Response of Cell Division and Cell Expansion to Local Fruit Heating in Tomato Fruit

Abstract

<jats:p>To improve our understanding of fruit growth responses to temperature, it is important to analyze temperature effects on underlying fruit cellular processes. This study aimed at analyzing the response of tomato (<jats:italic>Solanum lycopersicum</jats:italic>) fruit size to heating as affected by changes in cell number and cell expansion in different directions. Individual trusses were enclosed into cuvettes and heating was applied either only during the first 7 days after anthesis (DAA), from 7 DAA until fruit maturity (breaker stage), or both. Fruit size and histological characteristics in the pericarp were measured. Heating fruit shortened fruit growth period and reduced final fruit size. Reduction in final fruit size of early-heated fruit was mainly associated with reduction in final pericarp cell volume. Early heating increased the number of cell layers in the pericarp but did not affect the total number of pericarp cells. These results indicate that in the tomato pericarp, periclinal cell divisions respond differently to temperature than anticlinal or randomly oriented cell divisions. Late heating only decreased pericarp thickness significantly. Continuously heating fruit reduced anticlinal cell expansion (direction perpendicular to fruit skin) more than periclinal cell expansion (direction parallel to fruit skin). This study emphasizes the need to measure cell expansion in more than one dimension in histological studies of fruit.</jats:p>

A multilevel analysis of fruit growth of two tomato cultivars in response to fruit temperature

“…A, C and Table ). Similar findings were also reported by Adams et al () and Fanwoua et al () in locally heated tomato fruits. The observed similarity in temperature response at the fruit level by ‘Brioso’ and ‘Cappricia’ in our study also corroborates the conclusion by Van Der Ploeg and Heuvelink () of limited variation in temperature response among tomato cultivars.…”

“…). In two separate experiments conducted with round tomato, Fanwoua et al () also observed that continuous fruit heating decreased pericarp cell volume in one experiment, while no significant effects were observed in the other. The observed tendency toward increase in mesocarp cell number at high temperature could be a result of shortening of the cell division cycle as also noted by Tardieu and Granier () in many plant species grown at high temperature.…”

“…The rectangular sections were made within the mesocarp and exocarp (first five top cell layers of the pericarp) separately. The endocarp and regions with vascular bundles in the mesocarp were not included in the counts as they were assumed not to have a significant contribution to pericarp volume (Fanwoua et al ). Mean periclinal cell diameter (Cd; direction parallel to fruit skin), cell volume (Cv), tissue volume (Tv) and number of cells (Cn) in pericarp tissue (mesocarp or exocarp) were then derived according to Eqns with the assumption that each cell is an ellipsoid. …”

“…However, under assimilate‐limiting conditions, these authors observed that fruit heating did not affect cell size but cell number decreased. In assimilate‐limited tomato fruits, fruit heating showed no significant effect on pericarp cell number, but resulted in a decrease in cell volume, fruit diameter and fresh weight (Fanwoua et al ).…”

Local Temperature Control in Greenhouse Vegetable Production

“…Therefore, higher fruit production can be expected by heating fruits locally in the cold (winter) season. Fanwoua et al (2012) enclosed trusses of tomatoes into cuvettes with heating from approximately 22/18°C (day/night) to 27/23°C and reported that heating the fruit shortened the fruit growth period and reduced the final fruit size due to a reduction in the final pericarp cell volume. Gautier et al (2005) tested fruit heating using 45°C water in flexible heating pipes circulating near growing cherry tomato fruits, and reported that the fresh weight, dry matter, and some secondary metabolites of the fruit were reduced.…”