Abstract
•Shootlet morphology of Coccoloba uvifera was significantly improved by Polyethylene-glycol.•PEG at 200 mg L − 1 significantly increased the histochemical contents in leaves.•PEG-derived foliages exhibited improved anatomical features.•The treated plantlets showed improved survival under ex vitro conditions.
Coccoloba uvifera (L.) L. (sea grape) is a salt, drought, heat, and wind-tolerant plant species that stabilizes salty and sandy soils, and is used as a bio-wall and windbreaker in coastal landscapes. The natural population of C. uvifera in coastal areas is in peril due to anthropogenic and natural calamities. The impact of Polyethylene-glycol (PEG) on shootlet quality and foliar structural and histochemical traits of in vitro propagated plantlets of this halophytic tree species was investigated in this study. In vitro established shoots were subcultured on Murashige and Skoog's (MS) semisolid medium containing 1.0 mg L − 1 6-benzylaminopurine (BAP), 0.5 mg L − 1 of α-Naphthalene acetic acid (NAA), and PEG in various concentrations (100 - 500 mg L − 1). The cultures were maintained for 4 wk in a growth chamber under 16-h photoperiod at 25 ± 2 °C temperatures. Polyethylene-glycol (at 200 mg L − 1 in the medium) stimulated the healthy shoots proliferation in C. uvifera. Foliar transverse sections of the leaves derived from the most effective treatment exhibited well-differentiated cuticle, sclerenchyma, ground and vascular tissue systems, and histochemical traits such as polysaccharides (starch and mucilage), phenolic compounds (tannins, polyphenol, and lignin), cutin, and suberin as compared with the leaves grown in the control treatments. Thus, PEG is found to be a promising stress stimulator to improve foliar morpho-anatomy and histochemical accumulation, thereby promoting plantlets to withstand under ex vitro and in vivo stressful conditions.