The Study On The Ecological Response Of Desert Plant Under The Water Salt Gradient In Kenya River Basin

We selected natural growth Phragmites australis, Tamarix chinensis, Populus euphraticain Keriya River Basin for the study. In2012July11~August11measured Phragmitesaustralis, Tamarix chinensis s, Populus euphratica the photosynthetic physiology ecologicalparameters used the Li-6400portable photosynthesis meter. By analyzing the DiurnalPhotosynthetic of Phragmites australis, Tamarix chinensis, Populus euphratica to understandphotosynthetic rate trends of these three plants, and identify the main factors affectingphotosynthesis. Through artificial light intensity and CO2concentration, we explored thechanges of photosynthetic response characteristic parameters of Phragmites australis,Tamarix chinensis, Populus euphratica under different water and salt gradients. In order tostudy the mechanism of plant response to different water and salt gradients, we measuredphysiological components in different parts of the plant body. The research provides atheoretical basis for master photosynthetic mechanism of Phragmites australis, Tamarixchinensis, Populus euphratica. It is helpful to understand its requirement rules ofphotosynthesis to environmental condition and physiological adaptation mechanisms fordifferent environments, etc. Whether in theory or in practice has important instructionmeaning and reference value. Main conclusions are as follows:(1) The distribution of water and salt in Keriya River changed dynamically. It has acertain influence on the growth of plants in Keriya. Experiment places have been taken undera significant water and salt gradient. In different water and salt gradients, the plants havedifferent responses to water and salt conditions.(2) The Photosynthesis of Phragmites australis primarily related to photosyntheticallyactive radiation, temperature and relative humidity. When subjected to salt stress, Phragmitesaustralis will adapt to stress by increasing photosynthesis. When high salinity, Phragmitesaustralis not only maintain a higher utilization of low-light and strong photosynthetic capacity,but also affect the lower utilization of CO2. At low water, Phragmites australis reduce the utilization of low-light, but a wider range of CO2.(3) The photosynthesis of Tamarix chinensis is closely related to photosyntheticallyactive radiation. When the degree of water and salt content is moderate, the photosynthesis ofTamarix chinensis also related to temperature and Intercellular CO2concentration. Tamarixchinensis adapt to stress by improving photosynthesis. Under high salt conditions, tamariskphotosynthetic structures have been destroyed, resulting in a reduced ability of photosynthesisand CO2response characteristic parameters also shows tamarisk severely stress and affectingthe normal growth. At low water, Tamarix chinensis improve photosynthetic capacity, butimpact the utilization of low CO2concentration.(4) The photosynthesis of Populus euphratica is related to photosynthetically activeradiation. When higher water and salt content, the photosynthesis of Populus euphratica alsoclosely related to temperature and relative humidity. At lower water and salt content,photosynthesis of Populus euphratica is inhibited, and the daily average minimum and mainlyaffected by moisture. At the lower water, the capability utilization of low-light is weak andlower photosynthetic capacity. When moisture conditions were better, photosynthetic productsof Populus euphratica could be better accumulation.(5) The change in physiological indices is different between different species, butgenerally consistency. And physiological indicators respond to the environment is also a slightdifference in the different parts. Phragmites australis mainly effected by the combined of saltand water. The impact of salinity on Tamarix chinensis is more obvious. The main factor ismoisture on Populus euphratica. The relationships of affect Factors and physiological indicesof plant and the plants themselves have great relevance.