title: Effect of simulated microgravitation on phytohormones and cell structure of tropical orchids.
abstract: When studying the effect of two month clinostating on the phytohormonal system of orchids with different types of shoot system branching and different shoot morphology, it was determined that, as a result of simulated microgravitation, endogenous growth regulators changed less in the species with sympodial branching than in species with monopodial branching and without pseudobulbs.  Stimulators prevail in the balance of growth regulators in species of the first type and inhibitors in species of the second type.  Besides this, comparative analysis of structural organization of juvenile leaf surface tissue of tested orchids was carried out.  Variability of size, number and structure of stomatal organization were found according to species belonging to each branching type after clinostating.  Electronic microscope studies show some structural peculiarities of epidermal and mesophilous cells.
authors.affiliation: N.N. Grishko Central Botanical Garden, National Ukraine Academy of Science, Kiev.
authors.forename: T
authors.initials: T
authors.lastname: Cherevchenko
authors.forename: N
authors.initials: N
authors.lastname: Zaimenko
authors.forename: T
authors.initials: T
authors.lastname: Majko
authors.forename: N
authors.initials: N
authors.lastname: Sytnjanskaja
mesh_terms: D005875:Gibberellins / Q000378:metabolism*; D006112:Gravitation; D007210:Indoleacetic Acids / Q000378:metabolism*; D008854:Microscopy, Electron; D010636:Phenols / Q000378:metabolism; D059828:Plant Cells; D018515:Plant Leaves / Q000502:physiology / Q000648:ultrastructure*; D018521:Plant Physiological Phenomena; D018520:Plant Shoots / Q000502:physiology*; D010944:Plants / Q000648:ultrastructure; D012399:Rotation; D018474:Weightlessness Simulation
chemical_list: D005875:Gibberellins; D007210:Indoleacetic Acids; D010636:Phenols