外源硒对川党参生长的影响及其可能作用机制

Roles and underlying mechanisms of foliar selenium application in regulating growth of Codonopsis tangshen

为探索外源喷施硒肥对川党参生长和营养品质的影响及其可能作用机制,采用大田试验,设置0、25、50、100、200 g∙hm^(-2)和400 g∙hm^(-2)硒肥(以硒元素计)六个处理,观察不同硒肥处理下川党参根茎形态、产量、品质、硒形态和部分根际土壤养分的变化。结果表明,在一定浓度范围内,施用外源硒可增加川党参茎粗、产量、多糖和炔苷含量,其中200 g∙hm^(-2)硒肥处理效果最佳,与对照处理相比差异显著。川党参中的硒主要以有机硒形态存在,有机硒占比超过70%,且有机硒比例随着喷硒浓度的升高呈现先增大后减小的变化趋势,并在硒肥喷施200 g∙hm^(-2)时达到最大,为83.6%。外源喷施25~400 g∙hm^(-2)硒肥对川党参生长总体表现为促进作用,但促进效果随着喷施硒肥浓度的增加呈先增强后减弱的趋势。不同硒肥处理下川党参根际土壤养分存在差异,其中100 g∙hm^(-2)和200 g∙hm^(-2)硒肥处理显著增加了川党参根际土壤碱解氮和速效钾含量。相关性分析和冗余分析表明,改变根际土壤养分含量可能是外源硒影响川党参生长的重要因素之一。综上表明,川党参是硒生物强化的良好材料,在川党参蕾期和花期喷施适量硒肥可提高其产量及多糖、炔苷和硒含量,从而达到生产富硒川党参和提产增质的目的,且以喷施100~200 g∙hm^(-2)硒肥效果最佳。

To explore the effects of foliar selenium(Se)application on the growth and nutritional quality of Codonopsis tangshen 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 C.tangshen.Compared with the control,application of appropriate foliar Se increased root diameter,crop yield,and polysaccharide and lobetyolin content of C.tangshen.Differences between Se treatments and control were statistically significant at the concentration of 200 g·hm^(-2)Se.Selenium in C.tangshen 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 C.tangshen 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 C.tangshen,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 C.tangshen.In conclusion,C.tangshen 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 C.tangshen,thereby promoting the development of Se-enriched C.tangshen products.