Abstract:
In order to test whether P. densata was more fit in its own highelevation niche than its parental species (P. tabuliformis and P. yunnanensis) and describe their adaptative characteristics in the seedling stage,we conducted a comparative analysis of the seedling adaptative characters in three species. The results showed that most of traits in the seedling stage were significantly different among species and populations, and large amount of variance was identified among species or among populations. The survival rate and the rate of budset in October were the best indicators of amongspecies divergence. The hybrid pine P. densata appeared to be intermediate between P. tabuliformis and P. yunnanensis in most of traits in the early stage. Compared with P. yunnanensis, P. densata had higher germination rate and survival rate, which were lower than P. tabuliformis, and the budset date was 30 days later than P. tabuliformis. The hybrid pine P. densata expressed transgression in four traits of seedling height, the ratios of the red seedlings, the purple seedlings and seedlings of secondary growth, which would reflect its unique adaptation in the highelevation niche. P. tabuliformis was the highest in rates of budset and seedling survival. P. yunnanensis was lowest in seedling survival and only the twoyearold seedlings had signal of budset. P. densata had a longer growing season than P. tabuliformis, and stronger adaptation than P. yunnanensis. That could be one of the reasons about P. densata to become a hybrid in the highelvation habitat.