中文摘要：

以3—4年生柠条、沙柳、沙棘、白沙蒿为研究对象，选取直径1．5—2mm和3～3．5mm2个径级根系，采用TY一8000伺服式强力机测定相同径级的直根段和侧根分支处对于加载速度的响应。研究结果表明：4种植物同径级直根段抗折强度均大于侧根分支处抗折强度，且抗折强度随加载速度增加而增大。最大加载速度与最小加载速度下抗折强度差异性显著。当加载速度为860mm／min和10mm／min，根径1．5—2mm．柠条直根段、侧根分支处的抗折强度分别为63．79Mpa、39．20Mpa和50．76Mpa、27．40Mpa；沙柳分别为25．54Mpa、26．05Mpa和19．22Mpa、14．55Mpa；沙棘分别为9．65Mpa、6．76Mpa和6．17Mpa、4．28Mpa；白沙蒿分别为6．40Mpa、2．67Mpa和4．96Mpa、2．35Mpa。同样，根径3～3．5mm时，柠条直根段、侧根分支处的抗折强度分别为53．42Mpa、33．00Mpa和41．17Mpa、19．38Mpa；沙柳分别为20．03Mpa、16．22Mpa和16．60Mpa、10．60Mpa；沙棘分别为7．76Mpa、3．47Mpa和5．41Mpa、2．27Mpa；白沙蒿分别为5．33Mpa、2．39Mpa和3．26Mpa、1．58Mpa。

英文摘要：

Taking 3 - 4 - year Caragana korshinskii, Salix psammophila, Hippophae rhamnoides and Artemisia blepharolepis as the research objects, choosing two root system with the diameter at 1.5 ~ 2 mm and 3 - 3.5 mm, the responses of straight root and lateral root branch with same diameter to loading speed have been measured by use of TY - 8000 servo - type powerful machine. The results show that for four plants, the flexural strength at straight root is stronger than the one at lateral root branch, and the flexural strength has enlarged with the increasing of loading speed. There is significant difference between the flexural strength at the maximum and the minimum load- ing speed. When loading speed at 860 mm/min and 10 mm/min and root diameter at 1.5 - 2 mm, the flexural strength at straight root and lateral root branch of Caragana korshinskii is 63.79 Mpa, 39.20 Mpa and 50. 76 Mpa, 27.40 Mpa separately, the one of Salix psammophila is 25.54 Mpa, 26.05Mpa and 19.22 Mpa, 14.55 Mpa sepa- rately, the one of Hippophae rhamnoides is 9.65 Mpa, 6. 76 Mpa and 6. 17 Mpa,4.28 Mpa separately, the one of Artemisia blepharolepis is 6.40 Mpa, 2. 67 Mpa and 4. 96 Mpa, 2. 35 Mpa separately. When loading speed at 860 mm/min and 10 mm/min and root diameter at 3 ~ 3.5 mm, the flexural strength at straight root and lateral root branch of Caragana korshinskii is 53.42 Mpa, 33.00 Mpa and 41.17 Mpa, 19.38 Mpa separately, the one of Salix psammophila is 20.03 Mpa, 16.22 Mpa and 16.60 Mpa, 10.60 Mpa separately, the one of Hippophae rhamnoides is 7.76 Mpa, 3.47 Mpa and 5.41 Mpa, 2. 27 Mpa separately, the one of Artemisia blepharolepis is 5.33 Mpa, 2.39 Mpa and 3.2 6Mpa, 1.58 Mpa separately.