Abstract: The effects of foliage application of lower, middle and higher concentration of CaCl₂(2.0, 4.0 and 8.0 g·L^-1) and NaCl (3.0, 6.0 and 9.0 g·L^-1) during fruit development on fruit pericarp microstructure of processing tomato ‘Ligeer 87-5’and ‘Shihong 12’were studied. The results showed that, for Ligeer 87-5, middle concentration of CaCl₂ significantly increased the cell layers of pericarp, different concentration of CaCl₂ and lower concentration of NaCl delayed the cell cavity enlargement by different degree, and lower and middle concentration of NaCl and CaCl₂ increased pericarp thickness and its outside cell wall thickness. For Shihong 12, higher concentration of CaCl₂ significantly increased the cell layers of pericarp, middle concentration of CaCl₂ increased the outside cell wall thickness of pericarp and delayed the cell cavity enlargement, lower concentration of NaCl delayed the cell cavity enlargement also, lower and middle concentration of NaCl and CaCl₂ increased pericarp thickness, and higher concentration of NaCl significantly decreased the outside cell wall thickness of pericarp but increased the number of vascular bundle of middle pericarp. In summary, foliage application of lower and middle concentration of NaCl and CaCl₂ during fruit development is thought practical to improve fruit pericarp structure which may benefit the transportation and storage of postharvest processing tomato.

Key words: processing tomato, pericarp, microstructure, exogenous calcium, exogenous sodium