Roles and underlying mechanisms of foliar selenium application in regulating growth of <i>Codonopsis tangshen</i>

• Main Authors: ZHOU Wu-xian, LIU Cui-jun, DUAN Yuan-yuan, ZHANG Mei-de, AI Lun-qiang, WEI Hai-ying, ZHANG Ya-juan
• Format: Article
• Language: zho
• Published: Agro-Environmental Protection Institute, Ministry of Agriculture 2021-07-01
• Series: Journal of Agricultural Resources and Environment
• Subjects: selenium; microelement; <i>codonopsis tangshen</i>; spray application; polysaccharide; lobetyolin; selenium speciation; rhizospheric soil nutrient
• Online Access: http://www.aed.org.cn/nyzyyhjxb/html/2021/4/20210409.htm

To explore the effects of foliar selenium(Se) application on the growth and nutritional quality of <i>Codonopsis tangshen</i> and elucidate the mechanisms underlying plant response to supplementation with selenium, a field experiment with six treatments(0, 25, 50, 100, 200 and 400 g·hm^-2 Se in sodium selenite) was conducted to determine the effects of different Se treatments on root morphology, yield, quality, Se speciation and partial rhizospheric soil nutrients of <i>C. tangshen</i>. Compared with the control, application of appropriate foliar Se increased root diameter, crop yield, and polysaccharide and lobetyolin content of <i>C. tangshen</i>. Differences between Se treatments and control were statistically significant at the concentration of 200 g · hm^-2 Se. Selenium in <i>C. tangshen</i> mainly existed in the form of organic Se(>70% of total Se), and the proportion of organic Se initially increased and then decreased with increasing foliar Se. The maximum value of organic Se was 83.6% when the foliar Se level was 200 g·hm^-2. The Se treatments promoted the growth of <i>C. tangshen</i> under Se level of 25~400 g·hm^-2; however, the promotion effects firstly increased and then decreased with the increasing foliar Se level. Significant differences of rhizospheric soil nutrients among different Se treatments were observed:The 100 g · hm^-2 and 200 g · hm^-2 Se treatments significantly increased the rhizospheric soil alkali-hydrolyzed nitrogen and available potassium content of <i>C. tangshen</i>, compared with the control. Pearson analysis and redundancy analysis showed that the change of nutrient content in rhizosphere soil might be an important factor affecting the growth of <i>C. tangshen</i>. In conclusion, <i>C. tangshen</i> was a good candidate for Se supplementation and spraying 100~200 g · hm^-2 Se in the bud and flowering stage could increase the yield, polysaccharide, lobetyolin and Se content of <i>C. tangshen</i>, thereby promoting the development of Se-enriched <i>C. tangshen</i> products.