The Growth Characteristics And Influence Factor Of Populus Euphratica Seedling’s

When soil moisture conditions change, Populus seedlings to adapt to habitat will to survive by adjusting the ground and underground growth strategy, showed a strong growth and configuration of plasticity.The 1--2-year-old seedlings of trade-offs and configuration significantly affect their own survival and root expansion. For the biennial seedlings, the growth characteristics and distribution strategy may be the key to its survival and morphogenesis. In this study, four key factors for Populus seedling growth-water conditions, explore the soil moisture changes, water supply and how it affects the way the ground and underground distribution and weigh seedlings,to provide a theoretical basis for artificial breeding, introduction and cultivation management.Test in Ejina,Beijing Wenquan nursery and Dadongliu nursery. An experiment with two different watering treatments was carried out on the biennial seedlings of P. euphratica. The seedlings’ aboveground growth indices (basal diameter, crown width, height, number of leaves) and underground growth indices (total root length, total root surface area per unit square meter of soil total root length, total root volume) were monitored to analyze the effect of different watering treatments and water gradient on growth tradeoff of the seedlings. The results showed that, for the growth of aboveground parts of seedlings, a soil moisture content of 25% was optimum water condition under continuous watering, but under the intermittent watering treatment, a soil moisture content of 30%was most suitable. There was a significant difference in seedlings’underground growth under different watering treatment, and a soil moisture content of 25% was significantly different from other levels and more beneficial to root growth. After drought stress, the intermittent water supply was more favorable to root growth than the continuous water supply, and soil moisture content of 20% to 25% was more suitable to root biomass accumulation. When seedlings were subjected to drought stress, the accumulation of underground part biomass was more than that of aboveground parts, and the trade-off effect between the underground and aboveground growth was more conducive to the nutrients and water allocation to the longitudinal growth, but the lateral growth of roots was increased more with enough water supplyIntroducing in Ejina forest farms selecting seedlings planted in Beijing nursery, seedling growth monitoring the adaptation and phonological to analysis adaptability of Populus seedlings in Beijing. The results showed that:Populus in the Beijing area is completely introduction survived, and higher survival rate can be made to more than 70%, and grow faster. In a single growing season,90% of the total plant height can grow more than 30 cm and diameter more than 1.5 mm.So Populus euphratica is a quick-growing species. Populus seeds can germinate in the Beijing area also, and higher germination rate, seed is more appropriate for sandy soil germination and growth.