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 (p<0.05) in treatments with herbicide and reduction
was more pronounced in 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.
Key
words: Lipid peroxidation / Mitotic index / Pendimethalin / Total
antioxidant / Vigna mungo
