为了解共和地区典型固沙植物的根系分布特征,为该地区人工植被恢复的物种选择提供依据,本文选取当地典型荒漠化防治植物种中间锦鸡儿、柠条锦鸡儿、沙柳、小叶杨、小穗柳和乌柳6种植物,进行根系分布特性研究。采用整株挖掘法获取植物根系样本,使用WinRHIZO Pro 2500a 根系分析系统,计算根系生物量密度、根长密度、比根长、根系消弱系数。所研究的6种植物根系主要集中在0 ~40 cm 深度范围内,根系生物量密度与根长密度沿土层深度波动下降。小穗柳细根比根长显著大于其他植物种,说明其细根根系活性最强,对环境的适应性最好。沙柳与中间锦鸡儿的根系生物量消弱系数显著大于其他植物种,沙柳的根长密度显著大于其他植物有助于增加土壤抗性,具有较强的固土能力。柠条锦鸡儿的生物量密度显著大于其他植物种,获取能量的能力较强。在共和盆地人工植被恢复宜选用适应性较强的小穗柳,或固土能力较强的沙柳与中间锦鸡儿。
[Background] Desertification is one of the most serious environment problems in China, which has resulted in the land degeneration and affected local people life. Local economic development is also hindered by the desertification, and this situation may last for quite a long time. Gonghe Basin, located in Qinghai Province of China, is a typical desertification area. Artificial vegetation restoration, which performs well in desertification area of China, may immobilize moving dunes, control desertification and improve environment. Root is the most important plant organ of obtaining water and nutrients from soil, and also plays a key role in plant growth and metabolism. Study of root system distribution patterns means significant for the selection of suitable afforestation tree species and survival rate enhancement. [Methods] Six typical desertification control plants in local area were selected for this study: Caragana intermedia, Caragana korshinskii, Salix psammophila, Salix microstachya, Populus simonii and Salix cheilophila in six plots separately with area of 20 *20 m2. All the studied plants were grown in 1990s with method of cuttage forestation. Plant height and crown diameter were measured and then type trees were chosen. The root samples of type tree were obtained by whole plant excavating method and scanned by WinRhizo Pro 2500a Root Analysis System. Finally, root biomass density, root length density, specific root length, and root extinction coefficient were calculated and analyzed. The root of studied plants mainly distributes in 2 m diameter circle away from trunk, so we excavated this area to get root samples. [Results] Specific fine root length of S. microstachya (2.74 m/g) was significantly higher than that of other five species (P >0.05), indicating that the fine root activity of S. microstachya was the strongest, and it can be inferred that fine root of S. microstachya adapted best to the environment among all 6 plants. Root biomass extinction coefficients of S. psammophila and C. intermedia (0.982, 0.979) were significantly higher than that of other five species, thus they may function well in increasing soil shear resistance. The root biomass density of C. korshinskii (3.882 kg/m 3) was significantly higher than that of other five plants (P >0.05), the root length density of S. psammophila (372.728 cm/m3) was significantly higher than that of other five plants. Therefore, C. korshinskii presented the strongest ability of obtaining energy. All studied plant roots distributed mainly between 0 - 40 cm depth in soil. Root biomass density and root length density both decreased with depth and distance from trunk center. Root distribution was not affected by soil moisture content in short period. [Conclusions] As a result, it can be seen that in Gonghe Basin of Qinghai Province, S. microstachya with strong adaptability, S. psammophila and C. intermedia with strong reinforcement capability perform best in artificial vegetation recovery.