镉胁迫下蓖麻对镉及矿质元素的富集特征

Cadmium and Mineral Nutrients Accumulation in Various Genotypes of Castor under Cadmium Stress

目前中国农田遭受镉污染的情况日益严重。蓖麻（Ricinus communis L.）是一种能源作物,同时对镉有较高的耐性和富集能力,因此利用蓖麻资源为合理利用镉污染农田提供了一种可行的途径。在温室条件下（5~32℃）采用盆栽试验,设定2个镉质量分数梯度（2.396和5.396 mg·kg-1）,研究镉胁迫下30种蓖麻品种茎、叶和果实对镉和矿质元素（铝、钼、铜、钙、锌、硫、磷、镁、锰和铁）吸收和富集特征,以及矿质营养元素与镉富集的相关性。结果表明：镉在不同组织的分布情况为茎〉叶〉果实,铝、钼、硫、锰和铁在不同组织的分布为叶〉果实〉茎,钙和镁在不同组织的分布为叶〉茎〉果实,铜、锌和磷在不同组织的分布为果实〉叶〉茎。在低镉质量分数（2.396 mg·kg-1）处理条件下,茎、叶和果实中镉质量分数变化范围分别为0.600~1.670、0.310~1.970和0.130~0.909 mg·kg-1,平均值分别为1.030、0.831和0.362 mg·kg-1。在高镉质量分数（5.396mg·kg-1）处理条件下,茎、叶和果实中镉质量分数变化范围分别为1.012~4.032、0.698~3.514和0.227~1.525 mg·kg-1,平均值分别为1.964、1.583和0.694 mg·kg-1。蓖麻茎、叶和果实对镉和矿质元素（铝、钼、铜、钙、锌、硫、磷、镁、锰和铁）的富集受蓖麻品种和土壤中镉含量的显著影响。钙、硫、镁、铁的积累与镉的吸收呈显著正相关关系;锌、锰、铜、磷的积累与镉的吸收呈显著负相关关系,而铝、钼的积累与镉的吸收无显著相关关系。因此,合理调控污染土壤中矿质元素的含量可以提高蓖麻对镉污染土壤的修复效率。

Cadmium （Cd） pollution of farmland is an increasing problem in agriculture worldwide. Castor bean （Ricinus communis L.） is a valuable and renewable resource, which can be used as an energy source and for bioremediation of Cd contaminated soil. The absorption and accumulation of Cd and specific mineral elements （Al, Mo, Cu, Ca, Zn, S, P, Mg, Mn and Fe） in the stem, leaf and fruit of 30 castor cultivars with different genotypes under Cd stress （2.396 mg·kg-1 and 5.396 mg·kg-1） were investigated with pot experiments in a greenhouse （5~32 ℃）. The accumulation of Cd in different tissues follows the order：stem〉leaf〉fruit, whereas the accumulation of Al, Mo, S, Mn and Fe follows the order： leaf 〉 fruit 〉 stem. Moreover, the accumulation of Ca and Mg in different tissues follows the order：leaf〉stem〉fruit, whereas the accumulation of Cu, Zn and P follows the order：fruit〉leaf〉stem. Under low-Cd conditions （2.396 mg·kg-1）, the range of Cd contents was 0.600~1.670 mg·kg-1 in the stems, 0.310~1.970 mg·kg-1 in the leaves, and 0.130~0.909 mg·kg-1 in the fruit. The average Cd contents in stems, leaves, and fruit were 1.030, 0.831, and 0.362 mg·kg-1, respectively. Under high-Cd conditions （5.396 mg·kg-1）, the range of Cd contents was 1.012~4.032 mg·kg-1 in the stems, 0.698~3.514 mg·kg-1 in the leaves, and 0.227~1.525 mg·kg-1 in the fruit. The average Cd contents in stems, leaves, and fruit were 1.964, 1.583, and 0.694 mg·kg-1, respectively. The results showed that Cd and mineral element contents in the stem, leaf and fruit of castor were significantly affected by the Cd contents in the soil and cultivars. Significant positive correlations could be found between Cd and Ca, S, Mg as well as Fe. Negative correlations could be detected between Cd and Mn, Cu, Zn as well as P. No correlations were found between Cd and Al as well as Mo. Therefore, the Cd phytoremediation efficiency of castor could be improved by regulating the contents of mineral elements in the contaminated soil.