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为探讨土壤碳氮比(C:N)对苹果(Malus pumila)植株生长和碳氮分配特性的影响,采用碳氮双标记示踪技术,以二年生平邑甜茶(Malus hupehensis)幼苗为试验材料,研究了6个不同土壤C:N处理(T1–T6分别为4.70、9.78、14.70、19.96、25.60和28.83)下平邑甜茶的生长状况和氮素吸收、利用分配以及碳水化合物的运转特性。结果表明,随着土壤C:N的逐渐增大,平邑甜茶幼苗根系干重逐渐增加,而株高、茎粗、地上部干重和植株总干重呈先增加后降低的趋势,以T4处理最大。土壤C:N显著影响了平邑甜茶幼苗的15N利用率,从T1到T4处理,植株的15N利用率逐渐升高,T4处理(18.46%)是T1处理(10.65%)的1.73倍;随着土壤C:N的进一步增加,植株的15N利用率逐渐降低,T5和T6处理分别比T4处理降低了1.59%和2.58%。土壤C:N较低的T1和T2处理,平邑甜茶幼苗各器官从肥料中吸收分配到的15N量对该器官全氮量的贡献率(Ndff)大小顺序为根>叶>茎,随着土壤C:N的进一步增大,叶片的Ndff均为最大,其次是根,茎最少。随着土壤C:N的增大,叶片15N分配率逐渐升高,13C分配率逐渐降低;而根系15N分配率逐渐降低,13C分配率逐渐升高。综合考虑植株生长和氮素利用状况,本试验条件下适宜平邑甜茶生长的土壤C:N为21–23。
In order to investigate the effects of carbon and nitrogen ratio (C / N) on the growth and C and N distribution of apple (Malus pumila) plants, the biennial Malus hupehensis seedlings were used as experimental materials. The growth status, nitrogen uptake, utilization and allocation of carbohydrates of Carmopolité chinensis under 6 treatments of soil C: N (T1-T6, 4.70,9.78,14.70,19.96,25.60 and 28.83, respectively) were studied. The results showed that with the increase of soil C: N, the root dry weight of the seedlings of P. euphratica increased gradually, while the plant height, stem diameter, aboveground dry weight and total dry weight of the roots increased at first and then decreased with T4 Deal with the largest. Soil C: N significantly affected the 15N utilization of P. euphratica seedlings. From T1 to T4 treatment, plant 15N utilization increased gradually, while T4 treatment (18.46%) was 1.73 times that of T1 treatment (10.65%); With the further increase of soil C: N, the 15N utilization rate of plants decreased gradually, while that of T5 and T6 decreased 1.59% and 2.58% respectively compared with T4 treatment. The T1 and T2 treatments of soil C: N showed that the order of contribution (Ndff) of 15N absorbed by fertilizer to the total nitrogen content of the organs was root> leaf> stem, Soil C: N further increased, the leaf Ndff is the largest, followed by roots and stems at least. With the increase of soil C: N, the distribution rate of 15N leaves gradually increased and the distribution rate of 13C gradually decreased. However, the distribution rate of 15N gradually decreased while the distribution rate of 13C gradually increased. Considering plant growth and nitrogen utilization, soil C: N suitable for the growth of P. euphratica under the test conditions was 21-23.