Effect Of Cd Treatment On Growth And C、N、P Accumulation Of Cinnamomum Longipaniculatum Seedling

With the development of industrialization and urbanization, cadmium (Cd) pollution in city is more and more serious which has critical effects on urban ecological environment. Phytoremediation is used in Cd polluted environment, which is a hotspot in research of environmentology and biology at present. In recent years, hyperaccumulator is widely taken as Optional plants in phytoremediation process. Hyperaccumulator can accumulate more Cd, but the species are less, the growth is restricted by environment factors and the feature of city garden landscape is lack, which further influenced introduction and cultivation of garden trees with characteristics of ecological restoration. In this paper, potted experiment was used to study the effect of different Cd concentrations in purple soil on the growth and C,N, P accumulation of Cinnamomum longepaniculatum (Gamble) N. Chao ex H. W. Li (CL) as well as Cd migration and distribution, which provided certain scientific basis for making in noxious use of Cd polluted soil, construction of urban garden forest and research of phytoremediation technology. The results showed that:(1) With the increase of Cd concentration treatment, height, ground diameter and individual biomass growth of GL gradually decreased, and the ratios ground and underground biomass also showed the declining trend. The growth of height, ground diameter and individual biomass, and root, stem and leaf biomasses of GL at middle (T2) and high (T3) Cd concentration treatment were obviously lower than that of0(CK) and low (T1) Cd concentration treatment. The biomasses of roots and stems were significantly higher than that of leaves at CK, while there were few differences in the biomasses of roots, stems and leaves between T1, T2and T3treatments, and the ratios ground and underground biomass among the different treatments.(2) We observed that significant differences in Cd concentrations and contents in soil among the four treatment before CL planting, and the extremely differences after a growing season. There were no significant differences in reduction of Cd concentrations and contents in soil between the CK, T1, T2, and T3treatments, while absolute value of the reduction increasing with the increase of Cd concentration treatment. Additionally, Cd accumulations of GL and leaf litters at T1and T2treatments were extremely higher than that of CK and T3treatments, especially the Cd reduces in soil, the Cd accumulations of GL and contents of Cd from leaf litters entering into the soil were the most. Meanwhile, Cd accumulations of leaves were significantly lower than that of roots and stems at CK, T1and T2treatments, while there were few significant differences in Cd accumulations of roots, stems and leaves of GL at T3treatments. Cd accumulations of roots, stems and leaves and individual GL at T1, T2, and T3treatments were obviously higher than that of CK treatment. The highest Cd accumulations of every part of GL were389.92μg·single plant-1(root),412.80μg·single plant-1(stem),268.71μg·single plant-1(leaf) and1071.43μg·single plant-1(individual) at T1treatment, while the lowest at CK treatment compared with other treatments. There were no significant differences in the ratios ground and underground Cd accumulations of individual GL among the four treatments, but the ratios showed the increasing trend with the increase of Cd concentration.(3) C and N accumulations of individual GL showed the declining trend with the increase Cd concentration, especially the C、N and P accumulations at T2and T3treatments were significant lower than that of CK and T1treatments. Moreover, the highest C accumulation of individual GL at CK treatment was29.16g-single plant-1, while the lowest at T2treatment was7.36g-single plant-1; the highest N at CK treatment was286.78mg-single plant-1, while the lowest at T2treatment was68.54mg·single plant-1; the highest P at T1treatment was54.87mg-single plant-1,while the lowest at T2treatment was14.39mg-single plant-1. Meanwhile, C、N and P accumulations of roots, stems and leaves of GL at T2and T3treatment were significantly lower than that of CK and T1treatments. Few significant differences in C accumulations among any parts of GL at T1, T2and T3treatments were detected, but the C accumulations of stems were obviously higher than that of roots and leaves at CK treatment. The N accumulations of leaves were significantly higher than that of roots and stems at CK treatment, while the N accumulations of stems were obviously lower than that of roots and leaves at T1,T2and T3treatments. We also investigated that few significant differences in the P accumulations of roots, stems and leaves at CK, T1, T2, and T3treatments. There were no significant differences in the ratios ground and underground C and P accumulations of individual GL among the four treatments, while the ratios of C decreasing and P increasing with the increase of Cd concentration. Otherwise, the ratios of N at T3treatment were obviously lower than that of CK treatment.In conclusion, GL could efficiently adapt to low Cd concentration contaminated environments, and paly an important role in Cd of adsorbing and accumulating. However, growth and absorbtion and distribution of nutrient of GL were obviously influenced by higher Cd concentration, which further effecting the Cd adsorbing process of GL. Thus, these results not only provide certain scientific evidence for research of physiological mechanism of plant under heavy metal stress, but also make important meanings to landscaping in city area with heavy metal pollution.