关键词: 碳分配, 引进树种, 乡土树种, 适应策略, 叶龄, 枝龄

Abstract: Seasonal variations of non-structural carbohydrate (NSC) contents in different organs of 40-year-old Pinus tabuliformis and Pinus densiflora were analyzed in Horqin Sandy Land, and the carbon allocation and utilization strategies of the two species were compared, which is of great significance to the selection of afforestation tree species and sustainable management of protective forests in Horqin Sandy Land. Results showed that starch contents in branches and roots of P. densiflora were higher than those of P. tabuliformis in April. From April to June, soluble sugars and starch contents of P. tabuliformis decreased in 1- and 2-year-old needles, but varied less in 1- and 2-year-old branches; the content of soluble sugars increased while starch content remained stable in roots. The contents of soluble sugars, starch and NSC in 1- and 2-year-old needles and branches, and roots of P. densiflora decreased. From June to August, for P. tabuliformis, soluble sugars contents increased in current-year branches and needles but decreased in 1-year-old branches and needles, and roots; however, for P. densiflora, contents of soluble sugars, starch and NSC, and ratios of soluble sugars to starch in needles with 3 age classes remained stable, while soluble sugars contents increased in current-year branches but decreased in roots. From August to October, soluble sugar content decreased in roots of both species, whereas it remained unchanged in P. tabuliformis branches, but increased in P. densiflora branches. These results indicated that P. tabuliformis had relatively lower NSC storage for growth. P. densiflora had higher NSC storage during the dormant period, resulting in faster growth of branches and needles, and thus more NSC production during the growing period, and more NSC distribution to branches and roots for growth at the late growth period, which can be better adaptive to the habitat of Horqin Sandy Land.

Key words: carbon allocation, introduced tree species, native tree species, adaptive strategy, needle age, branch age