Interference of Volunteer Corn on Stress Metabolism and Yield of Dry Beans

Abstract

Dry bean cultivation after corn favors the occurrence of volunteer corn plants which interfere with the crop and cause yield losses of dry bean. Yield losses resulting from interferences caused by corn may be related to oxidative stress, which, in turn, is caused by the higher production of reactive oxygen species (ROS), such as hydrogen peroxide (H2O2). This work aimed to quantify H2O2 contents, and the activity of superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX) in dry beans under interference with densities of volunteer corn F2 originated from individual plants and clumps (seven corn plants emerged at the same point). Two experiments were carried out in a randomized blocks design with three replicates in Passo Fundo - RS, Brazil. Enzyme analysis was performed in a laboratory at 21, 35 and 46 days after dry bean emergence (DAE). Corn densities were 0, 0.5, 1, 2, 4, 8 and 12 plants or clumps m-2. The results show changes in H2O2 levels and in the activity of SOD, CAT, and APX enzymes with the increase of corn densities, in which the highest activity occurred for SOD. The interference of volunteer corn with dry beans alters the stress metabolism of dry bean but does not cause oxidative stress. The yield of dry beans reduced under interference with volunteer corn F2, but it is higher when the corn was originated from clumps.

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.…”

“…Despite documented alterations in oxidative stress and antioxidant systems, the literature remains divided on the response of crops to weed interference. In soybean and bean, Piasecki et al [ 13 , 14 ] showed that H 2 O 2 levels, APX, and CAT activity decreased with the increase in volunteer corn density, while SOD activity increased commensurate with weed density. Another study documented that the interference of wild poinsettia ( Euphorbia heterophylla ) on soybean did not result in any cellular damage or change in SOD, CAT, and APX enzyme activity in soybean [ 34 ].…”

“…After stress signals emanate from weed interferences, crop plants activate their antioxidant defense mechanisms that deal with ROS and restore cellular homeostasis [ 13 , 14 , 33 ]; these defenses certainly have energetic costs vis-à-vis yield. For example, soybean yield is decreased when volunteer maize is a competitor [ 13 ].…”

“…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 ].…”

“…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 ].…”