Leaf Trait And Reproductive Traits Of Nine Common Species Of Plants At Eastern Alpine Meadow In Qinhai-Tibetan Plateu

It is expected an important effect of altitude on plant size, reproductive strategies within populations. Because of low temperature, short growing season and reduced insect abundance, plants at higher altitude in alpine ecosystems may adjust their reproductive strategies. There are a lot of unique plants in Alpine Meadow at Eastern Qinghai Tibetan Plateau. How to adapt the special environment of Alpine, and what reproductive strategies appear for these species, which provide special chance for ecologists and evolutionists. Therefore, we selected nine common insect-pollinated species which belonged to four families to study their reproductive strategies for understanding how these plants adapt to the environmental conditions. The results showed:(1) Total leaf area, plant size and total flower number were significantly positively correlated with each other, indicating that larger plants had a higher ability of resource acquisition. Special Leaf Area decreased with increased altitude, which was physiological adaptation for plants at high altitude, because thick leaf could protect the photosynthetic unit.(2) Flower traits and plant reproductive invest were affected significantly by altitude. The influences, however, occurred on different reproductive characters for different species, suggesting a species-specific adaptive strategies. Flower traits and reproductive invest increased with the increasing altitude in Lilium duchartrei, Lilium pumilum, Delphinium kamaonense var. glabrescens and Delpinium pylzowii. And flower traits and reproductive invest decreased with the increasing altitude in Parnassia oreophila, Lomatogonium carinthiacum and Lomatogonium macranthum. In Gentiana striata, the flower traits decreased but reproductive invest increased at high altitude. Reproductive allocation in every species increased at high altitude excluding Lilium pumilum. In general, insect diversity, abundance, and activity reduced at higher altitude in alpine ecosystems, and different plants adopted different strategies to adapt the environmental conditions. To compensate for assumed pollinator scarcity, individuals of Lilium and Delpinium at higher altitude might increase their effort to attract pollinators, but those of Lomatogonium and Gentiana might increase their self-crossing rates. (3)To a great extent, size-dependent flower traits, reproductive invest and reproductive allocation were found for any species at both altitudes. Reproductive traits were affected by both altitude and plant size, indicating that plants adjusted relationships between plant size and reproductive traits to adapt to varied environment.