5个品种橡胶树木质部栓塞及其解剖结构的比较研究

摘要

Maintaining an intact water column within the vascular system is vital to the water supply and vigorous growth of a plant.However, plant xylems are easily to be embolized when they are subjected to stresses such as water deficit and mechanical injury.The objective of this research is to investigate the relationships between xylem embolism vulnerability, embolism refilling ability, vessel anatomy and drought resistance of different rubber tree clones.GT1, Reyan7-33-97, PR107, Renken525, Reken523, which demonstrated diverse growth performances and drought resistances were selected as the plant materials.Embolism vulnerability curves, refilling abilities of embolized xylem from 2.5 MPa pressure collar inducements and xylem anatomies of the five clones were examined.The results indicated that the five clones were all relatively vulnerable to xylem cavitation and also easily to be refilled when the stresses were released.However, there were some divergences between clones, which could be interpreted by their xylem anatomies.Although some correlations could be found between xylem embolism traits and drought resistance of the rubber clones, more elaborative work should be conducted with the simultaneous involvement of cavitation occurrence, embolism refilling ability, stomatal regulation and drought resistance strategy of the rubber tree clones.%维持维管系统水分传输的连续性对于植物的正常水分供给和生长非常重要,然而在水分胁迫、机械损伤等诱因下,植物木质部很容易发生栓塞现象.为比较不同品种橡胶树的木质部栓塞特性及其与木质部结构和抗旱性等之间的关系,选取具有不同抗旱性和生长表现的GT1、热研7-33-97、PR107、热垦525和热垦523为研究对象,绘制了它们1年生枝条的木质部栓塞脆弱曲线,观测了它们对2.5 MPa人为诱导栓塞的恢复能力,探讨了它们木质部栓塞特性与导管直径等之间的关系.结果表明,5个品种的木质部均易发生栓塞,同时,发生栓塞后的木质部导管也容易恢复.然而,各品种发生50%木质部栓塞的水势阈值差异较大,并与木质部导管直径相关联.木质部栓塞特性与不同橡胶树品种的抗旱性可能存在一定的关系,但需将木质部栓塞的脆弱性、恢复能力与各品种的气孔运动、抗旱策略等联系起来做进一步的研究.