关键词: 柳杉, 细根衰老, 养分内循环, 养分迁移

Abstract:

The fine roots of Cryptomeria fortunei were excavated from soil in order to accelerate the root senescence. The concentration changes of N, P, K, Ca in different order fine roots of Cryptomeria fortunei were measured in the course of senescence. The results showed as follows:1) There was obvious inner circle of N and K, however not significant inner circle of Ca, and no any inner circle of P, during dying of the fine roots. 2) The inner circle of nutrients firstly appeared in the 1st order roots, followed by the 2^nd order and the 3^rd order roots, which suggested the sequence of caducity and death was reverse to that of growth. 3) The nutrient flow exited different phases, that is, nutrients flowed from the 1^st order to the 2^nd order then to the 3^rd order of fine roots. 4) There was the same change trend between the concentration of N,P and K and the ratios of N /Ca, P/Ca and K/Ca , which suggested Ca could be as an indicator of other elements as far as inner circle were concerned .

Key words: Cryptomeria fortunei, fine root with senescence, nutrient internal cycling, nutrient remove