Effects of Light and Nutrient Treatements on Three Plants of Saussurea DC. on the Eastern Alpine Meadow of Qinghai-Tibet Plateau

Light and nutrients for plant growth, survival and reproductive success have an important impact. For what kind of reproductive strategies in plants living in the alpine region will take to protect their reproductive success has attracted the attention of many scholars. Eastern Tibetan Plateau the special alpine meadow vegetation type contains many unique plant groups, how plants adapt to unique environmental conditions of the Qinghai-Tibet Plateau, showed what kind of reproductive strategies in reproductive ecologists, evolutionary biologist provides a unique research opportunity. In this paper, the controlled experiment is a germination rate of plants on the eastern Tibetan Plateau alpine meadow on three common Asteraceae Saussurea seedling survival and breeding phenology, reproduction, distribution, inflorescence and seed characteristics as well as their size and number of conducted a study on the relationship between aspects of plant breeding countermeasures taken in extreme environments, and possible mechanisms. The results showed that: 1. Illumination of three wind Saussurea species emergence and seedling survival significantly affect the nutritional impact was not significant. Shade conditions favor Saussurea species emergence and seedling survival of plants, high-intensity light inhibition of plant emergence or seedling survival. Three Saussurea genus of flowering phenology under different light conditions change significantly, while little change under different nutritional conditions. Shade delayed flowering, flowering duration shortened. Accordingly, the three species in the shade under the conditions the results of time have postponed Saussurea species with the nutritional conditions of reduced performance postpone a result of time, which led to increased seed abortion rate. Light, nutrition significantly affect the three Saussurea are of plant inflorescence and seed characteristics, but different species respond to different modes. Saussurea and purple bud Saussurea produced under conditions of light, lower nutrient levels less large inflorescence and seeds, and flowers Saussurea choose to produce a large inflorescence and seed under conditions of reduced light levels, but under the conditions of reduced nutrient levels to choose to produce small inflorescence and small and few seeds. Whether in the flowering or fruiting stage, lower nutrient levels of the three Saussurea genus plant reproductive allocation showed a downward trend; different light on the distribution of three species breeding performance Saussurea hair and purple bud Wind daisy in the shade under the condition of reproductive allocation reduced, while the flowers Saussurea increased reproductive allocation in shade conditions. Interspecies differences in response pattern may be related to adapt to the different distribution of the natural environment. 5 Saussurea and purple bract Saussurea inflorescence number and size, seed number and size, there is a trade-off relationship between the size and the number of trade-offs and resource conditions, exacerbated by a lack of resources that this trade-off relationship. The daisy flowers Saussurea order, the positive correlation between the number and size of the seed, but does not depend on the level of resources, did not show the size - the number of trade-offs. Saussurea and purple bract Saussurea that plant reproductive strategies in the trade-off between dependence on environmental resources, they are able to respond to changes in the external environment, and by the adjustment of breeding inputs fitness maximization is an adaptive countermeasures. , Flowers Saussurea reproductive strategies in no trade-off relationship also shows that the adaptation of the species to shade environment.