Metabolomic and physico-chemical approach unravel dynamic regulation of calcium in sweet cherry fruit physiology.

Calcium (Ca) nutrition has a significant role in fruit physiology; however, the underlying mechanism is still unclear. In this study, fruit quality in response to CaCl, applied via foliar sprays (Ca) or/and hydro-cooling water (Ca), was characterized in 'Lapins' cherries at harvest, just after cold storage (20 days at 0 °C) as well as after cold storage followed by 2 days at 20 °C, herein defined as shelf-life period. Data indicated that pre- and post-harvest Ca applications increased total Ca and cell wall bound Ca, respectively. Treatment with Ca reduced cracking whereas Ca + Ca condition depressed stem browning. Both skin penetration and stem removal were affected by Ca feeding. Also, several color- and antioxidant-related parameters were induced by Ca treatments. Metabolomic analysis revealed significant alterations in primary metabolites among the Ca treatments, including sugars (eg., glucose, fructose), soluble alcohols (eg., arabitol, sorbitol), organic acids (eg.,malate, quinate) and amino acids (eg., glycine, beta-alanine). This work helps to improve our knowledge on the fruit's response to Ca nutrition.