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

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.