decrease in seed germination compared with normal watering conditions, whereas carboxin treatment reduced this decrease to 11.67%.Furthermore, low temperature stress significantly reduced the plant height and root length of cotton seedlings, as well as biomass accumulation in the shoots.The stress also led to increased malondialdehyde content and relative permeability of the cell membrane.However, applying carboxin treatment resulted in a reduction of 14.71% and 24.14% in malondialdehyde content and relative permeability, respectively, under low temperature and water stress conditions.Regarding biochemical characteristics, soluble sugar was found to be the main substance under water stress, while soluble protein was predominant under low temperature stress.The highest contents of both soluble sugar and soluble protein were observed in the cotton seedlings coated with carboxin under low temperature and water stress, with increases of 15.56% and 20.14%, respectively.Additionally, under low temperature and water stress conditions, cotton seedlings coated with carboxin exhibited the highest antioxidant enzyme activity and higher expression of antioxidant enzyme-related genes.【Conclusion】 Cotton seed germination and growth are negatively affected by low temperature and water stress, leading to oxidative damage in the leaves.In response to this oxidative stress, cotton seedlings activate mechanisms to scavenge reactive oxygen species and mitigate the damage.The application of carboxin shows promising results in enhancing the resistance of cotton seedlings to low temperature and drought stress.This is achieved by altering the levels of osmotic regulating substances, boosting the activity of antioxidant enzymes, and inhibiting membrane peroxidation.These findings suggest that carboxin has offered a new approach for cotton seedlings to mitigate the impact of environmental disasters and reduce losses.

Key words: carboxin; temperature; water holding capacity; seed germination; physiological indicators

摘要：

【目的】 研究低温与水分胁迫条件下萎锈灵对棉花种子发芽和幼苗形态建成的影响。【方法】 以萎锈灵包衣棉种为材料,利用人工气候箱结合盆栽沙土持水量控制模拟田间低温和水分环境,分析萎锈灵对棉花种子萌发指标、幼苗形态指标和生理生化特性的影响。【结果】 与常温条件相比,低温胁迫处理降低棉花种子的发芽率,降低21.95%;与低温胁迫相比,萎锈灵处理增加棉花种子的发芽率,增加14.06%;与正常水分条件相比,干旱胁迫处理降低棉花种子发芽率,降低29.41%;与干旱胁迫相比,萎锈灵处理增加棉花种子的发芽率,增加11.67%。低温使棉苗的株高、根长显著减小,棉苗地上部的生物量积累减少。在低温水分共同处理下,未包衣处理的丙二醛含量和细胞膜相对透性增大,而萎锈灵包衣棉苗最高分别降低14.71%和24.14%。水分胁迫下渗透调节物质以可溶性糖为主,低温下以可溶性蛋白为主,萎锈灵包衣棉苗低温水分共同处理下两者含量均最高,分别为15.56%和20.14%。低温水分胁迫条件下,萎锈灵包衣棉苗抗氧化酶活性均最大,抗氧化酶相关基因的表达也更高。【结论】 低温和水分胁迫抑制了棉花萌发和生长,导致叶片的氧化伤害。棉苗启动了活性氧清除机制来抵抗氧化损伤。萎锈灵能够通过改变渗透调节物质含量,增强抗氧化酶活性,抑制膜质过氧化,从而增强棉苗的抗低温和干旱迫能力。

关键词: 萎锈灵, 温度, 持水量, 种子萌发, 生理指标