Mitigating effects of salicylic acid against herbicidal stress

Background, the context and purpose of the study: Pendimethalin [N-(1-ethyl propyl)-2, 6-dinitro-3, 4 xylidine] is one of the most commonly used herbicides. It induces harmful effect on non-target plants besides controlling the weed emergence. Salicylic acid (SA) plays an important role in abiotic stress tolerance. Present study was to assess the comparative efficacy of SA in combination with different concentrations of pendimethalin on black gram (Vigna mungo). The seeds of test plant were treated with field relevant concentrations (2, 5 and 10 ppm) of pendimethalin (P) and in combination with SA (0.5 mM) to observe effect of SA against herbicide toxicity. Experiment was performed in petri dish as well as in pot culture. The toxic effect of pendimethalin and SA on seed germination (SG), radicle length (RL) and mitotic index (MI) was evaluated in petri dish culture. Seedling height, pigments, protein, sugar contents and lipid peroxidation (LP) of 15 days old seedling were measured in pot culture. Total antioxidants (TA) were monitored as plant defence against oxidative stress. Results, the main findings: Results showed that SG and seedling growth of Vigna mungo decreased under P1, P2 and P3 treatments. RL and MI were also reduced significantly (p3 treatment. A slight increase of SG and seedling growth was observed in P2 treatment compared to P1. Herbicide treatment remarkably declined pigment, protein and sugar contents of the seedlings when compared with control. TA and malondialdehyde (MDA) content increase significantly under pendimethalin treated seedlings. Combined treatment (P+SA) elevated growth of the seedlings. As a consequence of herbicidal stress, SA enhanced SG, RL, MI, pigment, protein and sugar content significantly. Under combined treatments, LP and TA were decreased when compared with pendimethalin treatment. Conclusions, brief summary and potential implications: SA enhanced growth of Vigna mungo not only in combination with pendimethalin but also in treatment with SA alone as compared to control. Thus the results reveal, the role of SA in protection of Vigna mungo against herbicidal stress is apparent. The results are discussed in light of recent information.