Reproductive allocation of dimorphic cleistogamous Viola tuberifera in alpine meadow of Qilian Mountain

Viola tuberifera, which endemic to Qinghai-Tibetan Plateau and its neighbor region, is a typical dimorphic cleistogamous plant. V. tuberifera conducts sexual propagation via both open, chasmogamous (CH) flowers and closed, obligate self-pollinating aerial and subterranean cleistogamous (CL) flowers. In present research, V. tuberifera in alpine meadow of Qilian Mountain within different altitude gradients during cleistogamous full-blossom period was chosen to investigate characteristics of reproductive allocations for understanding behavior of balancing propagation resource to adapt alpine environment. The results showed that: 1) Trade-offs existed not only in vegetation and reproduction，but also in aerial and subterranean cleistogamous flowers sexual reproduction, and probably in sexual and asexual reproduction; 2) Sexual reproductive allocation was sizedependent, and it was negative power exponent correlation between size and sexual reproductive allocation; 3) With the increase of altitude, it was declined drastically that individual size, total sexual reproductive allocation, and also descend in reproductive allocation of aerial cleistogamous flowers, while had a slightly elevated tendency in reproductive allocation of subterranean cleistogamous flowers and bulbs. Furthermore, the reproductive strategies were also changed with altitudes. In the low altitude(2 800 m), plants chose aerial cleistogamous flowers as major strategy, by contrast, preferring to subterranean cleistogamous flowers and bulbs in the high altitude. In a conclusion, the V. tuberifera may regulate reproductive allocations of aerial and subterranean flowers to gain maximum propagation success, adapting changes in high elevation and cold environment, ensuring survival and thrive of species in the alpine meadow ecosystem.