Toxicity Assessment of Herbicides Quizalafop-p-Ethyl and Clodinafop Towards Rhizobium Pea Symbiosis

Abstract

In modern conventional agriculture, herbicides are frequently used to prevent yield losses due to weeds. Herbicides also affect negatively the productivity of legumes. With these considerations, we evaluated the effects of soil applications of different concentrations of quizalafop-p-ethyl and clodinafop on the performance of Rhizobium inoculated pea, grown in clay pots. In this study, the concentration of herbicides higher than the recommended rates of quizalafop-p-ethyl and clodinafop adversely affected the dry matter accumulation, symbiotic properties, grain yield and nutrient status of pea plants. Toxicity of quizalafop-p-ethyl and clodinafop to pea plants increased progressively with increase in rates of herbicides. Of the two herbicides, quizalafop-p-ethyl was more toxic than clodinafop. In contrast, when herbicide tolerant Rhizobium strain MRP1 was also used with herbicide, it increased the measured parameters at all concentrations. A maximum increase of 11%, 17%, 46%, 33%, 21% and 7% in the root N, shoot N, root P, shoot P, seed yield and seed protein, respectively, was observed when MRP1 was used with 120 microg quizalafop-p-ethyl kg(-1) soil while with 1,200 microg clodinafop kg(-1) soil it increased the root N, shoot N, root P, shoot P, seed yield and seed protein by 20%, 9%, 56%, 56%, 29% and 7%, respectively, compared with the un-inoculated but herbicide treated control. This study suggested that the toxic effects of herbicides on pea plants could be attenuated by applying growth promoting herbicide tolerant strain of Rhizobium under herbicide stressed soil environment.

Effect of rhizosphere bacteria on antioxidant enzymes and some biochemical characteristics of Medicago sativa L. subjected to herbicide stress

“…According to Ahemad and Khan, although consuming Quizalafop-p-Ethyl and Clodinafop herbicides led to decrease in chickpea growth, the plants inoculated with Mesorhizobium sp. MRC4 had more yields (Ahemad and Khan 2009). Ma et al assessed the improvement in Brassica juncea growth and nickel tolerance by nickel resistant-plant-growth-promoting bacteria (Ma et al 2009).…”

Perspective of beneficial microbes in agriculture under changing climatic scenario: a review

“…This bacterium is known to increase the symbiotic properties of plants like nodulation and leghaemoglobin content, enhancement of nitrogen and phosphorous uptake, seed yield and seed protein Ahemad and Khan, 2011a;Ahemad and Khan, 2010;Ahemad and Khan, 2009 Bacillus weihenstephanensis strain SM3…”

Insecticide‐tolerant and plant‐growth‐promoting Rhizobium improves the growth of lentil (Lens esculentus) in insecticide‐stressed soils

“…In this context, inoculation of compatible and appropriate rhizobia with legumes under field conditions has been successful in many countries. In addition to N 2 fixation, rhizobia are also reported to degrade toxic pesticides to non‐toxic forms,6 synthesise antifungal compounds,7 phytohormones and siderophores8, 9 and solubilise insoluble phosphate 7. Therefore, identifying rhizobia possessing multiple growth‐promoting activities and exhibiting insecticide tolerance ability will be useful in optimising the yields of grain legumes in both conventional and stressed production systems.…”