Reproductive Strategy Of Viola Tuberifera Endemic To Qinghai-Tibetan Plateau

Clonal plants have baecame a relatively independent research filed and the research on them are mainly limited on the obvious impacts caused by their clonicity, i.e., the flexibility for physiological integration, foraging behavior and architecture of stolon and tubers. However, there are few reports on the reproductive strategies of clonal plants, and resource allocation strategies of two reproductive modes under natural state, which affect the adaptive evolution and genetic aspect of clonal plants.The reproductive strategies of Viola tuberifera endemic to Qinghai-Tibetan Plateau was investigated here. The sexual reproduction mode and efficiency, seed germination characteristics and its adaptability, the ability of clonal propagation and its adaptation to heterogeneous resources, biomass allocation and the trade-offs of vegetative growth and reproductive growth as well as sexual and asexual propagation were analysed in order to elucidate the reproductive strategies and its adaptation to the environment of Qinghai-Tibetan Plateau of Viola tuberifera. The conclusions are as follows:1. Viola tuberifera has various types of sexual propagation and amphicarpy. Three types of seeds, i.e., CH seeds, aerial CL seeds and subterranean CL seeds can be produced but the latter two seeds are the main types. CH seeds and aerial CL seeds are dispersed mainly through capsule cracking and ant removal, subterranean CL seeds undertake active proliferation via stolon. These disperse mechanisms ensure the germination, growth and propagation of Viola tuberifera. The germination rate of the different seeds have lower germination rate because of dormancy and that of different seeds are greatly different. Low temperature (5℃) are helpful to the seed germination of Viola tuberifera. The characteristics of sexual propagation make Viola tuberifera adapt to the environment of Qinghai-Tibetan Plateau.2. Viola tuberifera can carry out clonal growth through bulbs, rhizomes, spacers and new bulbs from stolons, however the remats mainly produced through the new bulbs from stolons which avoids the threats from colder winter and decreases the feath rate of remat. Viola tuberifera responses to the external environments more obvious, in the low altitude areas, there are more stolon and the clonal architecture tends to phalanx. While the quantity of stolon decreases, the branching angle increases and the clonal architecture tends to guerrilla in high altitude. In the heterogeneous resources, Viola tuberifera changes the motphological parameters of stolon and bulbs so that it could put the feed site into rich microhabitats, put the bulbs into proper micropatchs. Therefore, all of these help the bulbs obtain the resources and determine the function of remats.3. The propagation allocation of Viola tuberifera responses to the heterogeneous resources significantly. The propagation allocation tends to sexual propagation in the complex community and rich habitats, however, in the simple community and poor habitats, it tends to asexual propagation. With the increase of altitude, the biomass allocation to sexual propagation decreases gradually while that to clonal growth increases. There are no regular patterns between biomass and altitudes. The biomass is dependent on the resources, and showed a reverse ration relationship with vegation coverage and a direct ration with resources. In the CH fruit period of Viola tuberifera, the biomass trade-offs can be detected, such as trade-offs between the root and the stem and leaf, the root and the sexual propagation, the sexual propagaton and the clonal growth. The trade-offs among modules of Viola tuberifera in the CL fruit period are still unclear, however.