河套平原沙漠区3种乡土树种人工栽培后的生态适应性

Ecological Adaptability of Three Native Tree Species after Artificial Cultivation in Desert Area of Hetao Plain

乌兰布和沙漠东北段的防护林是保护东部河套平原农业生产的重要生态屏障,由于对人工造林研究缺乏重视,许多防护林体系中的林分有一定的衰退趋势。研究乡土树种人工栽培后的生态适应性,是指导人工防护林建设和可持续经营的重要举措。为了深入探究乌兰布和沙漠乡土树种人工栽培后的生态适应性,本文以3种乡土树种沙冬青(Ammopiptathus mongolicus)、霸王(Zygophyllum xanthoxylon)和蒙古扁桃(Prunus mongolica)为研究对象,通过测定功能性叶片表皮形态、解剖结构、生理指标,结合当地气象数据,阐释3种植物对沙漠环境的适应机制。结果表明:3种植物分别以不同方式适应沙漠环境。沙冬青通过增大叶面积来增加受光面积、提高光合效率,利用密集的表皮毛和发达的角质层强化叶片机械防御能力,降低强光灼伤及水分蒸腾,维持细胞水分平衡,从而降低细胞膜脂过氧化。蒙古扁桃叶片簇生,通过增加叶片数量增加受光面积、提高光合效率,通过卷曲叶片躲避强光灼伤,通过特化气孔位置(将气孔全部分布于叶片下表面),利用发达的维管束、丰富的黏液细胞和晶体结构来降低水分蒸腾,维持细胞水分平衡,从而降低细胞膜脂过氧化。霸王叶片呈圆柱状条形结构,通过降低风阻,降低叶片遭受风沙流危害的概率,通过生理代谢调节提高叶片抗氧化物酶活性和渗透调节物质含量,维持细胞水分和活性氧代谢平衡。这些发现揭示了3种植物在应对荒漠环境时所采取的不同的适应策略,为乌兰布和沙漠东北部乡土树种的引种驯化提供了新思路。

The establishment of shelter forests in the northeastern region of Ulan Buh Desert is a crucial ecological barrier to protect agricultural productivity within the eastern Hetao Plain.However,the lack of attention towards scientific research on artificial afforestation has resulted in a decline tendency in many shelter forest systems.The investigation of ecological adaptability of indigenous tree species after artificial cultivation was a crucial approach to guide the establishment and sustainable management of plantations.In order to further investigate the ecological adaptability of native tree species in Ulan Buh Desert after artificial cultivation,three native tree species:Ammopiptathus mongolicus,Zygophyllum xanthoxylon and Prunus mongolica were used as materials.By measuring the epidermal morphology,anatomical structure,and physiological indices of functional leaves,in conjunction with local meteorological data,the adaptive mechanisms of these plants to arid desert environments were clarified.The results showed that each of three plants exhibited distinct adaptations to arid desert environment in different ways.A.mongolicus enhanced light exposure and photosynthetic efficiency by augmenting leaf area,strengthened leaf mechanical defenses through dense epidermal hairs and well-developed cuticle,reduced light-induced damage and water transpiration,and maintained cellular water balance to minimize lipid peroxidation.The leaves of P.mongolica were clustered,by increasing number of leaves,the light receiving area was increased and the photosynthetic efficiency was improved,and by curling the leaves to avoid strong light burns,the water transpiration was reduced and the cell water balance was maintained by specializing the stomatal position(all the stomata were distributed on the lower surface of the leaves),developed vascular bundles and rich mucous cells and crystal structures,and reduced cell membrane lipid peroxidation.The leaves of Z.xanthoxylon showed a cylindrical strip structure.By reducing the wind resistance,the probability of wind-sand flow damage to the leaves was reduced.The antioxidant enzyme activity and osmotic adjustment substance content in leaves was enhanced by physiological metabolic regulation,and the balance of cell water and reactive oxygen species metabolism was maintained.These findings suggested the different adaptation strategies adopted by the three plants in response to the desert environment,and provided the new ideas for introduction and domestication of native tree species in the northeastern Ulan Buh Desert.