【作者】 赵洁；

【导师】 郝文芳；

【作者基本信息】 西北农林科技大学 ， 植物学， 2013， 硕士

【摘要】 为探究美丽胡枝子（Lespedeza formosa）、二色胡枝子（Lespedeza bicolor）和牛枝子（Lespedeza potaninii）对干旱、增强UV-B辐射以及二者复合处理的生理响应，本研究采用盆栽试验，研究了正常生长（CK）、中度干旱胁迫（D1）、重度干旱胁迫（D2）、低强度UV-B辐射胁迫（U1）、高强度UV-B辐射胁迫（U2）、中度干旱与低强度UV-B辐射复合胁迫（D1U1）、中度干旱与高强度UV-B辐射复合胁迫（D1U2）、重度干旱与低强度UV-B辐射复合胁迫（D2U1）以及重度干旱与高强度UV-B辐射复合胁迫（D2U2）下三种胡枝子叶片中抗氧化酶活性、渗透调节物质含量、紫外吸收物质含量以及丙二醛含量的动态响应。旨在通过分析三种胡枝子在不同逆境条件下以上指标的动态变化规律，以及各植物的抗氧化能力，为优良牧草的开发提供一定的科学依据，也为陕北黄土高原生态恢复建设提供必要的理论基础。主要得到以下结论：1、三种胡枝子对干旱胁迫的生理响应各梯度干旱处理均对三种胡枝子造成不同程度的胁迫，并且其伤害程度因胁迫强度和植物特性不同而异。与重度干旱胁迫相比，中度干旱胁迫给美丽胡枝子和牛枝子带来的氧化胁迫程度更小，但对于二色胡枝子情况则完全相反，中度干旱胁迫下其受到的氧化胁迫更严重。根据隶属函数综合评价分析，无论中度或重度干旱胁迫下，美丽胡枝子和二色胡枝子均具有较强的抗氧化能力，牛枝子抗氧化能力均最弱。所以，美丽胡枝子和二色胡枝子对干旱胁迫具有较强的适应性。2、三种胡枝子对增强UV-B辐射胁迫的生理响应不同强度UV-B辐射处理对三种胡枝子均造成不同程度的胁迫，并且其伤害程度因胁迫强度和植物特性不同而异。与低强度UV-B辐射胁迫相比，高强度UV-B辐射胁迫给三种胡枝子带来的氧化胁迫程度更大；与美丽胡枝子相比，各处理对二色胡枝子和牛枝子造成的氧化胁迫均更大。根据隶属函数综合评价分析，无论低强度或高强度UV-B辐射胁迫下，美丽胡枝子和二色胡枝子均具有较强的抗氧化能力，牛枝子抗氧化能力均最弱。所以，美丽胡枝子和二色胡枝子对增强UV-B辐射胁迫具有较强的适应性。3、三种胡枝子对中度干旱与不同强度UV-B辐射复合胁迫的生理响应与单因子干旱处理相比，中度干旱与不同强度UV-B辐射复合处理对美丽胡枝子造成的氧化胁迫没有明显加剧；中度干旱与低强度UV-B辐射复合处理后期对二色胡枝子造成的氧化胁迫有一定程度的加剧，中度干旱与高强度UV-B辐射复合处理对二色胡枝子造成的氧化胁迫反而降低；中度干旱与高强度UV-B辐射复合处理对牛枝子造成的氧化胁迫加剧。根据隶属函数综合评价分析，无论中度干旱与低强度UV-B辐射或高强度UV-B辐射复合胁迫下，美丽胡枝子和二色胡枝子均具有较强的抗氧化能力，牛枝子抗氧化能力均最弱。所以，美丽胡枝子和二色胡枝子对中度干旱与不同强度UV-B辐射复合胁迫具有较强的适应性。4、三种胡枝子对重度干旱与不同强度UV-B辐射复合胁迫的生理响应与单因子干旱处理相比，重度干旱与不同强度UV-B辐射复合处理对美丽胡枝子造成的氧化胁迫没有明显加剧；重度干旱与低强度UV-B辐射复合处理后期对二色胡枝子造成的氧化胁迫有一定程度的加剧，重度干旱与高强度UV-B辐射复合处理对二色胡枝子造成的氧化胁迫反而降低；重度干旱与高强度UV-B辐射复合处理对牛枝子造成的氧化胁迫加剧。根据隶属函数综合评价分析，无论重度干旱与低强度UV-B辐射或高强度UV-B辐射复合胁迫下，美丽胡枝子和二色胡枝子均具有较强的抗氧化能力，牛枝子抗氧化能力均最弱。所以，美丽胡枝子和二色胡枝子对重度干旱与不同强度UV-B辐射复合胁迫具有较强的适应性。更多还原

【Abstract】 The study investigated the effects of enhanced UV-B radiation and drought stress, aswell as their combined stress, on lipid peroxidation, the activities of antioxidant enzymes,osmotic adjustment substances and concentrations of UV-B absorbing compounds in threeLespedezas (Lespedeza bicolor Turcz., Lespedeza potaninii Vass., Lespedeza formosaKoehne). There were nine different treatments in our experiment: control group (CK),moderate drought stress (D1), severe drought stress (D2), low-intensity UV-B radiation stress(U1), high-intensity UV-B radiation stress (U2), moderate drought and low-intensity UV-Bradiation combined-stress (D1U1), moderate drought and high intensity UV-B radiationcombined-stress (D1U2), severe drought and low intensity UV-B radiation combined-stress(D2U1), severe drought and high-intensity UV-B radiation combined-stress (D2U2). Themain objectives of the study is to analyze the dynamic reponse of the above indicators ofthree Lespedezas under different stress conditions, as well as the antioxidant capacity of them,in order to select more suitable species for vegetation restoration of the Loess Plateau. Thefollowing conclusions:1、The physilogical response of three Lespedezas to drought stressBoth moderate drought stress and severe drought stress have caused varying degrees ofoxidantive stress on three Lespedezas, and the damage extent varies due to the stress intensityand plant characteristics. Compared with the severe drought stress, moderate drought stresscaused lighter oxidative stress on Lespedeza formosa and Lespedeza potaninii; moderatedrought stress caused more significant oxidative stress on Lespedeza bicolor. According tosubordinate function values analysis, regardless of the moderate drought stress or severe droughtstress, Lespedeza formosa and Lespedeza bicolor. were more tolerant to the stresses than Lespedezapotaninii.2、The physilogical response of three Lespedezas to enhanced UV-B radiation stressBoth intensities of UV-B radiation have caused varying degrees of oxidantive stress on three Lespedezas, and the damage extent varies due to the stress intensity and plant characteristics.Compared with low-intensity UV-B radiation stress, high-intensity UV-B radiation stresscaused more significantly oxidative stress on three Lespedezas; compared with Lespedezaformosa, all treatments caused more significant oxidative stress on Lespedeza bicolor andLespedeza potaninii. According to subordinate function values analysis, regardless of thelow-intensity or high-intensity UV-B radiation, Lespedeza formosa and Lespedeza bicolor. weremore tolerant to the stresses than Lespedeza potaninii.3、The physilogical response of three Lespedezas to moderate drought and different-intensities UV-B radiation combined-stressCompared with the single drought stress, moderate drought with different intensities UV-Bradiation did not cause significantly oxidative stress on Lespedeza formosa; moderatedrought with low-intensity UV-B radiation increased oxidative stress on Lespedeza bicolor inthe later period of treatment; moderate drought with high-intensity UV-B radiationadecreased the oxidative stress on Lespedeza bicolor; moderate drought with high-intensityUV-B radiationa incresed the oxidative stress on Lespedeza potaninii. According to subordinatefunction values analysis, regardless of the moderate drought with low-intensity or high-intensityUV-B radiation, Lespedeza formosa and Lespedeza bicolor. were more tolerant to the stresses thanLespedeza potaninii.4、The physilogical response of three Lespedezas to severe drought and different-intensities UV-B radiation combined-stressCompared with the single drought stress, severe drought with different intensities UV-Bradiation did not cause significantly oxidative stress on Lespedeza formosa; severe droughtwith low-intensity UV-B radiation increased oxidative stress on Lespedeza bicolor in the laterperiod of treatment; severe drought with high-intensity UV-B radiationa decreased theoxidative stress on Lespedeza bicolor; severe drought with high-intensity UV-B radiationaincresed the oxidative stress on Lespedeza potaninii. According to subordinate function valuesanalysis, regardless of the severe drought with low-intensity or high-intensity UV-B radiation,Lespedeza formosa and Lespedeza bicolor. were more tolerant to the stresses than Lespedeza potaninii.更多还原