POSITIVE INFLUENCE OF ARBUSCULAR MYCORRHIZAL FUNGUS ON IN-VITRO RAISED HORTENSIA PLANTLETS

Micropropagated plantlets of hortensia (Hydrangea) var, leucht-feuer w ere inoculated with arbuscular mycorrhizal fungus Glomus intraradices Schenk and Smith, Roots were heavily mycorrhized at acclimatization st age. There was 100 per cent survival, shoot apices were active and no apparent ''transient transfer shock'' was noticed. Mycorrhized plants showed better growth, larger leaf area than the controls. 18 week old potted plants exhibited tremendous resistance towards induced stress e nvironmental conditions in the phytotron. In contrast, the non-mycorrh ized plants were severly wilted and produced reduced number of apical buds. It is postulated, there was benefits of early rejuvenation of na tural microflora on the sterile substratum which helped the plantlets in early acclimatization, fast establishment, enhanced growth and poss ibly improved root mycorrhization. The general bacterial population wa s several fold higher from the rhizospheres of the mycorrhized roots o ver the control. The dominating bacterium was Pseudomonas fluorescens biovar I.