Allelochemical stress causes inhibition of growth and oxidative damage in Lycopersicon esculentum Mill

Abstract

The aim of this study was to analyse the effect of allelochemical stress on Lycopersicon esculentum growth. Our results showed that allelochemical stress caused by Sicyos deppei aqueous leachate inhibited root growth but not germination, and produced an imbalance in the oxidative status of cells in both ungerminated seeds and in primary roots. We observed changes in activity of catalase (CAT), ascorbate peroxidase (APX), superoxide dismutase (SOD), glutathione reductase (GR) and the plasma membrane NADPH oxidase, as well as in the levels of H 2 O 2 and O 2• -in seeds at 12 and 24 h, and in primary roots at 48 and 72 h of treatment, which could account for the oxidative imbalance. There were changes in levels of expression of the mentioned enzymes, but without a correlation with their respective activities. Higher levels of membrane lipid peroxidation were observed in primary roots at 48 and 72 h of treatment. No effect on the expression of metacaspase and the PR1 was observed as indicators of cell death or induction of plant defence. This paper contributes to the understanding of plant-plant interactions through the phytotoxic allelochemicals released in an aqueous leachate of the weed S. deppei , which cause a negative effect on other plants.

Phytotoxicity of Sicyos deppei during tomato germination and its effects on the role of ABA and cell wall enzymes

“…According to the results reached in this work and to those obtained from other studies about the aqueous leachate of Sicyos deppei (Romero-Romero et al, 2005;Lara-Núñez et al, 2006, we provide a more complete understanding of how the compounds present in this extract cause phytotoxicity in tomato germinating seeds, as evidenced through a delay in germination process and radicle growth inhibition.…”

“…We have shown through in vitro assays that watersoluble compounds delay tomato seed germination and inhibit radicle growth. Sicyos deppei phytotoxicity has been associated with diverse metabolic processes, such as the inhibition of the H + -ATPase in the plasma membrane and tonoplast (Romero-Romero et al, 2005), increases in ROS levels, membrane lipid peroxidation, effects on the activity of antioxidant enzymes, and the inhibition of NADPH oxidase activity (Lara-Núñez et al, 2006). Furthermore, the delayed of root protrusion in seeds exposed to S. deppei aqueous leachate has been associated with the reduced activity of cell wall-degrading enzymes, changes in carbohydrate content, and increased levels of abscisic acid (ABA) (Lara-Núñez et al, 2009).…”

Phytotoxicity induced by Phragmites australis: an assessment of phenotypic and physiological parameters involved in germination process and growth of receptor plant

“…Allelopathic potential is an important attribute to the success of an invasive species in natural ecosystems, particularly when the species produces novel biochemical weapons (Callaway & Ridenour 2004). Interactions associated with allelochemicals produced by invasive or native plant species have the potential to impact seed germination, seedling growth, development, and establishment of neighboring plant species, as well as of the same species, in both natural and agricultural systems (Dorning & Cipollini 2006;Lara-Nu´n˜ez et al 2006).…”

Allelopathic Compounds as Oxidative Stress Agents: Yes or NO

“…Despite well-described overproduction of ROS in tomato plants, observed mainly in short-term reaction to S. deppei leachates, the authors stated that they believe that it is not an oxidative damage responsible for toxicity of the plant (Cruz-Ortega et al 2007), so it is possible that generated ROS may only act as signals activating cascade of other events leading to cell malformations. On the other hand, studies of Lara-Nuñez et al (2006) showed decline inactivity of NADPH oxidase in roots of tomato exposed to leachate of S. deppei. As activity of this enzyme is known to control root development and growth by generation of ROS (Foreman et al 2003), it could be possible that the inhibition of tomato root elongation by allelochemicals of S. deppei might be due to the inhibition of NADPH oxidase, and the subsequent reduction in root ROS level in prolonged treatment.…”

“…Water extract from sunflower leaves inhibited seed germination and growth of mustard (Sinapis alba L.) (Oracz et al 2007), due to over-accumulation of ROS, which were not sufficiently scavenged by activated antioxidant enzymatic system (CAT, SOD and glutathione reductase-GR). Allelochemical stress caused by Sicyos deppei G. Don, an invasive annual tendril-bearing vine, endemic to Mexico, was specified by producing an oxidative imbalance evidenced by alteration in ROS generation and modification of antioxidant cellular system in roots of tomato (Solanum lycopersicum L.) (Lara-Nuñez et al 2006;Cruz-Ortega et al 2007). Despite well-described overproduction of ROS in tomato plants, observed mainly in short-term reaction to S. deppei leachates, the authors stated that they believe that it is not an oxidative damage responsible for toxicity of the plant (Cruz-Ortega et al 2007), so it is possible that generated ROS may only act as signals activating cascade of other events leading to cell malformations.…”