Seed Germination and Seedling Growth in Sopubia delphinifolia - a Hemi-root Parasite: Germination Requirements

Requirements for seed germination (emergence of radicle) and seedling formation (emergence of both radicle and cotyledons) of a hemi-root parasite Sopubia delphinifolia were studied in the absence of any host stimulus, in Petri dish and aseptic cultures. Both water washing in trickling tap water as well as cold treatment were effective in inducing/stimulating germination and seedling formation in the light. Although ethrel, an ethylene releasing compound, stimulated radicle emergence it inhibited the emergence of the cotyledons. Light was found to be essential for germination; none of the growth substances could replace the light requirement. Light responses seem to be mediated through the phytochrome system. The results indicate that the emergence of the radicle, its further growth into the root and the emergence of cotyledons are controlled by different factors.