Morphological and Metabolic Changes in Soybean Plants Cultivated in Irrigated Rice Rotation and as Affected by Imazapyr and Imazapic Herbicides Carryover

Abstract

The appearance of soybean cultivars that are tolerant to herbicides from the imidazolinone group enables irrigated rice rotation conducted on Clearfield® system. The objective of this work was to evaluate the morphological and metabolic changes of soybean cultivars containing Cultivance® (CV), which is tolerant to imidazolinone, sulphonylurea toletant (STS) and Roundup Ready® (RR), which is tolerant to glyphosate as affected by carryover of increasing doses of imazapyr and imazapic herbicides mixture, applied in the management of irrigated rice crop. Thus, experiments were conducted on the field and in greenhouse, evaluating phytotoxicity, height, leaf area, shoot dry matter, as well as variables related to the secondary metabolism of plants like chlorophyll, carotenoids, hydrogen peroxide, lipid peroxidation and electrolytes leakage. Soybean cultivars RR and STS are susceptibles to the carryover of imazapyr and imazapic mixture applied in the management of irrigated rice crop, whereas the CV cultivar is resistant. The rise in the herbicide carryover dose increases the reactive oxygen species (ROS) production in soybean plants. The RR cultivar, in general, shows higher ROS production compared to the other soybean cultivars.

Physiological and productive traits of soybean with metsulfuron-methyl application at early desiccation

“…The impairment of PSII affects the ETR and the production of adenosine triphosphate and nicotinamide adenine dinucleotide phosphate necessary for Calvin cycle functioning and CO 2 fixation (Timm et al, 2016). Fraga et al (2019) also found an increase in lipid peroxidation in soybean leaves, which could cause oxidative stress and the degradation of the ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) enzyme, which fixes atmospheric carbon dioxide within photosynthesis (Das et al, 2016). Nonphotochemical quenching was greater at 0 DBS than at the lowest application rates.…”

“…a lower photochemical dissipation may be associated with a closed proportion of PSII reaction centers, that is, with an increase in the proportion of the reduced state of quinone A and a decrease in the excitation energy available for photochemical processes (Genty et al, 1989). In addition, the reaction centers are constituted by chlorophylls, which have already been reported as being reduced in soybean plants exposed to the carryover of imazapyr + imazapic, both ALSinhibiting herbicides (Fraga et al, 2019). Even at 45 DBS, a reduction in ETR was observed at rates higher than 3.6 g ha -1 (Figure 3 C and Table 3).…”

“…The occurrence of phytotoxicity was modeled according to the soybean sowing interval after the application of metsulfuron-methyl at different rates, and a response surface was evaluated over time in DAE, in the two crop years (Figure 2 and Table 1). Metsulfuron-methyl is active at very low concentrations and is characterized as slow acting, with a carryover potential that depends on the class and rate of the used herbicide, sensitivity of the crop in succession, soil characteristics, and environmental conditions before and after herbicide application (Ismail & Azlizan, 2002;Santos et al, 2016;Gonçalves et al, 2018;Fraga et al, 2019).…”

Imidazolinone herbicide dissipation in rice fields as affected by intermittent and continuous irrigation

“…Also, resistant cultivars could maintain yield in places with residual herbicide (Agostinetto et al, 2018). Soybean cultivars that were affected by the herbicide carryover have higher production of reactive oxygen species (ROS) and, consequently, greater plant damages (Fraga et al, 2019).…”

Water balance for determination of excess water in soybean cultivated in lowland soils

“…High demand for vegetable protein and favorable economic condition enables the expansion of soybean cultivation in areas that were not traditionally cultivated, i.e., the lowland areas in southern Brazil (Rocha et al, 2017;Sartori et al, 2016), entailing 1/3 of the area traditionally sown with irrigated rice (IRGA, 2019). In addition, crop rotation is an alternative to control weed infestations (Scherner et al, 2018;Fraga et al, 2019), break pest and disease cycles, improve soil conditions for plant development and increase the sustainability of the system (Goulart et al, 2020) Imperfectly drained soils (Planosols) predominate in these areas due to the water table being close to the surface (Streck et al, 2008). In areas cultivated with irrigated rice, the superficial layers undergo disruption and compaction due to mechanized operations used for rice cultivation, which usually take place under soaked soil conditions and reduce the water infiltration rate (Sartori et al, 2016).…”