棉花不同品种钾吸收效率差异的根系形态学和生理学机理

Mechanisms Underlying the Effects of Morphological and Physiological Characteristics of Cotton Varieties on Differential Potassium Uptake Efficiencies

用6个棉花品种作为试验材料,通过水培试验比较其对钾的吸收能力,研究其根系形态学、生理学特征和K+吸收动力学参数。结果表明,低钾胁迫下,钾高效品种中棉所64的根干物质质量、根体积、根活跃吸收面积、根活跃比表面积最大,根系活力最强;钾高效品种中棉所35的根干物质质量较大、根长而细,根总吸收面积最大,根总比表面积都最大,根系活力也较强,且K+最大吸收速率Imax最大,最小临界浓度Cmin较小,耐低钾能力强。而钾低效品种中棉所50和中植棉2号的根系形态学等指标都较差,根系活力较弱,且Imax也较小。该研究不仅有助于阐明棉花耐低钾胁迫的机理,而且能评价不同品种对低钾的适应能力。

Hydroponics were used to explore the capacity of different cotton varieties to absorb potassium. Six cotton varieties were used to study the effect of different morphological and physiological characteristics on K uptake efficiency and K＋absorption kinetics parameters. The results showed that under low potassium stress, varieties such as CCRI 64, which had high K uptake efficiency, had the largest root dry weight, root volume, active uptake area, active specific surface area, and the strongest root vigor. The high K uptake efficiency variety CCRI 35 also had larger root dry weight, long and fine roots, the largest total root absorption area and total specific surface area, stronger root vigor, the highest K＋maximum absorption rate（Imax）, and lower critical concentration（ Cmin）. CCRI 35 might, therefore, be tolerant of low K stress. Conversely, the K inefficient varieties Zhongzhimian No.2 and CCRI 50 had poor root morphology indicators, weaker root vigor, and smaller K＋maximum absorption rate. The research will not only help to clarify the reasons for resisting low potassium stress among cotton varieties but will also evaluate the adaptability of cotton varieties to low K.