The Effects Of Water And Soil Environment On The Growth Of Populus Euphratica Seedlings

The low survival rate of Populus euphratica seedling was the key problem of the update and artificial breeding. The study began in May 2013 and ended in September 2014. Effect of soil and water was obvious to seedlings, so the reflection of P. euphratica seedling growth on the environment directly influenced seedling survival and updated dynamically of P. euphratica populations. This test was adopted by moisture, nutrients, salt and illumination. We analysed the response of Populus euphratica seedling to the environment under different gradients, to discuss what were the factor affecting obviously Populus euphratica. The results showed that:(1) Response of over-ground growth of Populus euphratica seedling to moisture content tended to be consistent with the root growth, but the sensitivity to drought stress was lower, and the water demand was higher. Drought stress caused the increase of root to shoot ratio to adapt to the arid environment. The ability of 2 year old Populus euphratica seedlings’over-ground part to adapt to drought stress was stronger, increasing soil moisture content could promote the growth of seedlings. (2) Populus euphatica seedling adapted to the arid environment through the establishment of herringbone-likebranching patterns, increase of the vertical longitudinal extension ability. When the soil moisture content increased, seedling’s root tended to be dichotomous branching patterns and increase ration of width to depth. The 1 year old Populus euphratica seedling was sensitive to water stress. Drought stress or excessive moisture content may inhibit the growth and development of 1 year old Populus euphratica seedling’s root. The 2 year old Populus euphratica seedlings decreased sensitivity to drought stress, and increased demand for water root. (3) The damage of salt on Populus euphratica seedling started from the root, then spread to the over-ground part. Seedlings with high salt conditions cannot survive, salt stress could inhibit the growth of Populus euphratica seedlings and even lead to death. (4) The 5-factor 4-level orthogonal test was designed to discuss how to induce root growth:the factors included density, irrigation, fertilization and fulvic acid. Water treatments had a significant effect on root biomass, root length and root surface area. Root length and root surface area was most developed under the 15% water content with continuouswater treatments. N, P had a significant effect on the root surface area, and high concentrations inhibit root growth. Fulvic acid promoted the development of root length and can be applied to the artificial cultivation of Populus euphratica seedling.We concludedthatPopulus euphatica seedling adapt to the arid environment through the establishment of herringbone-likebranching patterns, increase of the vertical longitudinal extension ability and root to shoot ratio. The sensitivity of early seedlings to water stress is higher, seedlings can only survive in the appropriate soil moisture conditions. Along with the growth period of seedling growth, to sensitivity to water stress was reducing. By applying different concentration of water and fertilizer to different growth period of Populus euphratica seedling, we can induce the growth of root, stem or leaf of Populus euphratica seedling, the study has an important guiding significance for the artificial cultivation.