Effect of ethyl methanesulfonate on growth and morphology of Doritis pulcherrima Lindl.

Abstract

Results showed that 0.5 mg/l BA and 1 mg/l NAA promoted the greatest seedling growth, with increased leaf number, leaf length, plant height, and root development. In the third experiment, protocorm-like bodies were treated with EMS at 0, 0.5, and 1.0% for 60 or 90 minutes. Survival declined with increasing concentration and time, with LD₅₀ values of 0.82% at 60 minutes and 0.54% at 90 minutes. Chlorophyll a, Chlorophyll b, and carotenoids were not significantly affected, but stomatal size changed. Stomatal width and length increased under 1.0% EMS, while density decreased from 220.17 to 149.47 stomata/mm². EMS treatment for 90 minutes showed an increased density relative to 60 min. RAPD analysis using 10 primers revealed high polymorphism indicating EMS induced genetic variation. Cluster analysis divided 22 samples into 9 groups at a similarity coefficient of 0.89, confirming genetic diversity despite no visible morphological changes.