Effects of experimental warming on vegetative and reproductive growth of Polygonum viviparaum in the Qinghai-Tibet Plateau

In arctic and alpine environments, low temperature is considered the most prominent limitation for the vegetative and reproductive growth of plants. Therefore, global warming is expected to have profound impacts on the plant performance of these areas. In the alpine meadow of the Qinghai-Tibet Plateau, we investigated Polygonum viviparaum, a perennial herb distributed widely in arctic and alpine regions, under two different levels of experimental warming treatments to examine effects of warming on its vegetative and reproductive growth. The results showed that the increased temperature promoted both vegetative and reproductive growth of P. viviparaum, but there was a significant tradeoff between them. Decreased reproductive allocation under warming suggested that more available resources were devoted to vegetative growth, resulting in increased plant height, leaf number and length of the longest leaf. After warming, the number and dry weight of flowers per spike decreased while the number and dry weight of bulbils per spike increased, indicating more investment to asexual reproduction over sexual reproduction in P. viviparaum. The increase of warming further strengthened the above variation trends of vegetative and reproductive growth of P. viviparaum.