【作者】 田有亮；

【导师】 郭连生；

【作者基本信息】 内蒙古农业大学 ， 水土保持与荒漠化防治， 2005， 博士

【摘要】 本文研究了樟子松(Pinus sylvestris var.mongolica)的主要耐旱生理生态特征在不同地区、不同土壤水分状况和叶水分状况下的变化,进而研究了樟子松对水分胁迫的反应和适应,结果如下: 1 应用 PV 技术对半湿润区、半干旱区和干旱区樟子松耐旱性指标测定研究指出,水饱和总体渗透势(πo)和初始失膨点总体渗透势(πp)随着气候干旱程度增加而增加,与气候湿度指标(Im)呈直线相关,证明了樟子松属于耐旱性可变的树种,渗透调节能力增加是其对干旱气候适应的主要途径。 2 樟子松净光合速率、蒸腾速率和水分利用效率日进程变化与土壤水分状况的关系研究表明,三者的日平均值(y)与土壤含水量(x)、清晨叶水势(x)均呈 y=A+Be-kx,净光合速率日平均值为 0 时对应的土壤含水量(SWCp0)和清晨叶水势可作为树木初始水分胁迫的指标,在同质土壤下可运用 SWCp0评价树种耐旱性,并获得被试树种的耐旱性排序为:侧柏>樟子松>油松>白杄。 3 对樟子松小枝不同脱水状态下吸水特征、光合速率、蒸腾速率等与其叶水势关系的研究指出,重饱和相对含水量(RWCrs)可作为评价树木吸水能力的一个指标。RWCrs 愈小,吸水能力愈弱。RWCrs随叶水势下降而减小,二者关系呈 y=k-ae(-bx)。净光合速率与水势关系呈 y=a+b/(1+e(-Kx)),总光合速率、蒸腾速率、叶绿素荧光猝灭、光化学量子产量和电子传递速率等荧光特征指标与水势关系均呈“S”型曲线。 4 研究指出πp是树木吸水能力变化的初始水势,是树木正常生长必需的蒸腾速率的水势下限,πp小于等于净光合速率水势补偿点,与非光化学猝灭初始下降点水势相近,因此,πp可作为树木正常生长的水势下限。对树木丧失恢复吸水能力的初始水势、总光合作用近于 0 的水势(ψrpc)、蒸腾速率近 0 水势和叶绿素荧光指标值近于 0 的水势比较研究指出,ψrpc可作为树木生命活动的水势下界。ψrpc与πp呈直线相关,具有生长发育期的变化。运用πp和ψrpc可获得树木生长水势阈和树木生命水势阈。研究对于樟子松在干旱、半干旱地区造林和植物与水分关系的研究都有着重要的理论和实践意义。更多还原

【Abstract】 The eco-physiological characteristics of drought endurance of Pinus sylvestris var.mongolica were studied under different climatic regions, soil water and leaf water condition.Furthemore,the response and adaptability of trees to water stress was done.The below showed the results. 1 The parameters of drought endurance of P. sylvestris var. mongolica was measure and studied by PV technology in the subhumid, semiarid and arid regions The results indicated the osmotic potentials at water saturation condition (πo) and at the initial loss turgor(πp) decreased as the climatic drought degree increased,and related linearly with the climatic moisture index(Im).It was proved that the drought endurance of P. sylvetris var. mongolica was varible and the elevation of the osmotic adjust capability was a main way to the adaptation of trees to the drought climatic environment. 2 The relationship between the daily average(y) of the net photosynthetic rate, transpiration rate and water use efficiency tested trees and soil moisture content(x) or morning leaf water potential(x) could be expressed as y=a+be-kx. The soil moisture content(SWCp0)and the leaf water potential when the net photosynthetic rate equal to 0 were the indexs of the initial water stress condition for the growth and development of trees. SWCp0 could be used to evaluate the drought endurance of the tree species under the same soil and the order of the drought endurance of the tested trees was Platycladus orientalis>P. sylvestris var. mongolica>P. tabulaeformis>Picea meyeri. 3 The research on the relationship between the water absorption characteristic of the tested trees and the leaf water potential(ψ) showed that resaturation relative water content (RWCrs) could be a index to evaluate the water absorbing capability of trees. The water absorbing capability of trees was less when RWCrs was less. RWCrs decreased asψdecreased, the relationship between them was y=k-ae(bx).The relationship between the photosynthetic rate and the leaf water potential could be expressed as y=a+b/(1+e(-kx)). The correlative curve between the total photosynthetic rate, transpiration rate, fluorescence characteristic index and water potential was all “S” curve. 4 Based on the critical point of the above correlative curve of tested trees,results indicated πp was the minimal water potential for normal growth and development of trees as πp was the water potential at the initial variation of the absorbing characteristics,the the minimal water potential of the transpiration rate required for normal growth and development of trees,less or equal to the net photosynthetic rate water potential compensation point and approximating to the initial water potential when the quenching of chlorophyll fluorescence decreased with .the leaf water potential decreased. Compared the critical leaf water potential of trees when the total photosynthetic rate,transpiration rate, the chlorlphyll fluorescence parameters were approximating to 0 and the water absorbing capability was losed initially, the critical water potential at the total photosynthetic approximating to 0(ψrpc) could be the minimal water potential for the survival of the tree. Ψrpc related to πp linearly, was the difference in different growth period of trees,used to evaluate the adaptability of trees to the severe water stress. Growth water potential field and life water potential of trees could obtained by πp and Ψrpc. It was important theory and practical significance for the afforestation of the tree under arid and semiarid regions and the research on relationship between plants and water.更多还原