Physiological aspects of redroot pigweed’s (Amaranthus retroflexus L.) allelopathic effects on cucumber plants

Allelopathy is one of the most important interactions among plants in the natural ecosystems and agricultural fields. Weeds could reduce crops yield in farms due to competition as well as their allelopathic effects. Redroot pigweed is one of the most common weeds in the worldwide with well-known allelopathic effects. In order to evaluation of physiological aspects of redroot pigweed allelopathic effects on cucumber, an experiment was conducted as factorial based on completely randomized design with three replications. Cucumber plants were cultivated hydroponically at greenhouse conditions on a solid substrate (perlite) and treated with 0 and 0.25% of the redroot pigweed leachate. Redroot pigweed s leachate caused 1) increasing in stomata opening probably by interference of some allelopathic compounds such as ferulic acid with the plant hormonal system, 2) increasing in photosynthetic pigments contents, especially in carotenoids content that is involved in the xanthophyll cycle, 3) reduction in relative water content due to higher stomata opening and reduction in water uptake, 4) decreasing in total soluble protein content possibly by reduction in either biosynthesis or half-life, 5) induction of oxidative stress followed by increases in the antioxidant enzymes activity including catalase and peroxidase, and consequently reduced plants growth and biomass production in treated plants. Therefore, allelopathic effects of redroot pigweed, which finally reduce treated plants growth and ultimately lead to plant death happen because of the negative effects of the allelochemicals on various physiological aspects of the receiver plants

کلیدواژه ها:

Allelopathy ، Growth ، Physiological parameters ، Redroot pigweed ، Cucumber