Reproductive Characteristics Of Populus Euphratica Oliv. In Ejina Oasis

In this paper, the general regeneration conditions, the characteristics of seed germination and root suckers of Populus euphratica Oliv. were studied. The result shows that these years Populus euphratica Oliv. depended on asexual reproduction to sustain, and root suckers constitute a large part of the whole saplings while no seedling has been found. The middle-aged forests can produce the most root suckers in all types of forests of Populus euphratica Oliv. Populus euphratica Oliv. has a less powerfully asexual reproductive capability in the community where there are more trees. Salinities and water stress has negative effects on the germination of seeds. Germination rate of seeds growing under high concentration of salinity solution or low water level decreases significantly. Seeds growing in soil collected under trees of Populus euphratica Oliv. have a lower germination rate than those growing in sand and silt when the content of water exceeds 20%. In the irrigated forest gap, both the density of root suckers and the number of adventitious buds per root are higher than that in habitats of sand and forest. The suitable layer for the roots to sprout adventitious buds in sand, forest and irrigated forest gap are in 30cm, and roots growing under 30cm in the soil can't sprout adventitious buds. In Ejina oasis, Populus euphratica Oliv. assigns more energy to sexual production while the energy assigned to asexual reproduction is comparatively less. Populus euphratica Oliv. produces a large number of seeds with vigor every year, however, as there is no suitable habitat for seeds to germinate, the reproductive strategies of Populus euphratica Oliv. failed, and that is the main reason why the population of Populus euphratica Oliv. regenerates difficultly.