Effects Of Different Rootstock Combinations On Growth And Nutrient Absorption Of Nasturtium Officinale Cuttings

Nasturtium officinale is a cruciferae aquatic vegetable,which has the characteristics of fast growth and easy cutting,and is easy to produce and breed.This experiment uses a potted method,N.officinale was used as the experimental material to study the growth,selenium accumulation and tolerance of soil under different concentrations of selenium.In order to reveal the selenium accumulation rule of N.officinale,to understand its adaptation,accumulation and tolerance to selenium,and to screen out the concentration of soil selenium suitable for its growth.On this basis,N.officinale is used as scion,and five cruciferous plants(Brassica chinensis,Brassica campestris L.,Raphanus sativus L.,Rorippa dubia,Brassica oleracea L.)are the rootstocks,exploring the effects of cuttings on the growth,selenium accumulation and nutrient uptake of N.officinale prior grafting with different rootstocks.The best rootstock was then screened for B.oleracea L..Finally,B.oleracea L.was used as the rootstock to explore the effects of cuttings on the growth,selenium accumulation and nutrient uptake of N.officinale prior grafting with different numbers,which provided a reference for the study of the rootstock-scion interaction and selected suitable grafting numbers.The main findings are as follows:1.N.officinale has a wide tolerance to selenium and strong accumulation ability.It is a secondary selenium-enriched plant.There is a positive linear regression relationship between selenium content and selenium accumulation of N.officinale and exogenous selenium concentration.The concentration of exogenous selenium at 10 mg/kg is most beneficial to the growth of N.officinale.At this concentration,the selenium content in the shoot of the N.officinale is 20.28 mg/kg,which can be applied to the selenium-enriched cultivation of N.officinale.2.Similar to traditional grafting,the prior grafting treatment can not only affect the photosynthesis,stress resistance and growth of N.officinale,but also affect the absorption,distribution and accumulation of selenium and nutrients.The effect varies depending on the rootstock.Among them,the chlorophyll a,chlorophyll b and carotenoid content of N.officinale increased by 28.52%,29.77% and 21.23%,respectively,after grafting with B.oleracea L.as rootstock.Moreover,the anti-oxidation enzyme activity and the content of the permeate can be increased to enhance the resistance of the N.officinale,and the MDA content is reduced by 31.92% compared with the ungrafted.It is most beneficial to the increase of biomass and nutrient absorption of N.officinale,which increases the biomassof shoot by 28.06% compared with the control.Therefore,prior grafting with B.oleracea L.as rootstock can improve the yield and quality of N.officinale,but has little effect on selenium-enriching ability.On the other hand,the prior grafting with R.sativus L.as rootstock is beneficial to the photosynthesis of N.officinale and can promote the increase of biomass.The soluble sugar content is the most beneficial to improve the quality,and can effectively improve the selenium-enriching ability of the N.officinale,and the selenium content in the shoot increased by 36.36% compared with the control.Prior grafting with B.chinensis as a rootstock makes the N.officinale have short stature characteristics.3.The grafting process has a superposition effect(with an upper limit).The secondary and tertiary prior grafting treatment with B.oleracea L.as rootstock can further enhance the photosynthesis of N.officinale,improve stress resistance and reduce stress.It also increased the root biomass of the N.officinale by 217.11% and 266.84%,and increased the shoot biomass by 173.23% and 211.01%,respectively,and promoted the absorption of nutrients and improved the yield and quality of N.officinale.On the other hand,secondary and tertiary prior grafting can effectively improve the selenium-enriching ability of N.officinale.In this study,both secondary and tertiary prior grafting achieved good results.Considering time and operating costs,the secondary prior grafting with B.oleracea L.as rootstock is more suitable for production applications.