Qiman Yunus, Muhtar Zari, Tayer Ahmat
College of Forestry and Horticulture, Xinjiang Agricultural University, Urumqi 830052, China.
Ying Yong Sheng Tai Xue Bao. 2011 Jul;22(7):1789-95.
Taking one-year old Elaeagnus oxycarpa seedlings as test matenals, this paper studied their root activity and leaf cell membrane permeability, relative water content, photosynthetic pigment contents, and photosynthetic parameters at different soil relative moisture contents under natural drought condition. When the soil relative moisture content decreased from 70% (CK) to 40%, the E. oxycarpa seedlings root activity and net photosynthetic rate increased gradually and reached their maximum (1178 microg x g(-1) x h(-1) and 21.9 micromol x m(-2) x s(-1), respectively), photosynthetic pigment contents increased stably, transpiration rate and water use efficiency did not show any significant difference, and cell membrane permeability kept at a low level. When the soil relative moisture content decreased from 40% to 20%, the leaf relative water content was still higher than 50% , cell membrane permeability maintained at a low level, root activity and photosynthetic pigment contents remained high, and other photosynthesis parameters decreased slowly. When the soil relative moisture content decreased from 10% to 5%, the cell membrane permeability increased acutely, but the leaf relative water content, total chlorophyll content, all photosynthesis parameters, and root activity had a significant decrease. The water use efficiency reached the peak when the soil relative moisture content was 10%. To sum up, the optimal soil relative moisture content for E. oxycarpa seedlings should be 40% -50% , and the permanent wilting coefficient of the seedlings was 4.3% (soil relative moisture content).
以1年生沙枣实生苗为试验材料，研究了自然干旱条件下不同土壤相对含水量时沙枣实生苗的根系活力、叶片细胞膜透性、相对含水量、光合色素含量及光合参数。当土壤相对含水量从70%（对照）降至40%时，沙枣实生苗根系活力和净光合速率逐渐升高并达到最大值（分别为1178μg·g-1·h-1和21.9μmol·m-2·s-1），光合色素含量稳定增加，蒸腾速率和水分利用效率无显著差异，细胞膜透性维持在较低水平。当土壤相对含水量从40%降至20%时，叶片相对含水量仍高于50%，细胞膜透性维持在较低水平，根系活力和光合色素含量仍较高，其他光合参数缓慢下降。当土壤相对含水量从10%降至5%时，细胞膜透性急剧增加，而叶片相对含水量、叶绿素总量、各项光合参数及根系活力均显著下降。土壤相对含水量为10%时水分利用效率达到峰值。综上所述，沙枣实生苗适宜的土壤相对含水量应为40% - 50%，其永久萎蔫系数为4.3%（土壤相对含水量）。
