氮添加对稀土尾砂地猴樟幼苗根系生长、生物量分配及非结构性碳水化合物的影响OACSTPCD

In order to explore the effects of nitrogen addition on the growth and non-structural carbohydrate(NSC)content of Cinnamomum bodinieri seedlings in rare earth mine tailings,one-year-old C.bodinieri cuttings were used as materials,and calcium ammonium nitrate was used as nitrogen fertilizer(containing N 15%),and three nitrogen levels(CK(0),N1(1.8 g per plant),N2(3.6 g per plant))were set up to analyze the differences in root growth,biomass distribution and NSC of C.bodinieri seedlings under three nitrogen addition levels,and to explore the response of C.bodinieri in rare earth tailings to nitrogen addition.The results showed that:Nitrogen addition increased the biomass accumulation of different tissues of C.bodinieri seedlings in rare earth tailings,and the leaf biomass and canopy biomass at N1 level were significantly increased by 44.75%and 57.43%(P<0.05),respectively,compared with N2.Compared with CK and N1 treatment,the leaf mass ratio of N2 level was significantly increased by 123.53%and 15.85%(P<0.05),respectively.Nitrogen addition significantly promoted the root length and root surface area of both coarse roots(diameter>2mm)and fine roots(diameter≤2mm)(P<0.05),and the promotion effect of N1 treatment was the most significant(P<0.05).The specific root length and specific surface area under N2 treatment were higher than those of CK and N1,and significantly different from CK(P<0.05).For NSC,N1 treatment increased the soluble sugar mass fraction in leaves and stems,while the NSC mass fraction of fine roots under N2 treatment was significantly lower than that of CK and N1 by 46.49%and 28.61%,respectively.In summary,during vegetation restoration in rare earth mine tailings,1.8 g per plant calcium ammonium nitrate fertilizer might be suitable for fertilization management of C.bodinieri seedlings.