Reproductive Allocation Strategies Of Gentiana In The Eastern Of Qinghai-Tibet Plateau

The mode of resources allocation can reflect the character of the plant life history, which is central to study of plant life history. Studies on resource allocation were focused on two aspects: sex allocation and reproductive allocation. Sex allocation is about optimal allocation of reproductive resources between the male and female; Reproductive allocation is about the ratio of reproductive resources in total, the factors which influence the ratio, and the relationship between the ratio and the influence factors.There are a lot of unique plants in Alpine Meadow at Eastern Qinghai Tibetan Plateau. How to adapt the especial environment of Alpine, and what reproductive strategies appear for these species, which raised great interest of breeding ecologist and evolutionary biologist. Therefore, we selected common species of Gentiana, which has widely distribution at eastern of Qinghai-Tibet Plateau, studied the resource allocation strategies, especially the correlation between reproductive strategies and various influencing factors, to understand how the plants adapt to the especial environmental condition. The results showed that:(1) The larger of individual size, the higher of reproductive investment and both floral display size and total flower production are increasing with plant size , the flower number is increasing more remarkably than flower size. But there was not certain correlation between reproductive allocation and size of individuals, which suggest species-specific adaptive strategies. For perennial plants of Gentiana, with increasing of individual size, female function investment, male function investment and attractive structures investment increase. It can ensure that all the resource will be available fully without waste due to the increasing of a single part;(2)There are four results of sex allocation in the six kinds of perennial gentiana concordant with SDS theory prediction, that is to say, the larger individual allocates more resources to female function. The sex allocations of Gentiana atraminea and Gentiana dahurica Show no negative correlation with the individual size may be related to the Dichogamy-Protandry;(3)The distribution between female and male function of resource show no trade-off. It maybe caused by the truth that the resource distribution of plant must be under diverse life history character, not one kind with another. The trade-off between total flower production and flower size is exist after controlling for plant size statistically. This result confirms the theory predicts;(4) The positively correlated between individuals size,reproductive investment and altitudes, except plant size of Gentiana Choanantha. It means that plants of Gentiana tend to increase the plant size and reproductive investment to adapt the varied environment. Influences induced by high altitude on the reproductive allocation vary by species, which suggest species-specific adaptive strategies.(5) In this work, with the altitude increased the pollen/ovule ratio of perennial gentiana reduced, and the shortages of pollinators at a high altitude may be the main pressure for forming this breeding system countermeasure changes. Moreover, except Gentiana atraminea, the variety of the amount of flowers has little influence on the altitude increased, but the size of flowers is trending up. This shows that the plant of gentian usually favored male fitness on male and female reproduction fitness which is represented by flower size and flower number.(6)The proportion of reproduction allocation of gentiana shows a tendency to increasing gradually from original species to evolution species. It means that the higher development of species, the more devotion for reproduction. Comparing with perennial gentiana, the proportion of reproduction allocation of annual gentiana has risen notably. It means that the annual plants usually pay more attention on the reproduction output to gain maximum fitness during its limited life cycle.(7) For the pollen/ovule ratio, the perennial gentiana is higher than annual gentiana. Excepting the two species of Sect. Cruciata, the pollen/ovule ratio of other species of perennial gentiana increased by higher development. The annual gentiana also has the same feature. It means that the pollen/ovule ratio of gentiana also associated with its phylogeny level. The exception of Sect. Cruciata maybe related on that the two species which are studied by us are cyme.