Environmental and Physiological Studies on Fruit Growth and Mass Accumulation in Fruits of Tomato Plants

Abstract

Tomato (Lycopersicon esculentum Mill.) fruit production depends on the accumulation of mass (i.e., water, sugar, calcium ion, etc.) in the fruit via phloem and xylem transport. Water accumulation in the fruit is responsible for the fruit expansion growth, that is variable according to the balance between sap flux into the fruit via vascular system and transpiratory water loss from the fruit. Sugar accumulation in the fruit depends on translocation of photoassimilates from leaves through phloem. Salt or water stress treatment in the tomato fruit production is generally provided during the reproductive stage in order to obtain high quality fruits. This treatment leads to the increment of fruit sugar concentration, the restriction of fruit expansion growth and the increase in blossom-end rot. In a previous study on tomato fruit production, analyses of fruit parameters, such as dry matter weight, fresh weight, nutrients, etc., have been carried out using harvested fruits at the intervals of one week or 10 days. However, it is important to demonstrate the dynamics of sap flux with reference to mass accumulation in the fruit. Therefore, three new measurement systems or methods to evaluate the dynamics of mass accumulation in the fruit were developed, and the effects of day-night temperature, water stress, and salt stress on fruit growth and fruit water balance were analyzed.