8种木本植物木质部栓塞变化与生理生态指标关系的研究 Ⅰ.与植物木质部水势的关系  

Relations between Xylem Embolisms and Physiological Indexes in Eight Woody Plants Ⅰ.Relationships with Xylem Water Potentials

作　　者：安锋[1] 张硕新[1] 赵平娟[1] 

机构地区：[1]西北农林科技大学林学院

出　　处：《西北植物学报》2005年第8期1595-1600,共6页Acta Botanica Boreali-Occidentalia Sinica

基　　金：国家自然科学基金(30170766);教育部资助优秀青年教师基金

摘　　要：以自然状况下生长良好的耐旱树种刺槐(RobiniapseudoacaciaL.)、元宝枫(AcertruncatumBge.)、沙棘(HippophaerhamnoidesL.)、白榆(UlmuspumilaL.)、油松(PinustabulaeformisCarr.)、白皮松(PinusbungeanaZucc.exEndl.)及中生树种女贞(LigustrumlucidumAit.)、柳树(SalixmatsudanaKoidz.f.pendulaSchneid.)为研究对象,用压力室法测定木质部水势,用冲洗法测定木质部栓塞程度,研究不同生长季节木质部栓塞与水势间的关系.结果表明:针叶树油松、白皮松在各季节水势均较高,水势变化幅度较小,木质部不易发生栓塞,这与其木质部由管胞构成,对木质部栓塞不敏感,在干旱时采用高水势延迟脱水的耐旱策略有关.阔叶树刺槐、元宝枫、沙棘、白榆、女贞和柳树的木质部栓塞现象是其在每天正常生长过程中不可避免的“平常事件”,是它们适应干旱的一种方式.它们的木质部栓塞程度与水势表现出了相反的变化趋势,即同一树种在同一季节内水势值越低,木质部栓塞程度越大,但在不同树种及同一树种的不同季节不存在这种关系.由此可见,植物木质部栓塞对水势的敏感程度(即木质部栓塞脆弱性)主要由树种的木质部结构决定,同时受到树种特性、树木生长发育时期、外界环境因子的影响,木质部栓塞的脆弱性也具有季节变化特征.With drought-tolerant Robinia pseudoacacia L., Acer truncatum Bge., Hippophae rhamnoides L., Ulmus pumila L., Pinus tabulaeformis Carr., and Pinus bungeana Zucc.ex Endl. and mesophilous Ligustrum lucidum Ait. and Salix matsudana Koidz.f.pendula Schneid. pendula Schneid. , which grow well under natural circumstances, used as the subject materials, the relations between xylem embolisms and water potential in different growing seasons were studied by adopting the“pressure chamber method”to measure the xylem water potentials and the“water-flushing method”to measure the embolisms. The results showed that Pinus tabulaeformis and Pinus bungeana presented higher and slightly-varying xylem water potentials in all the seasons and did not easily suffered embolism in their xylems, which was associated with the insensitivity of the tracheid composition of their xylems to xylem embolism, and the drought-tolerating strategy of making use of high potentials to postpone dehydration occurrence. Robinia pseudoacacia, Acer truncatum, Hippophae rhamnoides, Ulmus pumila, Ligustrum lucidum and Salix matsudana f. pendula could not avoid embolism in their daily growth as if it were“a regular event”and thus they used it as one way to adapt to drought. Their xylem embolisms appeared to vary in an inverse manner as their water potentials, i.e. the lower in one season the water potential of one species was, the severer the embolism were, but same or different tree species in different seasons did not show this relation. Accordingly, the sensitivity of xylem embolism to water potentials （xylem-embolism vulnerability） mainly depended on the xylem structures as well the characteristics, growth stages, environmental factors of tree species, and the xylem embolism vulnerability showed a seasonal varying pattern.

关 键 词：木质部栓塞 水势 栓塞脆弱性 

分 类 号：Q915.79[天文地球—古生物学与地层学]