Metabolic Activity of Wheat and Ryegrass Plants in Competition

Abstract

-Ryegrass is an annual cycle Poacea, often considered as a weed in wheat crops. The goal of this study was to analyze oxidative stress and enzyme activity of wheat and ryegrass cultures in response to stress caused by the competition between crop and weed, in two development stages. The experiment was conducted in completely randomized design, with eight replications, in replacement series, with a population of 64 plants per pot. Treatments consisted of proportions of ryegrass and wheat plants arranged in replacement series. The tested proportions were: 100/0 (pure wheat stand), 75/25, 50/50, 25/75 and 0/100% (pure ryegrass stand). The evaluated variables were: hydrogen peroxide (H 2 O 2 ) content, thiobarbituric acid-reactive species (TBARS), electrolyte leakage and activity of superoxide dismutase (SOD), ascorbate peroxidase (APX) and catalase (CAT) antioxidant enzymes. Culture and the damages caused by ryegrass competition varied according to the plant developmental stage. Both for wheat and rygrass culture, intraspecies competition caused higher oxidative stress, with increasing H 2 O 2 and TBARS contents and electrolyte leakage. SOD, CAT and APX activity increased in the culture during interspecies competition. In ryegrass, interspecies competition also increased SOD and CAT activity, whereas weed monoculture caused an increase in the APX enzyme. Generally speaking, variable behaviors were similar between the tillering and stem elongation stages. Keywords:Triticum aestivum, Lolium multiflorum, stress, competitiveness. RESUMO -O azevém é uma

Defenses Against ROS in Crops and Weeds: The Effects of Interference and Herbicides

“…Studies have demonstrated alterations in ROS production in crops as a response to weed interference, as well as changes in enzymatic activity and gene expression of antioxidant components [ 7 , 11 , 13 , 14 , 33 ]. Current research is needed to tie weed interference with crop oxidative stress more closely.…”

“…One gap in our knowledge is the dynamic effects of weed interference on crops and changes rendered by herbicide exposure, especially at the molecular level. Antioxidant response to stress caused by weed interference and herbicide treatment in crops and weeds have been recent subjects of investigation [ 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 ]. Both weed interference and herbicide treatment stimulate the synthesis of antioxidant molecules in plants in response to stress [ 10 , 11 , 15 , 16 ].…”

“…Antioxidant response to stress caused by weed interference and herbicide treatment in crops and weeds have been recent subjects of investigation [ 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 ]. Both weed interference and herbicide treatment stimulate the synthesis of antioxidant molecules in plants in response to stress [ 10 , 11 , 15 , 16 ]. Alterations in enzymatic antioxidants such as superoxide dismutase, catalase, ascorbate peroxidase, and peroxidase have been documented in crops and weeds in response to weed interference [ 11 , 13 , 14 , 17 ] and herbicide exposure [ 1 , 5 , 18 , 19 , 20 ] together with the synthesis of ROS and causing lipid peroxidation.…”

“…Both weed interference and herbicide treatment stimulate the synthesis of antioxidant molecules in plants in response to stress [ 10 , 11 , 15 , 16 ]. Alterations in enzymatic antioxidants such as superoxide dismutase, catalase, ascorbate peroxidase, and peroxidase have been documented in crops and weeds in response to weed interference [ 11 , 13 , 14 , 17 ] and herbicide exposure [ 1 , 5 , 18 , 19 , 20 ] together with the synthesis of ROS and causing lipid peroxidation. Also, antioxidant-related gene expression and protein synthesis appear to be responsive to those stressors [ 8 , 9 , 12 , 16 ].…”

Glyphosate resistant ryegrass competitive ability

“…From the enzymatic point of view, resistant and susceptible ryegrass plants presented differentiated expression of enzymes linked to oxidative stress under intra and inter-biotypic competition. When the susceptible ryegrass was in competition with resistant ryegrass, the activities of the SOD and CAT enzymes were increased; these enzymes are produced to combat reactive oxygen species that are detrimental to plant development (Apel & Hirt, 2004;Agostinetto et al, 2017b).…”