互花米草不同器官水浸液对3种红树植物幼苗的化感作用

摘要

外来入侵植物化学他感作用较多受到关注,然而中国滨海湿地最常见的外来入侵种互花米草(Spartina alterniflora)对于红树植物幼苗的化学他感影响鲜见报道.选用互花米草根、茎、叶的3个浓度梯度(0.125、0.25和0.5g mL-1)水浸液为处理液,通过盆栽试验,研究其对秋茄(Kandelia candel)、无瓣海桑(Sonneratia apetala)和拉关木(Leguncalaria racemosa)的幼苗生长及根部抗氧化物酶活性的影响.互花米草根、茎和叶0.5g mL-1水浸液显著降低3种红树植物幼苗总生物量(地上生物量+地下生物量),0.125g mL-1水浸液对3种红树植物幼苗总生物量无显著影响.互花米草各器官0.125g mL-1水浸液总体上对3种红树植物幼苗根部超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性无显著影响;互花米草各器官0.5g mL-1水浸液显著降低拉关木根部抗氧化物酶活性,对于秋茄和无瓣海桑,互花米草植株0.5g mL-1水浸液对抗氧化物酶活性或促进或无影响.互花米草水浸液对红树植物土著种和外来引进种幼苗生长及根部抗氧化物酶活性均具有较明显的化学他感作用,这可能是互花米草成功入侵中国福建沿海秋茄红树林生态系统的重要机制之一.%Allelopathic effect of alien invasive plants had been paid more attention,however,the ob-servations for the allelopathic effect of alien invasive species Spartina alterniflora on mangrove seeding are still limited.The allelopathic effects of aqueous extracts of the root,stem and leaf of S.alterniflora, at the concentrations of 0.125,0.25 and 0.5 g mL-1,on the seeding growth of Kandelia candel,Son-neratia apetala and Leguncalaria racemosa, and the roots antioxidant defense system were determined by mesocosm experiment.The aqueous extracts of the root,stem and leaf at a concentrations of 0.5 g mL-1decreased the total biomass(above and below ground biomass)of three mangrove species seeding,but the aqueous extracts of the root,stem and leaf at a concentrations of 0.125 g mL-1dem-onstrated no effects on the total biomass of three mangrove species seeding.There was no significant effects of the aqueous extracts of the root,stem and leaf at a concentrations of 0.125 g mL-1on the ac-tivities of superoxide dismutase(SOD), peroxidase(POD)and catalase(CAT)of the roots of three mangrove species seeding,the aqueous extracts of the root,stem and leaf at a concentrations of 0.5 g mL-1significantly decreased the activities of SOD, POD and CAT of the root of L.racemosa seeding, and,for the K.candel,S.apetala,the aqueous extracts at a concentrations of 0.5 g mL-1increased or did not affect the roots antioxidant defense system.Aqueous extracts of the root, stem and leaf of S.alterniflora showed distinct allelopathic effects on seeding growth and roots antioxidant defense sys-tem of native and alien mangrove seeding,which may be one of the mechanisms of the successful inva-sion of S.alterniflora to K.candel ecosystem in the coastal region of Fujian,China.