Seed germination and seedling growth responses of Plectranthus amboinicus (Lour.) Spreng. to drought stress induced by polyethylene glycol

Abstract

Drought is an important factor that negatively affects plant growth. PEG-6000 was used to induce drought stress as it can modify the osmotic potential of nutrient solution cultures. Genus Plectranthus, from Lamiaceae family, is famous for its medicinal value and apart from its water conservation mechanism which was under wide cultivation in tropical countries including India. Intending to get insight into the polyethylene glycol induced drought stress responses, the present study focuses to evaluate the seed germination, seedling growth under stressed condition (Shoot length, Root length) and seedling fresh weight response of Plectranthus amboinicus (Lour.) Spreng. PEG 6000 applied with elevated concentrations (1, 5, 10, 15, 20, 25%) reduces the seed germination and seedling growth responses of Plectranthus amboinicus (Lour.) Spreng. in a concentration-dependent manner. Maximum inhibition of seed germination occurred at the Highest PEG concentration i.e. as for seed germination (28.3%), Root length (0.9 cm), shoot length (1.6 cm), seedling fresh weight (2.89 mg), seedling dry weight (0.11 mg) when compared with control values of respective trait as 89.44%, 2.1 cm, 2.5 cm, 8.42 mg and 0.35mg respectively.