Influence of altered temperatures on allelopatic properties of Amaranthus cruentus L.

Abstract

The relationships between allelochemicals and environmental factors are a key factor for the growth of plants under rotation. We investigated the allelopathic potential of Amaranthus cruentus L, grown under different temperature conditions in in vitro bioassays. An inhibitory effect on germination and growth of lettuce (Lactuca sativa L.), tomato (Solanum lycopersicum L.), pepper (Capsicum annuum L.) and cucumber (Cucumis sativus L.) was observed when seeds were subjected to the leaf litter of Amaranthus cruentus. Analysis from our study indicated that germination percentage was significantly affected by growth temperatures (T) of the amaranth (P ˂ 0.0001), litter concentration (C) (P ˂ 0.0001), vegetable type (V) (P ˂ 0.0001), the T × V interaction (P = 0.0041) and V × C interaction (P ˂ 0.0001). Pepper was the most sensitive with a decline in germination percentage at increasing concentrations (0, 1 and 5 mg ml-1) of litter. Hypocotyl and seminal root lengths were adversely influenced by the plant litter for all the temperature treatments, although effects were most severe when exposed to the leaf litter of the hot temperature treatment. The inhibition caused by the litter was dependent on growth temperature and concentration, while each vegetable species showed different levels of sensitivity.

Keywords

• Amaranthus cruentus
• allelopathy
• vegetables
• germination
• hypocotyl
• seminal root