Cloning Root System Distribution And Architecture Of Populus Euphratica In Ejina Oasis

Plant population regeneration is of great importance for restoration of degraded ecosystems and preservation of biodiversity in the extreme arid region. The effects of soil environment on the characters and sprouting of propagative root of populus euphratica were investigated to elucidate the development mechanism of adventitious buds and root suckers. It was contributive to ameliorate the regeneration of the degraded riparian forest in the Northwest of China. Based on the investigation on soil profile and rhizotron in middle-aged and mature-aged Populus euphratica forest, the cloning root distribution characteristics, the root architecture, and the relationship between the sucker root and propagative root architecture were analyzed. Results show that:(1) with the increasing of the soil depth, the root length density (RLD) and root surface Area density (SAD) of fine root (d<2mm) present the exponential function.(2) In different depths among0-90cm, the RLD and SAD of the fine root in middle-aged forest were significantly larger than the ones in mature-aged forest (p<0.05). However, in70-90cm (deeper layers) and40-50cm (shallower layers), the RLD and SAD of the middle-sized thick roots (5mm<d<20mm) and the thick roots (20mm<d) in middle-aged forest, were significantly smaller than those in the mature-aged forest (p<0.05).(3) In the middle-aged forests, the root surface area, the root forks, the root fractal dimension, and the average branch angle were chosen as principal components in analyzing the root architecture. But the root volume, the root forks, and the average branch angle were chosen as principal components in mature-aged forest. The principal component analysis on the root order showed that the diameter class among1-2mm significantly influenced the SAD and the root volume.(4) There were no significant difference in the amount of the adventitious buds on cloning roots, the first-ordered lateral roots and branch angle between the two-age forests (p<0.05).(5) It was found that the amount of the adventitious bud on the second-ordered roots were3～4times more than that on the first-ordered roots by comparing the shoot bud on different root orders in the two-age forests.Our result suggested that the fine roots (d<2mm) would significantly affect the clone root architecture of Populus euphratica, and played an important role in the trade-off of Populus euphratica root function. Research Populus seedlings under different environmental conditions and development results show:Populus seedlings at low N, salinity treatments, Populus root configuration parameters changes show that roots to deeper and wider range of diffusion, it Benefit from a wider range of Populus absorb nutrients. High concentrations treatments showed inhibition. P treatment, High concentrations of P induced more Populus fine root biomass. Root configuration parameters:the number of root branching, apical points, branch angle, fractal dimension are showing an increasing trend. P-treatment may promote Populus lateral root development in the horizontal direction, To seek high-quality plaque.