title: Phytotoxic effects and a phytotoxin from the invasive plant Xanthium italicum Moretti.
abstract: The allelopathic effects of different parts of the plant Xanthium italicum Moretti were evaluated by conducting bioassays against two dicot plants, amaranth (Amaranthus mangostanus L.) and lettuce (Lectuca sativa L.), and two monocot plants, wheat (Triticum aestivum Linn) and ryegrass (Lolium multiforum). Leaf and fruit extract possessed the strongest biological activity, killing all seeds of four test species at 0.05 g/mL concentration. Fruits were chosen for further investigation because of their high biomass. This led to the isolation and identification of a phytotoxin-Xanthinosin-a known sesquiterpene lactone. Xanthinosin significantly affected seedling growth of all test species at 160 µM concentration. Cultivating seeds in 800 μM xanthinosin solution resulted in a great decrease in seedling growth of all test species, especially for the two dicot plants, amaranth and lettuce, whose root length was inhibited by 78% and 89%, respectively. By comparison, the numbers were 69% lower for wheat, and 66% for ryegrass, two monocot plants. When treated with 4 mM xanthinosin solution, seed germination of all test plants was almost completely inhibited. The possibility of utilizing xanthinosin as an eco-friendly herbicide was discussed.
authors.affiliation: Key Laboratory of Biogeography and Bioresource in Arid Land, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China. shaohuaconnie@yahoo.com
authors.forename: Hua
authors.initials: H
authors.lastname: Shao
authors.forename: Xiaoli
authors.initials: X
authors.lastname: Huang
authors.forename: Xiaoyi
authors.initials: X
authors.lastname: Wei
authors.forename: Chi
authors.initials: C
authors.lastname: Zhang
mesh_terms: D019659:Asteraceae / Q000737:chemistry*; D005638:Fruit / Q000187:drug effects; D007783:Lactones / Q000737:chemistry / Q000302:isolation & purification / Q000633:toxicity*; D010936:Plant Extracts / Q000633:toxicity*; D018517:Plant Roots / Q000737:chemistry / Q000187:drug effects; D018520:Plant Shoots / Q000187:drug effects; D018547:Plant Stems / Q000737:chemistry; D012717:Sesquiterpenes / Q000737:chemistry / Q000302:isolation & purification / Q000633:toxicity*; D012997:Solvents
chemical_list: D007783:Lactones; D010936:Plant Extracts; D012717:Sesquiterpenes; D012997:Solvents; C527331:xanthinosin