浔郁平原不同作物的硒富集特征及其影响因素

作物中的硒含量是影响食物链硒水平的关键因素。以浔郁平原土地质量地球化学评价项目中的农作物调查结果和多年定位试验结果为基础,探究不同作物对土壤硒的富集特征及其影响因素。结果表明:浔郁平原的覃塘、港南、桂平市和平南县等4个县(市、区)的水稻富硒率均高于86%。花生、黄豆、玉米和水稻的天然富硒率最高,富硒率依次为100%、100%、100%和89%。水稻根、茎、籽粒的生物富集系数依次下降,分别为0.663、0.130和0.108,水稻籽粒的生物富集系数远高于龙眼、荔枝和甘蔗。根系土与水稻籽粒硒含量的相关系数为0.660,远高于龙眼和荔枝。港南区作物硒与土壤pH相关系数为0.342,在碱性土壤中甘蔗茎的硒含量(0.012 1 mg/kg)最高,在酸性土壤中水稻的硒含量(0.0653mg/kg)最高。本研究中,以种子为可食部分的作物其天然富硒率较高,土壤硒含量和土壤酸碱性对水稻籽粒硒含量影响较大。

Selenium Accumulation Characteristics and Influential Factors of Different Crops in Xunyu Plain

Selenium (Se) content in crop is one key factor affecting Se level in food chains. Based on the results of geochemical survey of soil environmental quality regarding crops and long-term positioning observation in Xunyu plain, Se accumulation characteristics of crops and influential factors were studied. Results showed that more than 86% of the rice were rich in Se in Qingtang, Gangnan, Guiping and Pingnan. In the studied area, the proportions of Se-rich peanut, soybean, corn and rice were 100%, 100%, 100% and 89%, respectively. Se bioconcentration factors of the root, stem, and grain of rice were 0.663, 0.130 and 0.108, respectively. Se bioconcentration factor of rice grain was much higher than those of longan, litchi and sugarcane. The correlation coefficient between Se contents in the rice grain and rice rhizosphere soil was 0.660, higher than those of longan and litchi. The correlation coefficient between Se contents in crops and soil pH was 0.342 in Gangnan. Se content in sugarcane stem (0.012 1 mg/kg) was higher in the alkaline soils than in other crops, whereas in the acid soils Se content in rice grain (0.065 3 mg/kg) was the highest among all the crops. These results indicated that the crops with seeds as edible part are generally rich in Se in the Xunyu plain, and Se content in rice is largely affected by soil Se content and pH.