Journal of Integrative Agriculture ›› 2020, Vol. 19 ›› Issue (1): 133-144.DOI: 10.1016/S2095-3119(19)62775-9

所属专题: 园艺-栽培生理/资源品质合辑Horticulture — Physiology · Biochemistry · Cultivation

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  • 收稿日期:2019-01-23 出版日期:2020-01-01 发布日期:2019-12-23

Selenium distribution and nitrate metabolism in hydroponic lettuce (Lactuca sativa L.): Effects of selenium forms and light spectra

BIAN Zhong-hua1, 2*, LEI Bo1*, CHENG Rui-feng1, WANG Yu2, LI Tao1, YANG Qi-chang1   
 
  

  1. 1 Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing 100081, P.R.China
    2 School of Animal, Rural and Environmental Sciences, Nottingham Trent University, Brackenhurst Campus, NG25 0QF, UK
  • Received:2019-01-23 Online:2020-01-01 Published:2019-12-23
  • Contact: Correspondence BIAN Zhong-hua, Tel: +44-0-1158485284, E-mail: zhonghua.bian@ntu.ac.uk; YANG Qi-chang, Tel: +86-10-82105983, Fax: +86-10-82106021, E-mail: yangqichang@caas.cn
  • About author:* These authors contributed equally to this study.
  • Supported by:
    This work was financially supported by the Central Public Interest Science Institute Basal Research Fund (Y2019xk21-01), the Nottingham Trent University Q&R Fund, UK (01ARE RA 926) and the Key Projects of Ningxia Key R&D Program Fund, China (2018BBF02012).

Abstract:

A deficiency in selenium (Se) in the human diet is a worldwide problem.  The intake of Se-rich vegetables can be a safe way to combat Se deficiency for humans.  However, most leafy vegetables can accumulate a high content of nitrates, which poses a potential threat to human health.  Light is an important environmental factor that regulates the uptake and distribution of mineral elements and nitrogen metabolism in plants.  However, the effects of Se forms and light conditions, especially light spectra, on the uptake and translocation of Se and on nitrate reduction are poorly understood.  In this study, lettuce (Lactuca sativa L.) was treated with exogenous Se applied as selenate (10 mmol L–1) and selenite (0.5 mmol L–1) and grown under five different light spectra: fluorescent light (FL), monochromatic red LED light (R), monochromatic blue LED light (B), and mixed red and blue LED light with a red to blue light ratio at 4 (R/B=4), 8 (R/B=8), and 12 (R/B=12), respectively.  The effects of light spectra and Se forms on plant growth, photosynthetic performance, Se accumulation and nitrate reduction were investigated.  The results showed that the light spectra and Se forms had significant interactions for plant growth, foliar Se accumulation and nitrate reduction.  The Se concentration and nitrate content in the leaves were negatively correlated with the percentage of red light from the light sources.  Compared to Se applied as selenite, exogenous Se applied as selenate was more effective in reducing nitrate via promoting nitrate reductase and glutamate synthase activities.  The lowest nitrate content and highest plant biomass were observed under R/B=8 for both the selenate and selenite treatments.  The significant effect of the light spectra on the root concentration factor and translocation factor of Se resulted in marked variations in the Se concentrations in the roots and leaves.  Compared with FL, red and blue LED light led to significant decreases in the foliar Se concentration.  The results from this study suggest that the light spectra can contribute to Se distribution and accumulation to produce vegetables with better food quality. 

Key words: selenium ,  light spectra ,  nitrates ,  nitrogen metabolism enzymes ,  LEDs ,  Lactuca sativa L.