镉低积累青菜品种筛选及硫对镉胁迫下青菜镉含量和品质影响

Selection for low-Cd-accumulating cultivars of pakchoi(Brassica chinensis L.), effects of sulfur on Cd content, and quality characters under Cd stress

以36个不同基因型青菜品种为材料,采用盆栽试验,根据可食部分生物量和镉(Cd)积累量差异,筛选Cd低积累和Cd高积累青菜品种,利用小区试验,研究外施硫对不同Cd积累型青菜品种可食部分Cd含量和营养品质的影响。结果表明:不同浓度Cd处理下,36个青菜品种可食部分生物量和Cd含量差异显著;紫罗兰(ZLL)和矮脚黄(AJH)2个青菜品种符合Cd低积累品种特征,适宜在Cd中低污染土壤(Cd≤1 mg·kg^(-1))种植;壶瓶长梗白(HPCGB)和抗热605(KR605)2个青菜品种可食部分Cd含量较高,为Cd高积累品种。小区试验结果进一步验证了盆栽筛选出的Cd低积累和Cd高积累品种特性。1 mg·kg^(-1)Cd处理水平下,2个Cd低积累和2个Cd高积累青菜品种可食部分可溶性蛋白、可溶性糖和硝酸盐含量均高于对照;5 mg·kg^(-1)Cd处理水平下,上述4个青菜品种硝酸盐含量超过食品安全国家标准限量(GB 18406.1—2001);外施硫可不同程度降低青菜可食部分Cd含量和硝酸盐含量,提高了可食部分可溶性蛋白、可溶性糖和维生素C含量。在Cd中低污染大田种植紫罗兰(ZLL)和矮脚黄(AJH)青菜品种及外施硫可有效降低可食部分Cd含量和改善蔬菜品质。

In order to reduce the risk of heavy metal pollution, pot culture experiments were performed to screen out low-Cd-accumulating cultivars（LCACs）and high-Cd-accumulating cultivars（HCACs）from among 36 pakchoi cultivars, and plot experiments were conducted to investigate the influence of exogenous sulfur on Cd content and nutritional quality in edible parts under Cd stress. Results of the pot culture experiments revealed that the biomass and Cd concentrations of the edible parts of the plant under the three Cd treatments varied significantly across cultivars. Two cultivars, ZLL and AJH, met all the screening criteria of LCACs, and thus could be categorized as LCACs. In contrast, HPCGB and KR605, which had the highest Cd concentrations in edible parts under Cd1（1 mg·kg^（-1） Cd）and Cd5（5 mg·kg^（-1） Cd）treatments, were selected as HCACs. The plot experiments further confirmed the results of the pot culture experiments and the low Cd accumulating traits of the two LCACs under various Cd treatments. The soluble protein, soluble sugar, and nitrate content in the edible parts of the four selected cultivars was higher than that in the control when exposed to Cd1, and the nitrate content in the edible parts of the four selected cultivars exceeded the National Food Safety Standards in China（GB 18406.1—2001）under the Cd5 treatment. Exogenous sulfur could effectively decrease Cd and nitrate content, whereas it increases the soluble protein, soluble sugar, and vitamin C content in edible parts of pakchoi. In conclusion, cultivating LCACs（ZLL and AJH）with a Cd concentration ≤ 1 mg·kg^（-1） as well as applying sulfur could reduce Cd content in the edible parts of pakchoi and improve vegetable quality.