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土壤水分胁迫对黄土丘陵区3个树种叶片气体交换的影响

Influences of Soil Water Stress to Leaf Gas Exchange of Three Tree Species in Loess Hilly Region

作者: 专业:水土保持与荒漠化防治 导师:张光灿 年度:2010 学位:硕士  院校: 山东农业大学

Keywords

Losses hilly region, soil water stress, leaf stomatal conductance, photosynthesis physiology, chlorophyll fluorescence

        半干旱黄土丘陵区是我国典型的生态脆弱地区,而水分是制约植被恢复与重建的主要因素。本文针对半干旱黄土丘陵区干旱缺水的主要特征,在山西省方山县峪口镇,以山杏(Prunus armeniaca)、沙棘(Hippophae rhamnoides)和油松(Pinus tabulaeformis)3个树种为试验材料,进行盆栽试验设计,运用气体交换和叶绿素荧光监测技术与分析理论,阐明不同树种光合速率、蒸腾速率、水分利用效率等气体交换参数及叶绿素荧光参数在土壤饱和湿度至凋萎湿度内的连续变化过程;揭示不同树种光合特征参数发生显著变化的土壤水分临界点及其变化机制;确定维持不同树种较高光合速率和水分利用效率的土壤水分范围。研究成果对丰富和发展树木光合生理与水分生理研究具有理论价值,对科学指导黄土丘陵区合理树种选择、立地配置和适地适树具有实践价值。主要研究成果如下:(1)植物叶片气体交换参数对土壤水分和光照强度有明显的阈值响应根据光合速率、蒸腾速率、水分利用效率等气体交换参数与土壤水分关系的分析结果,初步确定了3个树种以提高光合生产力与水分利用效率为核心的适宜土壤水分条件、植物水分最大亏缺及适宜的光强范围。①山杏、沙棘和油松生长适宜的土壤水分范围分别为:36.39%~80.90%、38.49%~82.86%、35.72%~80.83%;土壤水分最大亏缺分别为:28.33%、30.00%、27.61%;光照强度范围分别为:600~1400μmol·m-2·s-1、500~1600μmol·m-2·s-1、400~1600μmol·m-2·s-1。3个树种在轻度水分胁迫下能获得较高的光合速率和水分利用效率,有较高的光合生产力。②3个树种的AQY、Rd和LCP对土壤水分具有明显的阈值响应。植物对弱光的利用能力由高到低的顺序为:山杏、沙棘、油松;对光合产物的消耗由多到少的顺序为:沙棘、山杏、油松;耐荫性由高到低的顺序为:沙棘、油松、山杏。(2)CO2浓度和土壤水分胁迫对植物叶片气体交换参数的影响①研究在不同水分条件下植物叶片气体交换参数对CO2浓度水平的响应,有助于阐明植物对CO2浓度和水分条件的响应特性。各CO2浓度下,Pn在RWC为65.71%左右时维持较高值,高于或低于此值,Pn逐渐降低。在各水分条件下,随着CO2浓度的升高,Pn没有出现下降的现象。重度水分胁迫时,随着CO2的增加,Pn、Tr和Gs没有发生明显的变化,均维持在很低的水平,说明严重的水分胁迫使植物气孔基本已经关闭,严重影响了植物的正常生理活动。②3个树种的CE、Γ和Rp对土壤水分的变化具有明显的阈值响应。山杏和沙棘在重度水分胁迫下, CE和Rp均达到最小值,随着水分胁迫的缓解,其值逐渐增大。Г对土壤水分的响应过程与CE呈现相反的规律,轻度水分胁迫下达到最低值,土壤水分增加或减少都会使Г增加。(3)叶绿素荧光参数对土壤水分胁迫的影响在土壤干旱胁迫下,3个树种的叶绿素荧光参数表现为Fo上升,Fm、Fv/Fm等值下降。而各树种的qP和NPQ则表出现不同的变化规律。山杏的qP随着土壤水分胁迫程度的加剧,呈逐渐增大的趋势,而沙棘则表现出与山杏相反的趋势;山杏和油松的NPQ在轻度水分胁迫下最大,其后有所减小。而沙棘的NPQ则在CK时最大,在轻度水分胁迫时达到最小值,其后随着水分胁迫的加剧又逐渐增大。
    Semi-arid loess hilly region, in which water is the main factor of restricting vegetation restoration and plant restoration and reconstruction, is the typical ecological fragile area in our contry. Aiming at the main character of drought and water shortage in this region, pot experiment of Prunus armeniaca, Hippophae rhamnoides and Pinus tabulaeformis were arranged in Yukou, Fangshan, Shanxi. Based on the monitoring technology and analysis theory of gas exchange and chlorophyll fluorescence, processes and characteristics of continuous variation of different tree species’leaf gas exchange parameters such as photosynthetic rate, transpiration rate and water use efficiency and chlorophyll fluorescence parameters in the range from soil saturated humidity to wilting humidity were elucidated, soil water critical points at which photosynthetic parameters change significantly and its changing machanism were revealed, soil water ranges maintaining high photosynthetic rate and water use efficiency of different tree species were determined. The results of this research can have theoretical value to enrich and develop photosynthetic physiology and water physiology of tree, and have practical value to scientifically direct tree species choice, site allocation and favored trees for suitable land in loess hilly region. The main results are as followes:(1) Plant leaf gas exchange parameters have clear threshold value responses to soil water and light intensity. According to the relationships between phtosynthetic rate and soil water, transpiration rate and soil water, water use efficiency and soil water, suitable soil water range, maximum water deficit and suitable light intensity range of keeping high photosynthetic productivity and water use efficiency of 3 tree species were preliminary determined.①Suitable soil water ranges for Prunus armeniaca, Hippophae rhamnoides and Pinus tabulaeformis growing were respectively 36.39%~80.90%, 38.49%~82.86% and 35.72%~80.83% ; light intensity were repectively 600~1400μmol·m-2·s-1, 500~1600μmol·m-2·s-1 and 400~1600μmol·m-2·s-1. Under mild water stress, the 3 tree species can keep high photosynthetic rate, water use efficiency and photosynthetic productivity.②AQY、Rd and LCP of the 3 tree species had clear threshold value responses to soil water. The ability of using weak light of Prunus armeniaca was bigger than that of Hippophae rhamnoides, and the ability of Hippophae rhamnoides was bigger than that of Pinus tabulaeformis.The consumption of photosynthetic product of Hippophae rhamnoides was more than that of Prunus armeniaca , and the consumption of Prunus armeniaca was more than that of Pinus tabulaeformis. The shade tolerance of Hippophae rhamnoides was larger than that of Pinus tabulaeformis, and the tolerance of Pinus tabulaeformis was larger than that of Hippophae rhamnoides.(2) Influences of CO2 concentration and soil water stress to plant leaf gas exchange parameters.①The research of responses of plant leaf gas exchange parameters to CO2 concentration in different water conditions was benefit to elucidate response characteristics of plant to CO2 concentration and soil water. In each CO2 concentration, Pn was largest when the RWC was 65.71%. And in each soil water condition, Pn did not decrease when CO2 concentration increased. Under heavy water stress, Pn、Tr and Gs all kept low level and did not change significantly, which showed that leaf stomata nearly closed in heavy water stress condition and plant normal physiological activities were influenced badly.②CE、Γand Rp of the 3 tree species had clear threshold value responses to soil water. Under heavy water stess, CE and Rp of Prunus armeniaca and Hippophae rhamnoides were both at their lowest values, and both of their values incressed when water stress was alleviated. Response process ofГto soil water was opposite to that of CE to soil water.Гreached its lowest value and it increased when soil water increased or decreased.(3) Influences of chlorophyll fluorescence parameters to soil waterWhen the experimental trees were in soil water stress conditions, their Fo increased, Fm and Fv/Fmdecreased. But the changing characteristics of qP and NPQ were different. qP of Prunus armeniaca increased as degree of soil water stress aggravated while that of Hippophae rhamnoides showed the opposite trend; NPQ of Prunus armeniaca and Pinus tabulaeformis reached their highest level under mild water stress. To the contrary, NPQ of Hippophae rhamnoides had the biggest value in the CK condition and the smallest value in mild water stress condition.
        

土壤水分胁迫对黄土丘陵区3个树种叶片气体交换的影响

附录4-8
中文摘要8-10
ABSTRACT10-12
1 引言13-24
    1.1 研究目的与意义13-15
    1.2 研究进展与现状15-24
        1.2.1 植物光合生理生态研究进展15-17
        1.2.2 环境因子对植物光合生理生态特征的影响17-21
        1.2.3 叶绿素荧光动力学机制研究进展21-24
2 材料与方法24-29
    2.1 试验地概况24-25
    2.2 试验材料25-26
    2.3 试验方法26-29
        2.3.1 试验布设与土壤水分梯度控制26
        2.3.2 光合作用-光响应曲线测定26-27
        2.3.3 光合作用-CO_2 响应曲线测定27-28
        2.3.4 叶绿素荧光参数的测定28-29
3 结果与分析29-55
    3.1 不同水分条件下3 个树种气体交换参数的光响应29-41
        3.1.1 光合速率的光响应29-32
        3.1.2 光合速率的光响应参数32-36
        3.1.3 蒸腾速率和气孔导度的光响应36-38
        3.1.4 水分利用效率的光响应38-41
    3.2 不同水分条件下3 个树种气体交换参数的CO_2 响应41-50
        3.2.1 光合速率的CO_2 响应41-43
        3.2.2 光合作用-CO_2 响应参数43-46
        3.2.3 蒸腾速率及气孔导度的CO_2 响应46-48
        3.2.4 水分利用效率的CO_2 响应48-50
    3.3 植物叶片叶绿素荧光参数的动态50-55
        3.3.1 土壤干旱胁迫对3 个树种F_0 与F_m 的影响51-53
        3.3.2 土壤干旱胁迫对3 个树种F_v/_Fm 的影响53
        3.3.3 土壤干旱胁迫对3 个树种φPSⅡ的影响53-54
        3.3.4 土壤干旱胁迫对3 个树种qP 和NPQ 的影响54-55
4 结论55-58
    4.1 植物叶片气体交换参数对土壤水分和光强具有明显的阈值响应.55-56
    4.2 土壤水分影响植物叶片气体交换参数对CO_2 浓度的响应过程56-57
    4.3 叶绿素荧光参数对土壤水分胁迫的影响57-58
5 讨论58-64
    5.1 植物叶片气体交换参数对土壤水分和光照强度的响应58-60
    5.2 不同水分下植物叶片气体交换参数对CO_2 浓度的响应60-62
    5.3 不同水分胁迫对植物叶片叶绿素荧光参数的影响62-64
参考文献64-76
致谢76-77
攻读学位期间发表论文情况77
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