Charactertics Of Root Suckers Of Populus Euphratica And Influencing Factors Along The Aqikesu River Bank In Ebinur Lake Nature Reserve

Populus euphratica is a woody plant in the family of Salicaceae, it is a main tree species in Ebinur Lake Nature Reserve. The asexual reproduction by means of root sucker is one of important regenerate approaches for Populus euphratica in this area. In this paper, the proposed investigations and studies on root suckers were conducted. The effects of manual factors(grazing) and environmental factors (vegetation factors and soil factors) on root suckers were analysized along the Aqikesu River bank, Ebinur Lake Nature Reserve. The results showed that:At the present stage, the regeneration of local Populus euphratica mainly depends on root sucker and shoot sprout which produced by asexual reproduction, and asexual reproduction by means of root sucker occupied the main position. However, there had no seedling reproduction in all plots.The comparison of the fenced plots with the no-fenced plots indicates that the phenomenon of low number, high die-shoot rate of root suckers of Populus euphratica in this area is mainly caused by overgrazing.Under the situation of no grazing, the root suckers of Populus euphratica generally have three distributional modes including scattered type, medium type and concentrative type. The quantity and growth of root suckers of Populus euphratica in different distributional modes were difference. For the density of root suckers, concentrative type was the highest level, medium type was second, and scattered type was the lowest level. For the height and leaf number of root suckers, concentrative type was higher than scattered type, but medium type was no significantly different from them. As regards to the die-shoot rate, scattered type was the highest level, medium type was second, and concentrative type was the lowest level.The roots with sprout of Populus euphratica generally appeared in the 20 ~ 60cm of soil depth. Among these roots with sprout, the diameter was within the range of 0.5~2.0cm and the length of root node was within the range of 1.0~6.0m accounted for a large proportion. In addition, each root node of Populus euphratica were able to produce ranging from 1 to 6 root suckers, but most of root nodes only produce one root sucker. Comparison for charactertics of root with sprout of Populus euphratica among the three distributional modes showed that, compared with scattered type, concentrative type and medium type's depth distribution of roots with sprout were shallower, length of root node were shorter, and producing capacity of root suckers per root node were more. The linear regression analysis indicated that, under the situation of no grazing, the soil water content, the soil total salt content and the vegetation coverage were the most significant environmental factors effecting root suckers of Populus euphratica.