Allelopathic potential of Egyptian halophytes Arthrocnemum macrostachyum and Halocnemum strobilaceum from two coastal areas

摘要

We studied the allelopathic effects of two halophytes (Arthrocnemum macrostachyum and Halocnemum strobilaceum), growing in coastal areas of Burj Alarab and Manzala, Egypt, on the seed germination, chlorophyll content, leaf area, shoot length, and esterase and superoxide dismutase activities of Eruca sativa. The shoot aqueous extracts (0, 10, 20, 30 %) of both species had similar phytotoxicity. The H. strobilaceum was more allelopathic than A. macrostachyum. The samples from the Burj Alarab area were more phytotoxic than from the Manzala area. GC-MS analysis detected 27 and 67 compounds in Arthrocnemum and 25 and 31 in Halocnemum extracts, respectively. The dominant components in the Burg Alarab Arthrocnemum extract were: bicyclo[3.3.1]nonane-2,4-dione,3-(2,2-dimethyl propylidene) and 6,8-nonadien-2-one, 6-methyl-5-(1-methy lethylidene). In Manzala Arthrocnemum extracts, the antioxidant 3,4-dihydro-2h-1,5-(3 ''-t-butyl) benzodioxepine, nonadien and ethanonaphthalene, were most abundant. In the Burg Alarab Halocnemum extract dominant allelochemicals were : hexadecanoic acid and octadecenoic acid. While, in the Manzala extract the allelochemicals were : thieno[3,4-c] pyridine, 1,3,4,7-tetraphenyl, benzothieno[2,3-c]quinolin-6(5h)-one, 2-methoxy (11.43 %). These results suggested the influence of habitat on the diversity, allelochemicals contents and allelopathy.