Abstract
Two cultured cell lines were developed from cotyledons of a halophyte mangrove, Avicennia alba.In the high-Ca callus line, which was sub-cultured in amodified amino acid medium containing 3 mM CaCl2, growth of calluses and their protoplasts were both inhibited by low concentrations of CaCl2 in the culture medium. Removal of Ca2+ from the culture medium stimulated callus growth and the calluses could be sub-cultured without CaCl2 (low-Ca callus line). The intra- (cytoplasmic matrix and vacuole) and extra- (cell wall) cellular concentrations of elements, i.e., [Ca], [K], [Cl], [Na], [Mg], [P] and [S] were investigated using quantitative X-ray microanalysis of cryosections of calluses from bothcell lines. [Ca] was high in the cytoplasmic matrix and cell wall of the high-Ca line. [Ca] was lowered in the low-Calineinall cell compartments, though still detected. Ca-containing electron-dense precipitates were accumulated in the middle lamella of cell walls in resin-embedded sections of the high-Ca line. CaCl2 in the medium stimulated protoplast growth only in the low-Caline. These results suggested that a low cellular [Ca] is needed for protoplasts growth of A. alba. The importance of cellular [Ca] for the growth of halophilic mangrove plant cells was discussed.
Highlights
Mangrove plants grow in brackish waters in tropical and subtropical areas
We found that decrease of cellular Ca concentration ([Ca]) in the cytoplasmic matrix and vacuole was related to the halophilic nature of S. alba to Na+
To determine the cellular mechanisms underlying Ca2+ inhibition in callus culture of A. alba, we studied the ultrastructural features of cells, and intra- and extracellular [Ca] and concentrations of various elements, using electron probe X-ray microanalysis and compared the results with those of S. alba (Hayatsu, Ono, Hamamoto, & Suzuki, 2012; Hayatsu et al, 2014)
Summary
Mangrove plants grow in brackish waters in tropical and subtropical areas. More than 100 species of different families of trees and woody plants and ferns are included in mangrove plants (Tomlinson, 1986; Spalding, Kainuma, & Collins, 2010). A. alba suspension cells showed tolerance or halophilism to Na+, K+, Mg2+, Cl-, and SO42- ions; further addition of 10 mM of CaCl2, was inhibitory to growth (Hayashi et al, 2009), while S. alba suspension cells showed halophilic nature to all of the salts investigated including Ca2+ (Kawana & Sasamoto, 2008). This is likely through an increase of possible transport activities of Na+ from cytoplasmic matrix into the vacuoles under the stress of additional 50 mM NaCl in the medium This line of S. alba suspension culture was successfully sub-cultured in medium containing 50 mM NaCl. Here, we investigated the inhibitory effects of lower concentrations of CaCl2 on the growth of cotyledon-derived callus culture of A. alba which was newly induced in a mAA medium (Tsuchiya et al, 2013). The mechanisms underlying the tolerance to salts and halophilic nature of mangrove cells were discussed
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
