【作者】 衣学慧；

【导师】 赵忠；

【作者基本信息】 西北农林科技大学 ， 森林培育， 2008， 硕士

【摘要】 柠条锦鸡儿(Caragana korshinskii)、沙木蓼(Atraphaxis bracteata)、蒙古岩黄芪(Hedysarum mongolicum)、细枝岩黄芪(Hedysarum scoparium)、互叶醉鱼草(Buddlejaalternifolia)、四翅滨藜(Atriplex canescens)等6种灌木在沙地有着较高的利用价值。为在干旱条件下造林学研究提供理论依据,以其1年生苗为材料,进行了3个土壤水分条件(适宜水分、中度干旱、重度干旱)下的长时期盆栽控水试验。通过测定生物量、叶片水分状况、细胞质膜透性、有机和无机渗透调节物质(脯氨酸、甜菜碱、可溶性糖、可溶性蛋白质、K~+、Na~+、Cl~-)含量等,分析了6种灌木的抗旱适应性。试验结果表明:(1)在6种灌木当中,四翅滨藜和醉鱼草的总鲜重、干物质积累量在适宜水分条件下都显著高于其它树种。二者即使在中度干旱下,四翅滨藜甚至在重度干旱下,总鲜重、干物质积累量也都比较大。但与适宜水分条件下相比,6种灌木的总鲜重、干物质积累量在中度和重度干旱下都下降。生理方面也有一致的响应:黎明前叶水势、叶片相对含水量都降低,质膜透性都增大。其中重度干旱的影响大于中度干旱。6种灌木在总鲜重和干物质积累量的降幅、质膜透性的增幅、黎明前叶水势和叶片相对含水量的大小等方面具有差异。毛条、沙木蓼、四翅滨藜抗旱性较强,杨柴、花棒、醉鱼草抗旱性较弱。6种灌木应当说都具有一定的抗旱性,相对都能适应中度干旱。醉鱼草是适应重度干旱较差的树种。(2)除四翅滨藜的根鲜重在水分胁迫下增加外,其余树种的根鲜重如同6种灌木的茎、叶鲜重都在减小。但就降幅而言,水分胁迫对地下部分根系的影响较小,而对地上部分影响较大,尤其叶对干旱最为敏感。在地上部分鲜重比例在水分胁迫下下降的同时,6种灌木的根鲜重比例及根冠比在水分胁迫下都增大,尤其在重度干旱下表现一致。植物根系在水分胁迫下的特征体现植物的御旱性。由根系鲜重比例的大小、根冠比的增幅所反映的6种灌木的御旱性不同于其抗旱性,说明树木的抗旱性是由其耐旱性与御旱性共同决定的。(3)在水分胁迫下,6种灌木均表现出耐旱的渗透调节过程,但在参与物质、累积程度、发生时期、发生的水分胁迫强度类型等方面有所差别。除有机物质外,无机离子也起一定的作用。甜菜碱均参与了6种灌木的渗透调节过程,其它渗透调节物质则有例外。更多还原

【Abstract】 The six shrubs,Caragana korshinskii,Atraphaxis bracteata,Hedysarum mongolicum, Hedysarum scoparium,Buddleja alternifolia,Atriplex canescens,have a higher value for the sand.We researched their drought adaptability under long period water control test（suitable for water,moderate drought,severe drought）by potted cultivate 1-year seedlings,though respectively testing their biomass,leaf water status,cell membrane permeability,organic and inorganic osmotica(proline,betaine,soluble sugar,soluble protein,K⁺,Na⁺,C^1-),the results showed that:1.The total fresh weight（FW） and dry matter accumulation（DMA） of Atriplex canescens and Buddleja alternifolia’ are significantly higher than that of other 4 species under the appropriate water conditions.They both have higher total FW and DMA under the moderate drought condition,and Atriplex canescens is better than the other even under the severe drought condition.But they all decreased of 6 species under the moderate drought and severe drought conditions compared with the suitable for water condition.and the 6 species have the same physiological response with FW and DMA.At pre-dawn,the leaf water potential and leaf water content declined,membrane permeability ascended,and which were more affected under the severe drought condition than under the moderate drought condition.The 6 species were different in extent of decline of total FW and DMA,ascending of membrane permeability and decline of the pre-dawn leaf water potential and leaf water content.They all can resist drought,relatively adapt to moderate drought condition,and Caragana korshinskii, Atraphaxis bracteata and Atriplex canescens were stronger than Hedysarum mongolicum, Hedysarum scoparium and Buddleja alternifolia.Buddleja alternifolia is the last specie among 6 species adapted to plant in the severe drought area.2.Except Atriplex canescens,the root FW of other 5 species increased in drought stress. It’s sameness in the stem FW and leaf FW.For extent,drought stress was less affected underground root than ground root,leaf was the most sensitive to drought stress.With the falling of FW ratio of ground part,however,the FW ratio and root/shoot ratio of 6shrubs were increasing in drought stress,and it’s the same performance under the severe drought condition. The characteristics of plant root reflect its drought adaptability.It’s different drought defence to drought resistance which was reflected by the extent of root FW ratio and root/shoot ratio, which showed that drought resistance was decided by combine of drought defence and drought tolerance.3.In drought stress,6 shrubs represented osmoregulation process of drought tolerance, but their performance were different in joined material,accumulate extent,process period, drought stress strength.Except organic material,inorganic ion also play a role.Betaine joined the whole osmoregulation process,other osmotic adjust materials are exceptions.更多还原