西南典型半寄生植物毛叶钝果寄生的生物量分配研究

Studies on Biomass Allocation of a Common Mistletoe Species, Taxillus nigrans, in Southwest China

摘要:

为深入理解半寄生植物的生长发育特征及其生存策略，对西南典型半寄生植物毛叶钝果寄生(Taxillus nigrans)的生物量分配模式和异速生长特征进行了研究，并建立了以长度(L)或基径(BD)为自变量的个体生物量(TB)回归模型：TB= 0.0027L^2.3077，TB=134.99BD^3.334，TB=4.35L+8.34BD–183.85。结果表明，毛叶钝果寄生在幼龄和非幼龄阶段的生物量分配占比分别为叶>茎>吸器和茎>叶>吸器。在幼龄阶段，毛叶钝果寄生吸器和植冠(叶、茎和果实)间呈等速生长关系；在非幼龄阶段，各器官间的异速生长关系不完全符合异速分配理论，叶与吸器间的异速生长指数(1.01)显著高于异速分配理论的假设值(0.75) (P<0.001)，而茎与吸器间呈显著的异速生长关系(P=0.001)。毛叶钝果寄生独特的生物量分配模式以及异速生长特征有利于其对寄生生活的适应。

Abstract:

To further understand the growth development characteristics and survival strategies of semi-parasitic plants, the biomass allocation pattern and allometric growth characteristics of Taxillus nigrans, a typical southwestern semi-parasitic plant, were studied, and regression models of individual biomass (TB) with length (L) or base diameter (BD) as independent variables were established: TB=0.0027L^2.3077, TB=134.99BD^3.334, and TB= 4.35L+8.34BD–183.85. The results showed that the biomass allocation ratio of T. nigrans at juvenile stage and the nonjuvenile stage was leaf > stem > haumator and stem > leaf > haumator, respectively. At juvenile stage, there was an isometric relationship between haustoria and shoots (leaf, stem, and fruit). At nonjuvenile stage, the allometric growth relationships among the organs of T. nigrans were not consistent with the allometric biomass partitioning theory (APT), the allometric exponent (1.01) between leaves and haustoria was significantly higher than the predicted value from APT (0.75) (P<0.001), and there was a significant allometric relationship between stems and haustoria (P=0.001). The unique biomass allocation patterns and allometric growth characteristics of T. nigrans were beneficial to its adaptation to parasitic life.