Growth and Anatomical Parameters of Adventitious Roots Formed on Mung Bean Hypocotyls Are Correlated with Galactoglucomannan Oligosaccharides Structure

K Kollárová,D Lišková,P Capek,I Zelko,M Henselová

doi:10.1100/2012/797815

Abstract

The effect of galactoglucomannan oligosaccharides (GGMOs) compared with chemically modified oligosaccharides, GGMOs-g (with reduced number of D-galactose side chains) and GGMOs-r (with reduced reducing ends) on mung bean (Vigna radiata (L.) Wilczek) adventitious roots formation, elongation, and anatomical structure have been studied. All types of oligosaccharides influenced adventitious root formation in the same way: stimulation in the absence of exogenous auxin and inhibition in the presence of exogenous auxin. Both reactions are probably related with the presence/content of endogenous auxin in plant cuttings. However, the adventitious root length was inhibited by GGMOs both in the absence as well as in the presence of auxin (IBA or NAA), while GGMOs-g inhibition was significantly weaker compared with GGMOs. GGMOs-r were without significant difference on both processes, compared with GGMOs. GGMOs affected not only the adventitious root length but also their anatomy in dependence on the combination with certain type of auxin. The oligosaccharides influenced cortical cells division, which was reflected in the cortex area and in the root diameter. All processes followed were dependent on oligosaccharides chemical structure. The results suggest also that GGM-derived oligosaccharides may play an important role in adventitious roots elongation but not in their formation.

Highlights

The research in the recent years has focused on ascertainment of various plant growth regulators or some chemical products influence on growth and development of agricultural plants [1, 2]
Mung bean is in tropical countries a common and widely cultivated nutritious legume crop with antioxidant activity [3], seedlings of which have been used as a model to examine adventitious root formation [4, 5]
A pentasaccharide synthesized by Paris polyphylla var. yunnanensis showed a significant stimulus on tobacco seedling growth [15]

Summary

Introduction

The research in the recent years has focused on ascertainment of various plant growth regulators or some chemical products influence on growth and development of agricultural plants [1, 2]. Adventitious root formation is important for the vegetative propagation of plants and their growth. Various plant growth regulators have been tested for rooting of mung bean hypocotyl cuttings [5,6,7]. Oligosaccharides isolated from plant cell walls are the most important factors acting in plant growth and development [8]. Xylooligosaccharides stimulate, for example, the rooting of birch and black pine shoots [9] and induce callus formation and somatic embryogenesis in explants of common mallow (Malva silvestris L.) and cotton [10]. Oligogalacturonides support root elongation growth of lettuce [11] and were shown to promote cytokinin-induced vegetative shoot formation from tobacco leaf explants [12]. Yunnanensis stimulated shoot formation of P. polyphylla var. A pentasaccharide synthesized by Paris polyphylla var. yunnanensis showed a significant stimulus on tobacco seedling growth [15]

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