关键词: 凋落物量, 穿透雨减少, 叶面积指数, 胸径生长, 马尾松, 红锥

Abstract: Alcimandra cathcartii is a rare and endangered plant species, with important value in taxonomy and ornamental horticulture, and it is also a firstclass nationally protected species in China. Analysis of ISSR markers was conducted on three natural populations (NK, ZD and DHP) of A. cathcartii from Gaoligong Mountains National Nature Reserve with the objective of investigating the genetic diversity within and among the populations. Leaf samples of 62 individuals from the three populations were collected for DNA extraction. The results were as follows: (1) Fifteen ISSR primers were used to generate highly reproducible and stable DNA fragments (the sizes of ISSRPCR products ranged from 250 to 2200 bp). One hundred and eighty seven discernible DNA fragments were produced, among which 171 fragments were polymorphic loci (mean 12.5 bands and 11.3 polymorphic bands per primer). The percentage of polymorphic bands (PPB) was 91.44% at the species level, and PPB within population ranged from 21.93% (DHP population) to 66.30% (ZD population). (2) The genetic differentiation among populations was detected in A. cathcartii \[0.2294, 0.27 and 27% for Nei’s genetic coefficient of differentiation (G_st), Shannon’s diversity index and AMOVA\], which indicated that genetic differentiation mainly occurred within populations. The cluster analysis showed that the largest category included most individuals of the three populations. (3) The correlation coefficient (r=-0.519, P=0.323) obtained by Mantel test did not show any significant relationship between the matrices of geographical distances and pairwise genetic distances based on ISSR. On the basis of the genetic and ecological information, it is recommended that strengthening the nature reserve management and promoting the insitu conservation is a promising strategy for the protection of this species.

Key words: throughfall reduction, Pinus massonana, leaf area index, litterfall production, diameter growth, Castanopsis hystrix