不同类型喀斯特植物的荧光特征及抗旱性比较

Characteristics of chlorophyll fluorescence and comparison of drought resistance among different species of karst plants

关键词:  喀斯特  叶绿素荧光  水分胁迫  聚乙二醇(PEG)

Key words:  karst  chlorophyll fluorescence  water stress  polyethylene glycol(PEG)

摘要:

利用叶绿素荧光技术观测了五个不同类型的喀斯特植物翅荚香槐、大盔凤仙、红背叶、牛耳朵和青冈栎在不同作用光强下的光能利用特征,并且对这五种类型植物在PEG诱导水分胁迫下的抗旱性作了比较。结果表明,随着作用光强的增加,这五种植物的光化学反应能力(qP)逐渐降低,非光化学耗散作用(NPQ)明显增加,同时PSⅡ有效光化学效率(Fv'/Fm')随之下降,导致PSⅡ电子传递量子效率(ΦPSⅡ)也明显下降,但在相同作用光强下这五个类型植物的荧光特征无明显差异。在PEG诱导水分胁迫的实验中,牛耳朵、青冈栎在PEG处理后Fv/Fm变化不明显,而红背叶Fv/Fm值下降程度最大,其次为翅荚香槐、大盔凤仙。由此推测,牛耳朵和青冈栎的耐干旱能力最强,红背叶抗旱能力最弱,翅荚香槐、大盔凤仙居中。

Abstract:

Under different actinic light intensities,the characteristics of light energy using were observed in five species of karst plants by using technique of chlorophyll fluorescence,and their drought resistance was compared under water stress induced by PEG. The five karst plants are Cladrastis platycarpa,Impatiens macrovexilla,Alchornea trewioides,Chirita eburnea and Quercus glauca. The results showed that qP decreased gradually and NPQ increased evidently in these plants with the increase of actinic light intensity. Simultaneously,Fv'/Fm' and ΦPSⅡ declined significantly. However,there was no evident difference in fluorescence characteristics between these plants under the same actinic light. The Fv/Fm of Chirita eburnea and Quercus glauca changed insignificantly under the water stress induced by PEG, and the Fv/Fm decreased moderately in Cladrastis platycarpa and Impatiens macrovexilla,but the value decreased most evidently in Alchornea trewioides. Thus,it was deduced that Chirita eburnea and Quercus glauca are the strongest in drought resistance,Alchornea trewioides is the lowest,Cladrastis platycarpa and Impatiens macrovexilla are in the middle.