Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8875639 | Journal of Integrative Agriculture | 2018 | 10 Pages |
Abstract
High nitrate (NO3â) in vegetables, especially in leaf vegetables poses threaten to human health. Selenium (Se) is an important element for maintaining human health, and exogenous Se application during vegetable and crop production is an effective way to prevent Se deficiency in human bodies. Exogenous Se shows positive function on plant growth and nutrition uptake under abiotic and/or biotic stresses. However, the influence of exogenous Se on NO3â accumulation in hydroponic vegetables is still not clear. In the present study, hydroponic lettuce plants were subjected to six different concentrations (0, 0.1, 0.5, 5, 10 and 50 µmol Lâ1) of Se as Na2SeO3. The effects of Se on NO3â content, plant growth, and photosynthetic capacity of lettuce (Lactuca sativa L.) were investigated. The results showed that exogenous Se positively decreased NO3â content and this effect was concentration-dependent. The lowest NO3â content was obtained under 0.5 µmol Lâ1 Se treatment. The application of Se enhanced photosynthetic capacity by increasing the photosynthesis rate (Pn), stomatal conductance (Cs) and the transpiration efficiency (Tr) of lettuce. The transportation and assimilation of NO3â and activities of nitrogen metabolism enzymes in lettuce were also analysed. The NO3â efflux in the lettuce roots was markedly increased, but the efflux of NO3â from the root to the shoot was decreased after treated with exogenous Se. Moreover, Se application stimulated NO3â assimilation by enhancing nitrate reductase (NR), nitrite reductase (NiR), glutamine synthetase (GS) and glutamate synthase enzyme (GOGAT) activities. These results provide direct evidence that exogenous Se shows positive function on decreasing NO3â accumulation via regulating the transport and enhancing activities of nitrogen metabolism enzyme in lettuce. We suggested that 0.5 µmol Lâ1 Se can be used to reduce NO3â content and increase hydroponic lettuce yield.
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Authors
Bo LEI, Zhong-hua BIAN, Qi-chang YANG, Jun WANG, Rui-feng CHENG, Kun LI, Wen-ke LIU, Yi ZHANG, Hui FANG, Yun-xin TONG,