沙坡头人工固沙区一年生植物小画眉草繁殖分配研究

沙坡头人工固沙区不同始植年代一年生植物小画眉草(Eragrostis poaeoides)的繁殖分配研究。结果表明:无论在种群水平还是在个体水平上,都反映出:(1) 在不同的始植年代,个体大小与繁殖体大小均不相同,其排列顺序依次为1956年样地 > 1964年样地 > 1981年样地 > 1987年样地;(2) 在不同始植年代下小画眉草有性繁殖分配的大小存在差异,有的甚至达到显著或极显著的水平,小画眉草有性繁殖分配的大小与沙面固定的长短有关(大小依次排序:1956年样地 > 1964年样地 > 1981年样地 > 1987年样地),1956年固沙区小画眉草用于繁殖的投资比例达到(70.17±6.24)%,远高于1987年固沙区的(59.18±8.75)%。(3)地上营养器官生物量、茎重、叶片数和叶重在四个年代差异不显著,说明这些指标既受固沙时间长短的影响,也可能受其他因素的控制。通过研究,我们得到以下结论:随着沙面固定时间的延长,一年生植物生存的环境相对好转,一年生植物把更多的资源和能量用于繁殖,增加其种群规模;沙丘固定时间相对短的,一年生植物将把更多的资源和能量用于营养生长,以抵御不利的生长环境。

Reproductive Allocation of Annual Plant Eragrostis poaeoides in Planted Area for Sand Fixation in Shapotou Region

A field experiment on the reproductive allocation of the annual plant Eragrostis poaeoides was carried out in the re-vegetated areas in Shapotou of the Tengger Desert. The results reflected that for both the population and individual, the annual plant Eragrostis poaeoides has the different individual size and the reproductive size in re-vegetated areas with various time-duration from establishing, which may be listed as the sampling sites of 1956>1964>1981>1987; so did its sexual propagation, the size may also be listed as the sampling sites of 1956>1964>1981>1987, even the contribution rate of Eragrostis poaeoides to propagation was 70.17% 6.24% in site re-vegetated at 1956, far higher than 59.18% 8.75% of 1987 site; the aboveground biomass, stem weight, leaf number and weight almost had no difference in the four sites, which suggested that they were controlled by other factors besides by the fixation duration. The living conditions were improved with the increase of the stabilization duration. Hence, the annual plant will convert more resources and energy into reproduction activities, so as to increase the population size. In contrast, for the newly stabilized sand dune, the annual plant will consume more resource and energy for nutrition development in order to cope with the harsh environment.