Evaluation of Calcium Application Methods on Delaying Plant Wilting under Water Deficit in Bedding Plants

Floriculture crops can lose their aesthetic quality due to water deficit during postproduction. Calcium is a secondary messenger in plant stress signaling, and the treatment of calcium has been proposed to alleviate damage by various abiotic stresses. The objective of this research was to evaluate application methods of calcium to delay plant wilting under water deficiency in three species of bedding plants: viola (Viola cornuta), impatiens (Impatiens walleriana), and petunia (Petunia grandiflora). Three application methods were compared including spray, drench, and pre-drench. Calcium was applied as CaCl2 and Ca(NO3)2 at three concentrations ranging from 50 to 300 mM. The effect of calcium on shelf life was species-dependent, increasing shelf life in viola and impatiens, but not in petunia. Viola showed increased shelf life up to 154% and 400% in drench and pre-drench applications, respectively, compared to the control. In impatiens, spray and pre-drench applications delayed wilting symptoms by 53% and 200%, respectively. Comparing calcium sources, CaCl2 was the most effective as a drench, while Ca(NO3)2 pre-drench application effectively delayed wilting. There was no difference between CaCl2 and Ca(NO3)2 in spray application. These results provided the optimum application methods to delay plant witling and the potential of calcium application on enhancing water deficit tolerance in floriculture crops