PHYTOTOXIC EFFECTS OF Eucalyptus camaldulensis ON SOME SELECTED MONOCOT AND DICOT PLANT SPECIES

Abstract

The present study was conducted to investigate the phytotoxic effects of aqueous methanol extract on leaf and bark of Eucalyptus camaldulensis on germination and seedling growth of some selected monocot (foxtail millet and barnyard grass) and dicot (cauliflower, broccoli and tomato) plant species from June 2016 to June 2017. The aqueous methanol extract obtained from leaf and bark of eucalyptus followed six different concentrations ( T 0 = 0 g mL -1 , T 1 =0.001 g mL =0.003 g mL -1 , T 3 =0.01 g mL -1 , T 4 =0.3 g mL -1 , T 5 =0.1 g mL -1 ) were tested on five test species under laboratory condition. The aqueous extract obtained from leaf of eucalyptus were tested on five test species under net house at six different concentrations (T 0 = 0 ppm, T 1 =1 ppm, T 2 =2 ppm, T 3 =3 ppm, T =5 ppm ). Rsults revealed that a pronounced inhibitory effect of the aqueous and aqueous methanol leaf and bark extract of eucalyptus was observed on seed germination and seedling growth of five test plant species. The germination efficiency, plumule and radicle length and dry weight of plants were completely inhibited at the highest concentration of aqueous extracts (0.1g mL ) whereas least inhibition was observed at control at both laboratory and field condition. Maximum treatment effect was observed in germination and seedling growth of monocot plants (foxtail millet and barnyard grass) followed by three dicot plants (cauliflower, broccoli and tomato). Since foxtail millet and barnyard grass was mostly affected by different treatment effect, thus phytotoxic effect of eucalyptus may reduce weed competition with crops by affecting the germination and seedling growth of foxtail millet and barnyard grass. Therefore, it is possible to use these extracts as a component for production of bio-herbicides due to their phytotoxic effects on weeds and crops and considered as a natural way for sustainable weed management.