水淹胁迫对小蓬草(Conyza canadensis)的形态结构与生理生化特性的影响  

Effects of flooding stress on morphological structure and physiological and biochemical characteristics of Conyza canadensis

作　　者：杨玲 刘玲 胡馨月 甘丽萍 YANG Ling;LIU Ling;HU Xinyue;GAN Liping(College of Biology and Food Engineering,Chongqing Three Gorges University,Chongqing,404100,China)

机构地区：[1]重庆三峡学院生物与食品工程学院,重庆404000

出　　处：《生态科学》2020年第5期134-141,共8页Ecological Science

基　　金：重庆市2011协同创新项目,重庆科委项目(cstc2019jcyj-msxm1218);重庆市教委项目(KJ1710246)。

摘　　要：为研究水淹胁迫对三峡库区消落带重要物种小蓬草(Conyza canadensis)的生理生化特性及解剖结构的影响,以消落带区小蓬草为试验材料,设置全淹组(SG)和半淹组(Ss G)处理,测定与小蓬草在淹水过程中随着时间增长的生理指标与根系解剖变化。结果表明:水淹30 d,淹水组小蓬草相对叶面积和平均茎高与对照相比都显著降低,而根系主根长和侧根数量都显著高于对照组。SsG丙二醛(MDA)、脯氨酸、超氧化物歧化酶(SOD)活性及根系活力都升高,与对照组达到了显著差异,SG组的以上指标及可溶性还原糖都与对照组达到了显著差异,并且叶绿素、MDA和根系活力与SsG之间也达到了显著差异,解剖结构中,两种淹水处理的根系周皮细胞的气腔面积增加,木质部出现溶生型气腔;水淹50 d,SsG叶片边缘坏死,心部小叶存活,SG地上部分基本腐烂,两种淹水处理根系韧皮部出现坏死,木质部残存,解剖结构表明此时根系外围组织瓦解,生理指标测定表明,与对照相比,Ss G的叶绿素极显著降低,可溶性糖、MDA、脯氨酸及SOD都显著增加,SsG和SG根系活力较对照都显著降低。小蓬草在淹水过程中根系的存活时间超过叶片,根系在通气组织结构上启动响应机制,表明小蓬草在水淹胁迫中主要通过减少地上部分的生长量,增加地下根系的生长与结构的调节来适应水淹具有短期耐淹能力,这为库区消落带入侵物种的适应性及生态植被恢复提供参考数据。Conyza canadensis is an important plant for the hydro-fluctuation belt of the Three Gorges Reservoir Area.The aim of the research is to study the effects of flooding stress on the physio-biochemical characteristics and anatomical structure of Conyza canadensis.A total flooding group(SG)and a semi-flooding group(SsG)were set up to measure the physiological indexes and root anatomical changes of C.canadensis dynamically over time.The results showed that the relative leaf area and average stem height of C.canadensis in the flooded group were significantly lower than those of CK after 30 days of flooding,while the length of root main root and the number of fibrous root were significantly higher than those of CK.The activities of malondialdehyde(MDA),proline,superoxide dismutase(SOD)and root activity in SsG were increased significantly.For the SG,the above indexes of SsG and soluble reducing sugar of SG group were significantly different from CK.Moreover,the chlorophyll,MDA and root activity between SG and SsG also showed significant differences.For anatomical structure,the area of air chamber of peridermal cells of root was increased and lysigenous air chamber was appeared in xylem.After 50 days of flooding,the edge leaves of SsG were necrotized;the central lobule was survived;the aboveground part of SG was basically rotted;the phloem was necrotic and the xylem remained in both roots of SsG and SG.The anatomical structure showed that the periphery tissue of roots disintegrated at this moment.For the physio-biochemical characteristics,the chlorophyll content of SsG was significantly lower than that of CK.The soluble sugar,MDA,proline and SOD were significantly increased.The root activities of SsG and SG were significantly lower than those of CK.The survival time of roots was longer than that of leaves.The response mechanism initiation of roots in aeration structure of root indicated that C.canadensis had short-term drowning tolerance by reducing the growth of above-ground parts and increasing the growth and structure

关 键 词：三峡库区 小蓬草 水淹胁迫 生理生化 形态解剖 

分 类 号：Q945.78[生物学—植物学]