九寨沟自然保护区4种水深梯度下芦苇分株地上生物量的分配与生长

芦苇是世界自然遗产--九寨沟自然保护区的一种重要的湿地植物.本文对该地区芦苇海4个不同水深梯度下芦苇的无性系地上分株的生物量分配、生长与繁殖策略进行了比较研究.结果表明,在47 cm (水在土层表面上)水深环境中,芦苇单株的平均生物量(4.2 g)最大.在-15 cm (水在土层表面下15 cm)的生境中,叶生物量百分比(叶生物量占单株总生物量的百分比, 46.1%)最大.芦苇地上分株高度、地上分株有分枝的单株百分比(茎上有分枝的分株占样地总分株的百分数)也存在明显的差别.茎的生物量分配百分比和生长速率随水深的增加而增加.在滩地生境中,开花率、花序的生物量百分比明显大于水较深的生境.分株株高与分株生物量、茎生物量与叶生物量都表现出较明显的幂指数异速生长规律.在-15 cm水深的生境中,叶生物量的生长快于茎的增长;在其他水深梯度的生境中,则是茎生物量的增加快于叶生物量的增加.

Aboveground Biomass Allocation and Growth of Phragmites australis Ramets at Four Water Depths in the Jiuzhaigou Nature Reserve, China

The Jiuzhaigou Nature Reserve is a world natural heritage site in northern Sichuan, China, where an important wetland plant, Phragmites australis grows. The populations of P. australis from four different water depths in the Nature Reserve were compared for their aboveground biomass allocation, growth and reproduction of the single ramet. The results showed that the average aboveground biomass of a single ramet (4.2 g) was the largest in the habitat with water level of 47 cm above the soil surface. At the habitat with water level of 15 cm under soil surface (-15 cm), the leaf biomass percentage (of the total ramet biomass) was the largest (46.1%), and the height and percentage of ramose ramets (with branches on stem)(of the total ramets in a plot) were found obviously different. The deeper in water, the larger the biomass percentage and growth rate of stems were. The flowering rate and biomass of panicles were greater in shallow water than those in deep water. P. australis showed allometric growth for the height of ramets, and their biomass, stems and leaves by the power function. At the habitat with water level 15 cm under soil surface, the growth of leaf biomass was faster than that of stem biomass, and this was contrary to the growth at other water depths.