Effects Of Elevated CO₂ Concentrations On Growth And Soil Microbe Of Tomato

Elevated atmospheric CO₂ concentration had a serious of influences on plant from greenhouseeffect. Photosynthesis of plant is based on CO₂, Increased atmospheric CO₂ concentration affectsplant not only their physiological, morphological and the distribution of biomass, but also roots andrhizosphere microbes in soil. The relationship between high CO₂ concentration and vegetablesshould be studied further at the present time. for the availability of optimize vegetable culturepractices and the developmental direction on further agricultural industry. One tomato finite-grownyueguang and one infinite-grown hezuog03 were taken as experimental material. Under high CO₂concentration, the change of biomass, photosynthesis, soil microbial biomass, microbial communitydiversity and soil respiration were detailed studied in this dissertation. Our study aimed to ascertainhigh CO₂ concentration, which affected tomato well balanced growth and soil microbes, in order toprovide experimental bases on the mechanism of plants ,which responded to elevated CO₂concentration. The main conclusions are shown as follows:1. Elevated CO₂ concentration notable restricted plant length, stem diameter, internode lengthand leaf number of tomato, promoted the distribution of dry weight to fruit, and decrease thedistribution of dry weight to stem and leaf , enhanced the nutrient growth and inhibited thegenerative growth, and improved yield and quality of tomato.2. 15 days exposure to elevated CO₂ concentration stimulates photosynthetic rate whilephotosynthetic acclimation may occur under 30 days exposure, photosynthesis rate increased againafter 45 days treatment. Short-term elevated CO₂ concentration has effects of lowering the stomataldensity, and stomatal conductance, with the prolongation of treatment , stomatal conductancebecame acclimation with high CO₂ concentration, and increased gradually, stomatal of hezuo 903adapted to high CO₂ concentration earlier than yueguang. The rule of transpiration movement wassameness with stomatal conductance, but reverse with cell concentration.3. Elevated CO₂ concentration notable promoted the Cmic, Nmic of yueguang; enhanced theCmic of hezuo 903, but Nmic increased not remarkable.4. Soil microbial community DNA diversities index was increased by elevated CO₂concentration for both yueguang and hezuo 903, but the reflect of hezuo 903 was more sensitivity;The effect of CO₂ enrichment on soil microbial community DNA evenness index of yueguang andhezuo903 were not remarkable; Elevated CO₂ concentration notable promoted soil microbialcommunity DNA richness index, yueguang was more sensitivity than hezuo 903.5. Elevated CO₂ concentration notable affected soil respiration of yueguang and hezuo 903, the trend of them were inhibited at the beginning of treatment, while were enhanced in the end .themovement range of hezuo 903 was wider than yueguang.Above all, elevated CO₂concentration had different influence on different breed of tomato ,butsumming them up, elevated CO₂concentration inhibited the plant growth of overground, whileenhanced the yield and quality of tomato, improved the soil entironment. Therefore, the effect ofelevated CO₂ concentration avail to plants.