Responses Of Sexual Reproduction Pattern And Leaf Traits Of Arabidopsis Thaliana To Elevated CO₂

Atmospheric CO₂ concentration is expected to rise from current levels of about 370ppm to between 540 and 970ppm by the end of this century and the effects of rising atmospheric CO₂ concentrations on the global climate have attracted considerable attention. Because CO₂ is one of raw materials of plant photosynthesis, thus plant growth responds both physiologically and anatomically to elevated CO₂. So far, a great number of studies have investigated plant responses to elevated CO₂ at different scales ranging from ecosystem, community, population, plant, organ, tissue, physiological, biochemical to molecular levels, nevertheless few studies have focused on the effects of elevated CO₂ on plant reproductive characteristics and nearly no studies have reported the effects of long-term CO₂ on plant reproductive characteristics. It has been accepted that plant reproductive characteristics are key traits for predicting the response of communities and ecosystems to global change and are also closely related to its ecological fitness and production of crops. Furthermore, investigation on the long-term response of plant to elevated CO₂ under a completely man-controlled environment can increase our capacity to predict the properties of populations adapted to rising atmospheric CO₂ in the near future. Therefore, it is essential to carry out CO₂ selection experiments to investigate effects of long-term CO₂ on plant reproduction and adaptation of plant reproduction to elevated CO₂.In the present study, Arabidopsis thaliana, a model plant widely used in molecular, genetic, and developmental biology, was continously grown under both elevated (700ppm) and ambient (370ppm) CO₂ for eight generations. The changes in various reproductive characteristics of an individual generation were determined and their overall changes in eight generations were further invstigated. In addition, the changes in physiological, biochemical, and cytological traits of leaves of Arabidopsis grown udner both elevated and ambient CO₂ condition were compared. The main results and conclusions in this paper are listed as follows:Within an individual generation, elevated CO₂ advanced the flowering time of Arabidopsis through increasing relative growth rate and accelerating developmental process, and resulted in more flowers, more fruits, more seeds, more mass allocated...