The lb23 mutant of recretohalophyte Limonium bicolor (Bag.) Kuntze with 20-, 24-, 28- and 32-cell salt glands shows elevated salt secretion

Abstract

Salt glands are specialized epidermal salt secretion structures on the surfaces of recretohalophytes leaves. In wild-type plants of the recretohalophyte Limonium bicolor (Bag.) Kuntze, salt glands comprise 16 cells each and appear as a blue ring under fluorescence microscopy, with four strong autofluorescence points. Here, we describe the lb23 mutant, which showed four additional types of salt glands, with five, six, seven and eight strong autofluorescence points. These salt glands comprised 20, 24, 28 and 32 cells, respectively, with correspondingly increased numbers of secretory, accessory, inner cup and outer cup cells. The cell arrangement and cell types within the salt glands in the mutant were unaltered from those of the wild type. For example, salt glands with five strong autofluorescence points had five secretory cells, five accessory cells, five inner cup cells and five outer cup cells. Compared with wild type, the abnormal salt glands with five, six, seven and eight strong autofluorescence points showed higher salt secretion rates per salt gland. Thus, the increase in salt gland cell numbers resulted in markedly increased salt secretion. This L. bicolor mutant provides an important resource for research on the molecular mechanism of salt gland development.