Tomato fruit continues growing while ripening, affecting cuticle properties and cracking

Abstract

Fruit cuticle composition and their mechanical performance have a special role during ripening because internal pressure is no longer sustained by the degraded cell walls of the pericarp but is directly transmitted to epidermis and cuticle which could eventually crack. We have studied fruit growth, cuticle modifications and its biomechanics, and fruit cracking in tomato; tomato has been considered a model system for studying fleshy fruit growth and ripening. Tomato fruit cracking is a major disorder that causes severe economic losses and, in cherry tomato, crack appearance is limited to the ripening process. As environmental conditions play a crucial role in fruit growing, ripening and cracking, we grow two cherry tomato cultivars in four conditions of radiation and relative humidity (RH). High RH and low radiation decreased the amount of cuticle and cuticle components accumulated. No effect of RH in cuticle biomechanics was detected. However, cracked fruits had a significantly less deformable (lower maximum strain) cuticle than non-cracked fruits. A significant and continuous fruit growth from mature green to overripe has been detected with special displacement sensors. This growth rate varied among genotypes, with cracking-sensitive genotypes showing higher growth rates than cracking-resistant ones. Environmental conditions modified this growth rate during ripening, with higher growing rates under high RH and radiation. These conditions corresponded to those that favored fruit cracking. Fruit growth rate during ripening, probably sustained by an internal turgor pressure, is a key parameter in fruit cracking, because fruits that ripened detached from the vine did not crack.

Effect of irrigation on yield parameters and antioxidant profiles of processing cherry tomato

“…Cherry tomato is more susceptible to cracking because crack appearance is limited to the ripening process and its fruit growth did not cease at the mature green stage, but continued until the overripe stage [35]. Our results demonstrate that supra-optimal water supply increased fruit weight causing fruit cracking of bigger fruits, which resulted in more non-marketable yield.…”

Transient Silencing of CHALCONE SYNTHASE during Fruit Ripening Modifies Tomato Epidermal Cells and Cuticle Properties

“…Also, a final increase in fruit size, mostly due to cell expansion, is detected between mature green and red ripe (Domínguez et al, 2008(Domínguez et al, , 2012, which leads to an increase in tangential width and a decrease in radial width of the epidermal cells (Domínguez et al, 2008;España et al, 2014). These final changes in the epidermis modified its shape, with cells from red ripe fruits being significantly more elongated than their mature green counterparts.…”

Transcriptional Activity of the MADS Box ARLEQUIN/TOMATO AGAMOUS-LIKE1 Gene Is Required for Cuticle Development of Tomato Fruit

“…Furthermore, the biochemical composition and mechanical performance of fruit cuticle seem to have a specific impact on the ripening process of this fleshy fruit species (Domínguez et al, 2012). It was reported that cuticles developed by TAGL1-silenced fruits showed alterations in their composition and biomechanical properties and that these changes are comprehensively associated with those affecting fruit development and ripening.…”

“…Therefore, the composition and mechanical performance of cuticle have been suggested to play important roles during fruit ripening (Domínguez et al, 2012). The cuticle is synthesized by the epidermal cell layer of the fruit pericarp.…”