荒漠植物白刺属4个物种的生殖分配比较

选定乌兰布和沙漠地区白刺属4种植物为研究对象,通过对其样株在花期的各生殖构件的数量特征及生物量调查,系统研究了唐古特白刺(Nitraria tangutorum Bobr.)、西伯利亚白刺(Nitraria sibirica Pall.)、大白刺(Nitraria roborowskii Kom.)和泡泡刺(Nitraria sphaerocarpa Maxim.)4种白刺属植物在生殖枝水平上的生殖分配。结果表明:不同白刺属植物在分株高度、生殖枝长、生殖枝基径、单枝花数、花序干重、枝叶干重等生殖构件的数量性状方面均有显著差异,其中泡泡刺的各生殖构件的数量均最小;除了西伯利亚白刺的生殖分配值达到44.51%外,其余3种白刺的生殖分配值均没有超过20%。经统计分析,4种白刺种群的生殖枝长分别与分株高度呈显著(P<0.05)的直线性正相关关系;生殖枝花序干重与分株高显著正相关;4种白刺的生殖分配随着分株生殖枝生物量的增加而减少,即白刺的个体大小与生殖分配之间呈现负相关关系。这种生殖分配特点反映了不同白刺植物对生长环境的资源利用、与克隆繁殖的权衡及对生态适应的策略。

Reproductive allocation in four desert species of the genus Nitraria L.

The reproductive characteristics of four plant species of the genus Nitraria L. in Ulan Buh Desert, Nitraria tangutorum Bobr., N. sibirica Pall., N. roborowskii Kom., N. sphaerocarpa Maxim., were studied. The reproductive allocation characteristics of reproductive tillers were studied based on measurements of the reproductive modules during blooming. The results showed significant quantitative differences exist in some reproductive modules of the four species, such as ramet height, reproductive tiller length, reproductive tiller diameter, number of flowers per tiller, dry weight of cymes, and dry weight of branches and leaves. Of the four plant species, N. sphaerocarpa was the smallest based on the above measured characters. N. sibirica allocated 44.51% of its mass to reproduction while the other three species allocated less than 20%. Statistical analyses were performed on the reproductive characteristics of four plant species. A significant linear correlation was found between reproductive tiller length and ramet height (P<0.05). The correlation coefficients were 0.8207, 0.7408, 0.8401, and 0.9144 for N. tangutorum, N. sibirica, N. roborowskii, and N. sphaerocarpa, respectively. The statistical significant test level of the curve fitness was 0.0067, 0.0224, 0.0046 and 0.0006 for N. tangutorum, N. sibirica, N. roborowskii, and N. sphaerocarpa, respectively. Also, the cymous dry weight was significantly correlated to ramet height. Specifically the absolute biomass allocated to the reproductive organs from the total biomass of the reproductive tillers increased as ramet height increased. The correlation coefficients of the two indices for N. tangutorum, N. sibirica, N. roborowskii, N. sphaerocarpa were 0.9283, 0.6631, 0.8350, and 0.8324, respectively. The fitted curves of the two indices for N. tangutorum and N. roborowskii followed a linear relationship, whereas that of N. sibirica followed a power law, and that of N. sphaerocarpa was quadratic. Third, the reproductive allocation of the four plant species decreased as the biomass of the reproductive tillers increased which represented the size of the plant. The fitted curves of the two indices for N. sibirica and N. roborowskii were linear, and those for N. tangutorum and N. sphaerocarpa were inverse. Plant size had a significantly negative correlation with the reproductive allocation. The characteristics of the reproductive allocation of four plant species of genus Nitraria reflect their strategies for the resource utilization and the trade-off with the clonal propagation and ecological adaptation to the environment.