NUTRITIONAL REQUIREMENTS FOR <em>IN</em> <em>VITRO</em> SEED GERMINATION OF 12 TERRESTRIAL, LITHOPHYTIC AND EPIPHYTIC ORCHIDS

Abstract

Nadarajan J, Wood S, Marks TR, Seaton PT & Pritchard HW. 2011. Nutritional requirements for
in vitro seed germination of 12 terrestrial, lithophytic and epiphytic orchids. Although numerous media have
been developed to evaluate both orchid seed germination and further seedling development after storage,
few studies have attempted to relate nutritional requirements to life history traits. For a range of terrestrial,
lithophytic and epiphytic orchid species, comparisons were made of germination on Knudson C, with and
without activated charcoal or banana powder, Norstog and Phytamax™ media to represent variations in
available nitrogen. Germination varied, with maximum values ranging from just 9% for Prosthechea cochleata,
Platanthera sp. and Spathoglottis paulinae to 95% for Phragmapedium longifolium. Along with Paphiopedilum
delenatii, Paphiopedilum philippinense and the epiphyte Guarianthe bowringiana, P. longifolium germinated well
on most media. Germination was significantly higher on Norstog than the other media for four of the six
epiphytes tested. Germination was maximum on Knudson C medium with activated charcoal for four of the six
terrestrial/lithophyte species. The results indicate a greater preference for nitrogen from amino acids rather
than ammonium or nitrate salts in seeds of epiphytes compared with some terrestrial orchid species.