低钾胁迫下不同钙浓度对烟草钾吸收的影响

为探讨低钾胁迫下钙对烟株生长发育及钾素吸收的影响及其机制，通过室内水培法，以烟草品种K326为试验材料，设置2个钾水平和6个钙浓度，分别测定烟株生理特征、根系钙离子含量和ATPase活性及烟株各部位钾含量。结果表明，不同钾水平对烟株生长发育及钾吸收影响显著，低钾水平下的烟株地上部及根系物质量、烟株生理指标及各部位钾含量均低于常钾水平，低钾胁迫下烟株地上部及根系钾含量分别降低了71.80%~25.63%和88.68%~45.47%。同一钾水平下，随着钙浓度的升高，烟株各部位物质量、烟株生理指标、烟株各部位钾含量呈现先升高后降低的趋势。低钾胁迫下，烟株各部位物质量、叶片和根系可溶性蛋白含量、叶片POD和CAT酶活性及烟株各部位钾含量以钙浓度为5 mmol/L时表现最佳，其中根系钾含量达到7.323 mg/g。低钾胁迫显著影响烟株生长发育及钾吸收，外界适当的Ca²⁺浓度可以促进烟株K⁺吸收，但过高的Ca²⁺浓度则会对烟株K⁺吸收产生抑制，水培条件下钙浓度为5 mmol/L时最利于烟株生长发育及钾吸收。

Effects of Different Calcium Concentrations on Tobacco Potassium Uptake under Low Potassium Conditions

The effect and mechanism of calcium on plant growth and potassium uptake were analyzed under low potassium conditions. Plants of tobacco variety K326 were grown under indoor hydroponic conditions, and two potassium levels and six calcium concentrations were set to determine physiological characteristics of plants, root calcium ion concentration, root ATPase activity and potassium concentration in various parts of the plant. The results showed that:Different potassium levels significantly affected tobacco plants' growth and potassium uptake. Dry and fresh mass of shoots and roots, physiological characteristics and potassium content in various parts of the plants under low potassium conditions were lower than those under normal potassium conditions. Potassium contents in shoots and roots of tobacco plants under low potassium condition were decreased by 71.80%-25.63% and 88.68%-45.47%, respectively. At the same potassium level, dry and fresh mass of shoots and roots, physiological characteristics, and potassium contents in various parts of the plants showed a trend of increasing firstly and then decreasing with the increase of calcium concentration. Under low potassium conditions, dry and fresh mass of each part of the plants, soluble protein content in leaves and roots, POD and CAT activities in leaves, potassium content in every parts of tobacco plants were optimal if provided with 5 mmol/L calcium concentration. Root potassium content reached 7.323 mg/g. Low potassium condition significantly affected tobacco plant growth and potassium uptake. Appropriate Ca²⁺ concentrations can promote K⁺ uptake, but excessive Ca²⁺ can inhibit K⁺ uptake. Calcium concentration of 5 mmol/Lunder hydroponics is the most suitable for tobacco growth, development and potassium uptake.