铝胁迫对常绿杨生长及叶肉细胞超微结构的影响

Growth Characteristics and Leaf Ultrastructures of Evergreen Poplar Clone Under Aluminum Stress

【目的】对酸性条件下铝在常绿杨‘A-61/186’体内积累和分布的规律以及铝胁迫下叶片超微结构与生长生理指标的响应变化进行初步研究,以揭示常绿杨对酸性土壤铝胁迫的响应机制,从而对常绿杨在亚热带地区的推广提供理论依据。【方法】以常绿杨‘A-61/186’为试验材料,在水培溶液中进行铝胁迫试验,对铝胁迫下‘A-61/186’杨的生长量及生物量、植株各组织中的铝含量、叶片叶绿素荧光指标进行测定,并利用透射电镜对叶肉细胞超微结构做系统研究。【结果】酸铝胁迫对常绿杨‘A-61/186’生长状况产生影响,根、茎、叶各组织生长量及生物量均显著下降,生物量分配结构上表现出铝对‘A-61/186’地下部分的影响大于地上;铝胁迫下‘A-61/186’根系较茎、叶组织积累更大量的铝。铝胁迫下‘A-61/186’叶绿素荧光参数显示出叶片通过非光化学的途径将过多的光能进行耗散,因而可降低植物的光合效率,影响生长量和生物量,叶肉细胞超微结构损伤程度的变化与生长量及叶绿素荧光参数的变化相一致,说明铝胁迫下‘A-61/186’生长量和生物量的降低与铝对光合系统的直接损伤有关。【结论】从常绿杨‘A-61/186’体内铝含量及初始生长受抑制的铝浓度来看,相比喜酸性树种茶树、龙眼、桉树等,‘A-61/186’对铝胁迫更为敏感,在酸性富铝化土壤上种植要采用一定的铝毒害防治措施。

【Objective】Poplar are a sort of plants that are usually for planting in neutral to partially alkaline soil,however the fast development of new varieties for cultivation has expanded its planting range. A-61 /186（Populus ×euramericana cv. A-61 /186） is a evergreen poplar clone that is suitable for low-latitude tropical and subtropical areas,and it has been introduced to Fujian Province of China and presents evergreen characteristics. However,when it is planted in tropical or subtropical areas,it faces a prominent issue of acidic soil in which aluminum is rich,which can bring adverse effects. In this study, the patterns of aluminum accumulation and distribution in the body, the response of leaf ultrastructure and the physiological indexes under the condition of acid aluminum were investigated. The study aims to reveal mechanism of the macro and micro structure of the evergreen Poplar adapting to aluminum stress,thus providing a theoretical basis for the widespread of the evergreen poplar in subtropical regions. 【Method 】 In this study,and the evergreen poplar clone ‘A-61 /186’was grown in hydroponic solution for aluminum stress experiment,and the effects of aluminum stress on the growth,biomass,chlorophyll fluorescence indicator and leaf ultrastructures by using transmission electron microscopy（TEM） were studied systematically. 【Result】The results showed that the acidic aluminum stress had an impact on the growth of the evergreen poplar; the acidic aluminum stress significantly decreased the growth of roots,stems,and leaves as well as biomass of the evergreen poplar,and it had a much greater impact on the underground part than the above ground part. In addition,aluminum was accumulated more readily in the roots than in the stems and leaf tissues. Chlorophyll fluorescence showed that the absorbed light was non-photochemical and dissipated under aluminum stress,which reduced its photosynthetic efficiency,thereby affecting the growth and biomass. Furthermore,the degree ofinjury to the mesophyll cell ultrastructure is consistent with the growth and chlorophyll fluorescence parameters,which indicated that the effects of aluminum stress on the evergreen poplar clone’s growth and biomass were directly related to the damage to the photosynthetic system.【Conclusion】With regards to the aluminum content in the evergreen poplar clone and the aluminum concentration that inhibited growth,the evergreen poplar clone was more sensitive than acidic species,such as tea,longan,and eucalyptus. Therefore,when planting this evergreen poplar clone in acidic soil,aluminum toxicity should be considered.