以西北农林科技大学校园内生长良好的耐旱树种刺槐(R obin ia p seud oacacia L.)、元宝枫(A certrunca tum Bge.)、沙棘(H ipp ophae rham noid es L.)、白榆(U lm us pum ila L.)、油松(P inus tabu laef orm is C arr.)、白皮松(P in...以西北农林科技大学校园内生长良好的耐旱树种刺槐(R obin ia p seud oacacia L.)、元宝枫(A certrunca tum Bge.)、沙棘(H ipp ophae rham noid es L.)、白榆(U lm us pum ila L.)、油松(P inus tabu laef orm is C arr.)、白皮松(P inus bung eana Zucc.ex End l.)及中生树种女贞(L igustrum lucidum A it.)和柳树(S a lix m a tsud ana K o idz.f.p endu la Schne id)为研究对象,用压力套在2.5 M Pa下诱导1年生枝条发生木质部栓塞,研究自然条件下木质部栓塞的恢复特性,探讨木质部栓塞恢复特性与PV曲线水分参数间的关系。结果表明,木质部栓塞恢复的快慢,与其小枝的木质部栓塞脆弱性顺序基本一致;栓塞的发生和恢复与树木木质部的结构密切相关。植物木质部栓塞的发生、恢复,与植物耐旱性一样受多种因素控制,虽然与PV曲线水分参数有一定关系,但任何单一水分参数的排序,均与木质部栓塞的脆弱性和恢复速率不完全一致。木质部水势和树木不同部位间的水势梯度是影响木质部栓塞发生和恢复的最主要因素,蒸腾作用、气孔关闭及植物的渗透调节等可能也与木质部栓塞的恢复有关。展开更多
Water relations of Alhagi sparsifolia Shap. at the transition zone between oases and sandy desert were studied in the southern fringe of Taklamakan Desert. Results showed that A. sparsifolia maintained the positive tu...Water relations of Alhagi sparsifolia Shap. at the transition zone between oases and sandy desert were studied in the southern fringe of Taklamakan Desert. Results showed that A. sparsifolia maintained the positive turgor during the summer. The steady high predawn water potential (psi(P)) indicated A. sparsifolia had sufficient hydration and water supply in growing season. In July, water deficit caused by drought stress had no effect on the transpiration of A. sparsifolia. Therefore, drought stress is not a main factor affecting the survival of plants. The physiological adaptation to drought of A. sparsifolia was shown mainly at the leaf level by significant difference (DeltaII) and relative water content (RWC) between the osmotic pressure at full turgor and at turgor loss, by occurring of osmotic adjustment, by high percentage of dry mass-related water content ( WCsat), by RWC at turgor loss point ( RWCp) in stable level and low RWC of the saturated symplast (RWCsym). However, the morphological features of transpiring surface reduction and deep root system seem to be the main way for the plant to adapt to the extreme drought environment. Result also suggests that one time of irregular irrigation in summer will not be helpful to recover water status of A. sparsifolia in location where the water table is very low.展开更多
文摘以西北农林科技大学校园内生长良好的耐旱树种刺槐(R obin ia p seud oacacia L.)、元宝枫(A certrunca tum Bge.)、沙棘(H ipp ophae rham noid es L.)、白榆(U lm us pum ila L.)、油松(P inus tabu laef orm is C arr.)、白皮松(P inus bung eana Zucc.ex End l.)及中生树种女贞(L igustrum lucidum A it.)和柳树(S a lix m a tsud ana K o idz.f.p endu la Schne id)为研究对象,用压力套在2.5 M Pa下诱导1年生枝条发生木质部栓塞,研究自然条件下木质部栓塞的恢复特性,探讨木质部栓塞恢复特性与PV曲线水分参数间的关系。结果表明,木质部栓塞恢复的快慢,与其小枝的木质部栓塞脆弱性顺序基本一致;栓塞的发生和恢复与树木木质部的结构密切相关。植物木质部栓塞的发生、恢复,与植物耐旱性一样受多种因素控制,虽然与PV曲线水分参数有一定关系,但任何单一水分参数的排序,均与木质部栓塞的脆弱性和恢复速率不完全一致。木质部水势和树木不同部位间的水势梯度是影响木质部栓塞发生和恢复的最主要因素,蒸腾作用、气孔关闭及植物的渗透调节等可能也与木质部栓塞的恢复有关。
文摘Water relations of Alhagi sparsifolia Shap. at the transition zone between oases and sandy desert were studied in the southern fringe of Taklamakan Desert. Results showed that A. sparsifolia maintained the positive turgor during the summer. The steady high predawn water potential (psi(P)) indicated A. sparsifolia had sufficient hydration and water supply in growing season. In July, water deficit caused by drought stress had no effect on the transpiration of A. sparsifolia. Therefore, drought stress is not a main factor affecting the survival of plants. The physiological adaptation to drought of A. sparsifolia was shown mainly at the leaf level by significant difference (DeltaII) and relative water content (RWC) between the osmotic pressure at full turgor and at turgor loss, by occurring of osmotic adjustment, by high percentage of dry mass-related water content ( WCsat), by RWC at turgor loss point ( RWCp) in stable level and low RWC of the saturated symplast (RWCsym). However, the morphological features of transpiring surface reduction and deep root system seem to be the main way for the plant to adapt to the extreme drought environment. Result also suggests that one time of irregular irrigation in summer will not be helpful to recover water status of A. sparsifolia in location where the water table is very low.
