Phenology and seed germination of the Indian Screw Tree Helicteres isora L. (Malvales: Malvaceae)

Abstract

Helicteres isora L. (Malvaceae), a medicinally important tree species used in Ayurveda as well as by folklore practitioners, is studied for its phenology, associated problems with the environment and anthropogenic effects. In Helicteres isora, flower buds are initiated by the end of July and flowering occurs during the middle of August to late October. Fruits mature during late January to early April. In between various factors like blister beetles, unidentified worms, deficit rainfall, early summer affect the flowering and seed setting, which cause 35–45 % loss. Seed viability of mature seeds were recorded 88.2% at fresh collection and decreases over period of time. In vitro, among the various treatments, acid treated seeds (H2SO4, 98.0%; 1 min) resulted in the best germination response of 84.5%. Sterile wet cotton soaked with sterile distilled water was found suitable for germination compared to other substratum, while half-strength MS medium with 2.0% sucrose was suitable for seedling development.

Keywords

• helicteres isora
• phenology
• seed germination.