Effects Of Water Deficit On Canopy Photosynthetic Properties Of Every Green Organs In Cotton

About more than 95% of crop biomass is come from photosynthetic products,photosynthesis is the basis of crop yield. Leaves are the main photosynthetic organs for crops,however, many non-leaf green organs and tissues of crop are also with photosynthetic capacity, because some of them contain or can produce chlorophyll, photosynthesis in these plant parts can make a significant contribution to yield. Therefore, study of the photosynthesis of non- leaf green organs would be significant. This research was conducted using different irrigation treatments to research photosynthesis characteristic of leaves and non-leaves green organ in cotton, structure index of canopy, contribution of light and yield. This research indicated that it was important significance for moderate water stress to yield formation. The research not only provides a theoretical basis for high yielding cotton production and drought-tolerant cotton breeding, but also play a green organs photosynthetic capacity.1. At the different water treatments, light transmittance was increased with the reduce of drip irrigation amount in cotton. Compared with the conventional drip irrigation amount,canopy photosynthesis of leaves and non-leaf green organs reduced with the quantity of drip irrigation amount reduction, and the index of leaf area were also reduce. Chlorophyll of per unit area decreased slowly in non-leaf green organs(bract, bell, stem) of cotton under water deficit.The research indicates that non-leaf green organs had strong resistance and tolerance to drought stress. It can maintain a relatively stable photosynthesis. Specifically, non-leaf green organs promote the growth of plants. Finally, it improve the yield of crops. Therefore non-leaf green organs play an important role in photosynthetic material production crop.2. In same condition of drip irrigation treatment, upper canopy become a key source of photosynthetic C. With the development of growth period, the leaf population decline quickly in photosynthetic capacity, but bracts and stem group photosynthetic rate relatively stable.That photosynthetic capacity of green organs response of soil water deficit is not very sensitive relative to the blade in cotton. Under different irrigation amount, the groups photosynthetic values of green organic in the upper canopy above the middle and lower part at different positions of the canopy, in the present production cotton, moderate water deficit increased lower canopy photosynthetic capacity and biomass leaves of leaves in cotton. Under the water stress, CAP showed a unimodal curve with the growth stages under different water treatments, and the canopy photosynthesis decreased with reduce of drip irrigation. At the light conditions in the field, the light interception were increased with the reduce of drip irrigation amount.3. Photosynthetic area and rate of non-leaf green organs reduced slowly under different water treatments in cotton. Ratio of leaf and non-leaf green organs to the total surface area of cotton plant grown and surface area of the plant increased with the quantity of drip irrigationreduction. Biomass accumulation of non-leaf green organs were increased at the moderate water deficit in cotton. But the boll number and seed cotton yield decreased with the quantity of drip irrigation reduction in each cotton under different water treatments, the proportion of biomass accounted of Leaf to the total biomass decreases with the decrease of water supply,rather than the rates of non-leaf green organs, especially boll and stem increased. The moderate water deficit increased the biomass accumulation of non-leaf green organ accounted for the proportion in the total biomass accumulation.