【作者】 贾利强；

【导师】 李吉跃； 郎南军；

【作者基本信息】 北京林业大学 ， 森林培育， 2003， 硕士

【摘要】 金沙江干热河谷气候燥热干旱，土地退化严重，水土流失强烈，生态环境极其恶劣。强烈的水土流失以成为长江上游泥沙的重要来源。为此查明干热河谷地区主要造林树种抗旱的生理生化特征及其影响因素，对干热河谷造林树种的选择具有重要的意义。本实验通过盆栽试验来模拟自然干旱对金沙江干热河谷几种主要造林树种的生理生化影响，以此来探讨参试树种的抗旱机制，并为该地区造林树种的选择提供依据。主要研究成果如下： 1．金沙江干旱季节，坡柳(Dodonaea viscosa)中午出现明显的光合午休现象，非气孔限制因素是造成坡柳光合午休的主要原因。坡柳通过降低净光合速率和提高水分利用效率来适应水分缺乏。清香木(Pistacia weinmannifolia)有较高的光补偿点和光饱合点，属于阳生植物。 2．水分胁迫对六种参试树种的生理生化等指标产生明显的影响。水分胁迫下，六种参试树种叶片的最大荧光效率下降，初始荧光上升，叶绿素含量下降，光合机构受到破坏；脯氨酸和可溶性糖含量明显增加，渗透调节在六种树种的抗旱机制中有重要作用；叶片相对电导率增加、丙二醛含量上升，细胞膜质受到损伤，SOD活性变化不明显，POD活性上升，清除活性氧保持细胞膜的完整性方面，POD酶所起的作用要大于SOD酶。参试树种对水分胁迫有不同的适应机制。 3．利用测试八个生理生化指标，通过隶属函数综合值法对四种参试树种抗旱能力进行了排序。四种树种的抗旱能力从高到低依次排列为坡柳、(清香桂(Sarcococca ruscifolia))、银合欢(Leucaena Leucocephala)、清香木、黄连木(Pistacia chinensis)、山毛豆(Tephrosia caudida)。更多还原

【Abstract】 The climate in Jinsha River Dry-hot valley is hot and dry during drought season,soi) erosion and degradation of land resources are significant problems, Eco-environmental is more serious.The intense soil and water loss has become mainly sediment sources of The upper reaches of Yangtze river.So it is important to investigate for some important silvicullural species character of physiological and biochemical and effect factor about drought-risistance.in order to further well select tree species for afforestation activities of Dry-hot valley,Through simulate arid conditon,we studied several important silvicultural species how to reponse water stress and further discuss them drought-resistance mechnism,and to do that we hope that we can provide scientific basis for tree species selection for afforestation activities in Dry-hot valley. The main results of the study are as follows:1. During the drought period, the plant of Dodonaea viscosa showed signigicant midday depression on sunny days, the main reason is that Nonstomatal limitation resulted in midday depression of D. viscose seedlings.D. viscosa plant adapt to dry-hot season with higher WUE and lower rates of photosynthesis, seedlings of Pistacia chinensis have higher light compensation point and saturation point.2. Water stress remarkably impact on physiological and biochemical indexes’of six experiment spieces.Under water stress,maximum photochemical efficiency( F v / F m) value and chl content decline ,basal rates of chl fluorescence( F 0) value ascend,photosynthetic organ was damaged;content of proline and total soluble sugar markly increase,osmotic adustment play an important role for six species of drought-risistance;leaf relative conductivity rate increase and malondialdehyde content ascend,cell plasmid membrane was destructed,SOD activity hardly change and POD activity ascend,show that POD activity play more important role inquenching activated oxygen than SOD does. Experiment species have different adaptive mechanisms for water stress.3. By studying 8 physiological and biochemical indexs of 6 plant species, applying The comprehensive appraisal index of drought tolerant physiological reaction and adaptability we estimeated and ordinated the drought tolerance of the species comprehensively as follows: Dodonaea viscose, Sarcococca ruscifolia, Leucaena Leucocephala , Pistacia weinmannifolia , Pistacia chinensis Bunge , Tephrosia caudida.更多还原