不同程度镉污染对棉花生长和镉富集特征的影响

【目的】研究不同程度镉污染土壤下棉花生长和镉富集的特征。【方法】采用盆栽模拟方法,添加外源镉,分析棉花种植后土壤pH和镉含量的变化,以及镉胁迫对棉花生长和镉积累量的影响。【结果】棉花根系具有酸化作用,使其根际土壤pH下降,随镉胁迫浓度的增加,酸化受到抑制,土壤有效态镉含量随之显著降低。棉花株高和地上部生物量随镉浓度增加逐渐降低,根系则相反。棉花各器官镉含量、转移系数与积累量随镉浓度的增加显著升高。在不同镉胁迫下,棉花根系镉富集系数均>1。在10 mg/kg镉胁迫下茎、叶和蕾富集系数分别达到0.98、0.33和0.63;镉富集量分别为74.01、39.5和98.623 μg/盆,表现出较强的积累能力。【结论】在镉胁迫下棉花根系生物量增加,地上部生物量降低,随镉浓度的增加,棉花镉积累量增大,在5和10 mg/kg镉胁迫下棉花地上部镉积累量显著高于地下部。

Effects of Different Levels of Cadmium Pollution on Cotton Growth and Cadmium Enrichment

【Objective】 To explore the characteristics of cotton growth and cadmium enrichment under different degrees of cadmium contaminated soil. 【Methods】 The potted plant simulation test method was used to explore the changes of soil pH and cadmium content after cotton planting and the effects of cadmium stress on cotton growth and cadmium accumulation through the addition of cadmium. 【Results】 Cotton roots are acidified, which caused the pH of the rhizosphere soil to decrease. As the concentration of cadmium stress increased, acidification was inhibited, and the available soil cadmium content was significantly reduced. Cotton plant height and aboveground biomass gradually decreased with the increase of cadmium concentration, while the root system was reversed. The cadmium content, transfer coefficient and accumulation of cotton organs increased significantly with the increase of cadmium concentration. Under different cadmium stress, the cadmium enrichment coefficients of cotton roots were all greater than 1. Under 10 mg/kg cadmium stress, the enrichment coefficients of stems, leaves and buds reached 0.98, 0.33, and 0.63 respectively; the cadmium enrichment amounts were 74.01, 39.5, and 98.623 μg/pot respectively, showing strong accumulation capacity. 【Conclusion】 Under cadmium stress, cotton root biomass increases and above-ground biomass decreases. With the increase of cadmium concentration, cotton cadmium accumulation increases. And cotton above-ground cadmium under 5 and 10 mg/kg cadmium stress, the accumulation is significantly higher than that of underground cotton.