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为提高造林成活率,促进苗木生长,以拉萨河谷地区5种主要乡土造林树种(藏川杨、银白杨、细叶红柳、左旋柳和江孜沙棘)为研究对象,选取2—3年生的苗木进行晾根处理(晾晒时间为0h、2h、4h、6h及8h),晾晒后移栽,测定分析移栽成活苗木叶片脯氨酸(Pro)和丙二醛(MDA)含量的变化。结果表明:5个树种苗木叶片的脯氨酸和丙二醛含量均随晾晒时间的延长而增加,但变化幅度和进程不同。其中,藏川杨晾晒4h的增幅达最大,脯氨酸和丙二醛含量分别增加85.18%和43.10%;银白杨、细叶红柳和左旋柳晾晒6h后增幅均达最大,分别增加53.74%和67.57%,68.5%和297.04%,205.18%和43.62%;江孜沙棘晾晒8h后增幅达最大,分别增加70.93%和39.38%。5种树种裸根晾晒的极限时间分别为藏川杨4h,银白杨、细叶红柳和左旋柳6h,江孜沙棘8h,一定程度上反映出各树种的抗旱性。
In order to increase the survival rate of afforestation and promote the growth of nursery stock, 5 kinds of main afforestation species (Tibetan, Populus tomentosa, Salix millet, Ligustrum lucidum and Gyangze seabuckthorn) in the Lhasa River Valley were selected as the research object, The rooting time was 0h, 2h, 4h, 6h and 8h respectively. After drying, transplanting was carried out. The content of proline (Pro) and malondialdehyde (MDA) in leaves of transplanted live seedlings were measured. The results showed that the contents of proline and malondialdehyde in seedlings of five tree species increased with the prolongation of drying time, but the variation range and process were different. Among them, the average growth rate of Populus davidiana reached 4 hours after drying, and the contents of proline and malondialdehyde increased by 85.18% and 43.10% respectively; the growth of Populus tomentosa, 67.57%, 68.5% and 297.04%, 205.18% and 43.62%, respectively. The growth of seabuckthorn reached the maximum after drying for 8h, increasing by 70.93% and 39.38% respectively. The maximum time for drying bare roots of the four species were 4 h, 4 d, 5 h, 6 h and 6 h, respectively, reflecting the drought resistance of each species.