Effect of Plant Density on the Growth of Seedlings of Seedlings of Spiranthes sinensis Ames and Liparis nervosa Lindl. in Symbiotic Culture

Abstract

Tne effect of plant density on the growth of seedlings of Spiranthes sinensis Ames and Liparis nervosa Lindl. in symbiotic cultures with Rhizoctonia isolates, effective for these orchids, was investigated using an oat medium containing the decoction of 25g/l oat grains and 1% agar. In high plant densitis, the weigth of individual seedlings increased in proportion to the quantity of medium per plant, but the rate of fresh weight increase was lowered with a decrease in plant density. The point where maximum fresh weight per individual seedling was obtained, i.e. the threshold where the density effect disappeared, was at a very low plant density: 60ml/plant for S. sinensis and 30ml/ plant for L. nervosa. The dry weight of mycelia per culturing flask also increased wich a decrease of plant density. It is considered that the effect of plant density on the growth of seedlings is, with respect to the oat medium, mainly dependent on the amounts of nutrients in the medium. Competition among aerial parts did not take part in the effect.