Bioassay-directed isolation and identification of phytotoxic and fungitoxic acetylenes from Conyza canadensis.
نویسندگان
چکیده
Conyza canadensis (L.) Cronquist syn. (horseweed) is a problematic and invasive weed with reported allelopathic properties. To identify the phytotoxic constituents of the aerial parts, a systematic bioactivity-guided fractionation of the dichloromethane extract was performed. Three active enyne derivatives, (2Z,8Z)-matricaria acid methyl ester, (4Z,8Z)-matricaria lactone, and (4Z)-lachnophyllum lactone, were identified. The lactones inhibited growth of the monocot Agrostis stolonifera (bentgrass) and the dicot Lactuca sativa (lettuce) at 1 mg mL(-1), while the (2Z,8Z)-matricaria acid methyl ester was less active. In a dose-response screening of the lactones for growth inhibitory activity against Lemna paucicostata , (4Z)-lachnophyllum lactone was the most active with an IC50 of 104 μM, while the (4Z,8Z)-matricaria lactone was less active (IC50 of 220 μM). In a fungal direct bioautography assay, the two lactones at 10 and 100 μg/spot inhibited growth of the plant pathogenic fungi Colletotrichum acutatum , Colletotrichum fragariae , and Colletotrichum gloeosporioides . In a dose-response screening of the lactones against six different plant pathogenic fungi, (4Z,8Z)-matricaria lactone was more active than the commercial fungicide azoxystrobin on Col. acutatum , Col. fragariae , and Col. gloeosporioides at 30 μM and about as active as the commercial fungicide captan against Col. gloeosporioides , while (4Z)-lachnophyllum lactone was less active.
منابع مشابه
Assessment of glyphosate-resistant horseweed (Conyza canadensis L. Cronq.) and fleabane (Conyza albida Willd. ex Spreng) populations from perennial crops in Greece
The extended use of glyphosate resulted to its reduced efficacy against increasingly problematic weeds, such as Conyza spp. The objectives of this study were to determine the occurrence of glyphosate resistance in horseweed (C. canadensis) and fleabane (C. albida) populations in Greece, to evaluate the effect of weed growth stage on glyphosate efficacy under controlled environmental condit...
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متن کاملTransfer of glyphosate resistance: evidence of hybridization in Conyza (Asteraceae).
Transfer of herbicide resistance genes between crops and weeds is relatively well documented; however, far less information exists for weed-to-weed interactions. The hybridization between the weedy diploids Conyza canadensis (2n = 18) and C. ramosissima (2n = 18) was investigated by monitoring transmission of the allele conferring resistance to N-phosphonomethyl glycine (glyphosate). In a multi...
متن کاملcalcium oxalate crystals in Conyza canadensis (l.) cronq. and Conyza bonariensis (l.) cronq. (Asteraceae: Astereae)
Calcium oxalate crystals (CaOx) are found in most organs and tissues of many plant species. In this study the morphology and distribution of CaOx crystals in Conyza canadensis (L.) Cronq. and Conyza bonariensis (L.) Cronq. belonging to Asteraceae were investigated. CaOx crystals display a similar distribution in organs and tissues of C. canadensis and C. bonariensis. For the identification of C...
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ورودعنوان ژورنال:
- Journal of agricultural and food chemistry
دوره 60 23 شماره
صفحات -
تاریخ انتشار 2012