Study On The Patterns Of Survival And Reproductive Strategies Of Halenia Elliptica In The Different Altitude Gradient

As an environmental factor, altitude gradient has a great influence on morphological characters and reproductive traits. And plants have adaptation mechanisms to varied environments. Halenia elliptica is a common species in the eastern Tibetan plateau. We sampled Halenia elliptica along with elevation, and used comparative analysis to evaluate differences of morphological characters and reproductive traits, which aimed to study its morphological and reproductive strategies in various altitude gradients and examined how environmental factors contribute to species evolution. It is important bases to study trade-off of energy in different properties of life cycle, and morphological and reproductive strategies under extreme conditions. Results showed: ⑴ Individual size, leaf number per plant, leaf mass, leaf area, leaf area index and specific leaf area all decreased along with elevation. When the effect of individual size was controlled statistically, significant negative correlation was found between elevation and leaf number per plant, leaf mass, leaf area, leaf area index, specific leaf area. ⑵ With elevation increasing, flower number per plant, flower mass, fruit number, fruit mass and seed mass per fruit all decreased, while germinated seeds number increased. When the effect of individual size was controlled statistically, there was also significant negative correlation between elevation and flower number per plant, flower mass, fruit number, fruit mass, seed mass per fruit. ⑶ Reproductive allocation and reproductive export all increased along with elevation. When the effect of individual size was controlled statistically, reproductive allocation and reproductive export were negatively related to elevation as well. Annual plants have diminishing resources along with elevation, so they have specific trade-off of energy: reducing energy consumption of growth, increasing energy allocation for reproduction and produce more germinated seeds, to maintain population stability and adapt to different habitat.