【作者】 陈超；

【导师】 王堃；

【作者基本信息】 中国农业大学 ， 草业科学， 2014， 博士

【摘要】 我国西南喀斯特山区是世界东亚喀斯特地貌的核心分布区,其基本特征是生境的严酷性和生态的脆弱性,严酷性集中表现为岩石裸露率高、土壤浅薄零星、水分和养分供应不足且保存能力差；其脆弱性表现为环境容量小、土地承载力低、抗干扰能力弱,受干扰后自然恢复速度慢、难度大。虽然喀斯特山区地处亚热带湿润气候带,但是由于我国喀斯特山区主要分布在云贵高原地区,中低海拔地区时常发生季节性干旱,高海拔地区冬季经常发生低温寒害。作为中国喀斯特山区核心分布区的贵州省,自实施草地生态畜牧业以来大力推广以灌丛草地饲养黑山羊的模式,然而由于季节性干旱和寒害等原因,需要筛选适合当地区域的耐旱或耐寒灌木品种进行推广应用。本研究选择4种干旱地区常用灌木(马棘Indigofera pseudotinctoria Mats.、二色胡枝子Leapedeza bicolor Turcz.、紫穗槐Amorpha fruiticosa Linn.口多花木兰Indigofera amblyantha、7种寒冷地区常用灌木(白刺花Sophora viciifolia Hance、多花木兰Indigofera amblyantha、刺槐Robinia pseudoacacia L.、木豆Cajanus cajan(L.)Millspaugh、车桑子Dodonaea viscosa (Linn.) Jacq. Enum、黄花决明Senna sulfurea(Collad.)H.S.Irwin&Barneby和猪屎豆Crotalaria pallida Ait为试验材料；采用野外观察、实验室分析和数理统计等方法进行胁迫研究,得出如下结论：(1)水分胁迫显著抑制了马棘、二色胡枝子、紫穗槐和多花木兰等4种灌木株高和叶面积生长,其抑制程度随胁迫强度的增加和胁迫时间的延长而增加。随水分胁迫强度增加,4种灌木叶片相对含水量和叶片持水力呈下降趋势。(2)马棘、二色胡枝子、紫穗槐和多花木兰等4种灌木的Chlorophyll a (Chla)含量随胁迫时间的延长呈先增加后下降的变化趋势,Chlorophyll a/b (Chla/b)值在胁迫初期变化较平稳,胁迫中期开始大幅度下降,末期又呈现小幅度上升的变化趋势。从胁迫末期与初期变化幅度来看,紫穗槐的Chla、Chlb与Chla/b值下降幅度均最小,胡枝子次之,马棘变化幅度最大。随水分胁迫时间延长,4种灌木叶片的脯氨酸、可溶性糖、可溶性蛋白含量呈增加趋势,但随胁迫强度的增加,可溶性蛋白含量下降,脯氨酸与可溶性糖含量在不同胁迫时期也呈不同程度增加减缓的趋势。(3)马棘、二色胡枝子、紫穗槐和多花木兰等4种灌木叶片Malondial dehyde (MDA)含量及相对电导率随水分胁迫强度增加而增加。胁迫初期4种灌木叶片MDA含量及相对电导率上升幅度较小,重度胁迫后期,马棘与多花木兰的原生质膜受到严重伤害,造成细胞内离子的大量外渗,导致其相对电导率分别达到对照的6.90、6.68倍；而紫穗槐与胡枝子在重度胁迫后期仅为对照的1.97倍、2.00倍,说明紫穗槐、胡枝子渗透调节能力较其它两种灌木强。4种灌木中Superoxide dismutase (SOD)、Peroxidase (POD)、Catalase (CAT)等酶活性都维持在较高水平,在不同处理时期表现出不同的酶活性,并且它们之间保持着一定的互补性。随水分胁迫强度增加,SOD、POD、CAT活性除紫穗槐持续增加外,其它3树种均呈先升高后降低的变化趋势,并且伴随胁迫时间的延长,抗旱性较弱的树种最早呈现出下降趋势。(4)马棘、二色胡枝子、紫穗槐和多花木兰等4种灌木在所测定的几项抗旱指标上均存在差异,说明各物种在抗旱性上表现出多样性。不同指标鉴定出不同灌木抵御干旱的能力强弱不一致,这说明它们在遭遇干旱胁迫时,采取不同的适应机制。利用模糊隶属函数法对应试灌木的抗旱性进行综合评价结果为：紫穗槐>二色胡枝子>马棘>多花木兰。(5)对抗寒性试验中的7种应试灌木(白刺花、多花木兰、刺槐、木豆、车桑子、黄花决明、猪屎豆),其抗寒性等级分别为强抗寒性(白刺花、多花木兰、刺槐)、中等抗寒性(车桑子、黄花决明)和差抗寒性(木豆、猪屎豆)。(6)在低温胁迫末期,白刺花的叶绿素含量大于其它灌木,最弱的为黄花决明和车桑子；在不同低温胁迫下,猪屎豆叶片中MDA含量较高,而多花木兰和白刺花叶片中MDA含量相对较低。(7)7种抗寒性试验的应试灌木的抗氧化酶活性在低温胁迫下存在差异,并且抗氧化酶清除自由基的能力是有限的,抗寒性弱的猪屎豆其抗氧化酶活性要低于其它灌木,抗寒性强的白刺花、多花木兰其抗氧化酶活性要高；利用模糊隶属函数法对7种应试灌木的抗寒性进行综合评定,其抗寒性由强到弱的顺序为：白刺花>刺槐>多花木兰>车桑子>黄花决明>木豆>猪屎豆。更多还原

【Abstract】 Southwest karst mountainous area in China is the core distribution area in Eastern Asia of the world karst, its basic features are harsh habitat and ecological fragility, the severity of the habitat is highly concentrated expression of the high rate of bare rock, the soil is shallow and sporadic, inadequate supply of water and nutrients, and the ability to hold is poor; the presentation of fragility to environmental capacity is small, the capacity of land carrying is low, the anti-interference ability is weak, and the recovery after natural disturbance is slow and difficult. Although karst mountain area is located in Humid subtropical climate zone, because of the karst mountains are mainly distributed in the Yunnan-Guizhou Plateau, low-lying areas occurs seasonal drought frequently and high altitude chilling injury occurs frequently in winter. Guizhou Province as the core distribution area in Chinese karst area, since the implementation of the grassland ecosystem, promoting the feeding patterns of black goat with shrub grassland breeding, however, due to seasonal drought and chilling and other reasons, it entails to be selected suitable anti-drought or anti-cold shrub varieties in local areas to generalized application. In this study, four kinds of common shrubs in arid areas (Indigofera pseudotinctoria Mats、Leapedeza bicolor Turcz、Amorpha fruiticosa Linn and Indigofera amblyantha), seven kinds of shrub commonly used in cold regions (Sophora davidii, Indigofera amblyantha, Robinia pseudoacacia L., Semen Cajani Cajani, Radix Dodonaeae Viscosae, Cassia) were chosen to be test materials; Using field observations, laboratory analysis and mathematical statistics and other methods to do stress research, as the following conclusions:The growth of height and Leaf area of Indigofera pseudotinctoria Mats、Leapedeza bicolor Turcz.、 Amorpha fruiticosa Linn and Indigofera amblyantha were inhibited significantly under water stress, along with the increasing time and degree of water stress, the degree of inhibitory increased. With the increasing degree of water stress, the relative water content of leaves of the four seedlings decreased.(2) With the increasing time of water stress, the trend of Chlorophyll a content and Chlorophyll b content of Indigofera pseudotinctoria Mats、Leapedeza bicolor Turcz.、Amorpha fruiticosa Linn and Indigofera amblyantha emerged first, and then decreased. The ratio of Chlorophyll a to b changed slowly at the early stage of stress treatment, then decreased substantially, and had a small increase at the later stage of stress treatment. To the later stage of stress treatment, Chlorophyll a, Chlorophyll b and the ratio of Chlorophyll a to b of Amorpha fruiticosa Linn had a minimum decline compared with the early stage of stress treatment, follwed by Leapedeza bicolor Turcz, and Indigofera pseudotinctoria Mats is the maximum. With the increasing time of water stress, the Proline content, Soluble sugar content and Soluble protein content of four shrubs showed an upward trend. The Soluble protein content decreased while the increasing degree of water stress. The trend of Proline content and Soluble sugar content increased slowly in different stage of stress treatment.(3) With the increasing degree of water stress, the Malondialdehyde content and the relative electrical conductivity rate showed an upward trend. With the increasing time of water stress, the trend of these increased slowly at the early stage of stress treatment,but had a significant increasing trends in the end. Severe stress Indigofera amblyantha, and Indigofera pseudotinctoria Mats conductivity were severely injured, resulting in a large number of extravasation of intracellular ion, which caused that conductivity, respectively,6.90,6.68times; While Amorpha fruiticosa Linn and Leapedeza bicolor Turcz only control in severe stress late1.97times and2.00times, indicating that Amorpha fruiticosa Linn and Leapedeza bicolor Turcz osmotic adjustment ability than the other two shrubs. The activities of SOD, POD, CAT activity in the four shrubs at a higher level showed a different enzyme activities in the different treatment process, and they maintain a certain degree of complementarity. With the increasing degree of water stress, the trend of SOD, POD and CAT activity of three shrubs emerged first and then decreased, while Amorpha fruiticosa Linn maintained an upward trend all long. However as increasing time of water stress, those of less tolerant shrubs firstly appeared a declining trend.(4) Indigofera pseudotinctoria Mats、Leapedeza bicolor Turcz.、Amorpha fruiticosa Linn and Indigofera amblyantha, there are differences in the diversity of species in drought resistance on the performance of several drought indicators listed. Strengths and weaknesses of different indicators to identify the different shrubs from drought inconsistent, indicating that they take different adaptive mechanisms to drought stress. Through the method of subordinate (anti-subordinate) function, comprehensive assessment on the drought resistant index of four shrubs indicated that the order of drought resistance capability of four shrubs was Amorpha fruiticosa Linn> Leapedeza bicolor Turcz> Indigofera pseudotinctoria Mats> Indigofera amblyantha.(5) Cold resistance tests on seven candidates shrubs (Sophora davidii, Indigofera amblyantha, Robinia pseudoacacia L., Semen Cajani Cajani, Radix Dodonaeae Viscosae, Cassia glauca Lam and Crotalaria), its hardiness level were strong cold resistance (Sophora davidii, Indigofera amblyantha, Robinia pseudoacacia L.), medium cold resistance (Semen Cajani Cajani and Radix Dodonaeae Viscosae) and poor cold resistance (Cassia glauca Lam and Crotalaria).(6) To the later stage of low temperature stress, Chlorophyll content of Sophora viciifolia and Robinia pseudoacacia are great than other shrubs, the weakest is Dodonaea viscose and Cassia alata Linn.; Under low temperature stress, the MDA content of Crotalaria is higer, while the MDA content of Sophora viciifolia and Robinia pseudoacacia were lower.(7) Under low temperature stress of7kinds of shrubs’activity of antioxidant was different and the antioxidant enzymes activity was limited. The less tolerant shrub’s(crotalaria) activity of antioxidant was lower, The tolerant shrub’s (Sophora viciifolia、Robinia pseudoacacia) activity of antioxidant was higher. Using the methods of subordination and counter-subordination function, we can get a comprehensive assessment of cold resistance, the cold resistance order is Sophora viciifolia>Robinia pseudoacacia> Indigofers amblyatha> Dodonaea viscose> Cassia alata Linn> pigeonpea> crotalaria.更多还原