EFFECTS OF PARENT RAMET SIZE ON CLONAL GROWTH IN NEOSINOCALAMUS AFFINIS
慈竹母株大小对克隆生长的影响

Clonal growth plays an important role in the population dynamics of Neosinocalamus affinis. In order to better understand the ecological adaptability of Neosinocalamus affinis at the individual level, we investigated the relationships between ramet size, rhizome size and shoot production. We measured the size of the parent ramet in terms of both basal diameter and biomass, the effects of parent ramet size on new shoot production, and new shoot and rhizome size of Neosinocalamus affinis . The experiment ran from June to November, 2000. We measured parent ramet size, new shoot size, new shoot number, rhizome size, mortality of new shoots, and the number of new shoots emerging and surviving at 9 plots in Xishan, Nanchong, Sichuan province. The data were analyzed by one-way ANOVA, independent-sample t-test and linear regression. The following results were obtained:1) The basal diameter of the primary and secondary parent ramet, but and average biomass of two-year-old and three-year-old parent ramets were positively correlated to basal diameter of surviving new shoots. But the effects of the primary parent ramet on surviving new shoots were more than the secondary parent ramet on, indicating that the basal diameter of surviving new shoots was size-dependent. 2) There were no effects of parent ramet size on the number of surviving, dead and emerging new shoots and the clonal population dynamics were probably affected by the number of parent ramets.3) The basal diameter of the parent ramet producing new shoots was larger than that of parent ramet not producing new shoots, suggesting that new shoot production was determined by a critical threshold size. Contrary to earlier conclusions, there was no significant differences in the basal diameter of the parent ramet producing one new shoot and the parent ramet producing more than two new shoots. The best basal diameter of the parent ramet was 6. 1 cm. 4) The length and diameter of rhizomes were positively correlated to basal diameter of the primary parent ramet and the average biomass of two year-old and three year-old parent ramets. Primary parent ramets affected shoot size through rhizome size because the rhizome stored critical resources. Our results showed that clonal growth in Neosinocalamus affinis was related to parent ramet size at the individual level indicating that shoot survival was most likely enhanced due to the higher availability of resources for investment into new shoots.