模拟水淹条件下乐安河河岸带优势植物丁香蓼生理生化指标的响应

Response of physiological and biochemical indices to simulated flooding conditions in Ludwigia prostrata, the dominant plant in the riparian zone of the Le’an River

为探究河岸带植物的耐淹机理其及生存策略,选择乐安河河岸带优势种丁香蓼(Ludwigia prostrata Roxb.)为试验材料,设置全淹(FULL)组、半淹(HALF)组、浸润(INF)组和对照(CK)组等4种不同水分条件进行室内培养,分析不同水淹时间内丁香蓼的叶片叶绿素、抗逆酶活性指标(超氧化物歧化酶SOD、过氧化氢酶CAT、过氧化物酶POD)、渗透调节物质(可溶性蛋白、可溶性糖)和丙二醛(Malondialdehyde,MDA)等生理生化指标的变化.结果显示,随着水淹强度的增加,丁香蓼植株受胁迫的伤害逐渐增大;水淹处理28 d后,浸润处理丁香蓼依然生长良好,全淹条件下的丁香蓼植株全部死亡.短时间的浸润处理和半淹处理对丁香蓼叶绿素总量无显著影响,但长时间水淹胁迫下的叶绿素总量均显著低于同期对照组(P<0.05).水淹胁迫下,丁香蓼叶片的SOD、POD和CAT活性随水淹时间的延长总体呈先升高后下降的趋势,而浸润组的CAT活性呈上升趋势,并在水淹28 d后与对照相比显著(P<0.05)升高41.6%.水淹处理能显著提高丁香蓼叶片的渗透调节物质的含量与MDA含量,且各指标随着水淹胁迫时间的延长呈先升高后下降趋势;在水淹胁迫21 d后,浸润组的可溶性蛋白、可溶性糖及MDA含量较CK组分别降低52.9%、25.9%及6.5%.上述研究结果表明丁香蓼能通过增加保护酶活性和渗透调节物质含量以适应水淹环境,是一种具有较强耐淹能力的物种;但高强度、长时间的水淹胁迫仍对其生长造成显著伤害.

This study explored the waterlogging mechanism and survival strategy of riparian plants under water flooding stress in the typical riparian zone of the Le’an River.The dominant species,Ludwigia prostrata(L.prostrate),was selected as the experimental material and was cultured in the laboratory,using soil pot methods,under four different water flooding intensity stresses,including control(CK),infiltration(INF),half-flooded(HALF),and full submergence(FULL).Changes in the characteristics of chlorophyll;the activity of anti-adversity enzymes,including superoxide dismutase(SOD),catalase(CAT),and peroxidase(POD);and osmotic adjustment substances,including soluble proteins and sugars and malondialdehyde(MDA),were determined in the leaves of L.prostrata.Stress damage of L.prostrata gradually increased with increasing flooding intensity.After flooding for 28 days,L.prostrata plants in the INF group still grew well,but plants in the FULL group died.Total chlorophyll content in the leaves of L.prostrata in the INF and HALF groups had no significant differences in the short period of growth,but their total chlorophyll content was significantly lower than that in the leaves of the control plants(P <0.05) in the long period of growth.SOD,POD,and CAT activities increased initially,but then decreased,with increasing flooding time in the FULL group.However,CAT activity in the INF group increased significantly by 41.6%(P <0.05),compared with the control group,after 28 days of flooding.The osmotic-regulating substance and MDA content in L.prostrata leaves significantly increased under the waterlogging treatment;however,these indices increased initially,but then decreased,with increasing flooding time.After 21 days of flooding,soluble protein,soluble sugar,and MDA content decreased by 52.9%,25.9%,and 6.5%,respectively,compared with the CK group.In summary,L.prostrata is a herbaceous species with strong flood resistance,which is achieved by increasing the activity of protective enzymes and the amount of osmotic regulation substances.However,more intense flooding and longer flooding times may still cause significant damage.