Morphological Studies on Adventitious Root Formation in Cuttings

Abstract

Keeping the quantity of the endogenous growth substance in stem segments (4mm) of Portulaca grandiflora and Mesembryanthemum spectabile as less as possible, the experiment was carried out to test how morphologically the exogenously applied IAA, kinetin and their combination had effects on root formation, bud formation and callus formation.1. In M. spectabile, root formation and bud formation were promoted by IAA treatment under light codition. Root formation was inhibited by IAA treatment under dark condition, but bud formation was promoted by IAA treatment under dark condition.Root formation and bud formation were inhibited by kinetin treatment under light condition. Root formation was inhibited by kinetin treatment under dark condition, but bud formation was promoted by it under dark condition.In P. grandiflora, both root formation and bud formation were not affected by IAA treatment.2. In M. spectabile, a combination of IAA and kinetin showed more promotive effects on root formation, bud formation and callus formation than IAA or kinetin alone. Especially root formation was promoted by a combination of 10ppm IAA and 0.1-0.01ppm kinetin under light condition, and bud formation was promoted by a combination of 10ppm IAA and 1ppm kinetin under light condition.In P. grandiflora, root formation was promoted by a combination of 10ppm IAA and 1ppm kinetin under dark condition.3. Root formation in pith was promoted by a combination of 10ppm IAA and 0.1 ppm kinetin undr light condition.Bud formation of cortex was promoted by a combination of 1ppm IAA and 0.5ppm kinetin under light condition.4. Casein hydrolysate or Yeast extract put into the medium had not affects on both root formation and bud formation.