Studies of the Tomato in Relation to Its Storage: Ii. The Effects of Altered Internal Atmosphere Upon the Respiratory and Ripening Behaviour of Tomato Fruits Stored at 12.5 °c.

Abstract

When a mature green tomato fruit is stored at 12.5 °C. either with or without its stem, the expected respiratory climacteric accompanies the colour change associated with ripening. When the stem is removed and the stem scar area is covered carefully with hot paraffin wax, the fruit thereafter ripens slowly with a low, relatively constant rate of carbon dioxide output. These characteristics are ascribed to "auto-gas" storage resulting from restricted diffusion at the stem scar. The effect of waxing is reversible within limits since removal of the artificial seal after one month has resulted in a return to normal ripening and respiratory behaviour.When yellowing, yellow orange, and full red fruits are stored either with or without their stems, they complete in storage those phases of the respiratory climacteric that had not been completed before detachment from the plant. The careful waxing of fruits picked at these stages of maturity inhibits further coloration and reduces the rate of carbon dioxide output to the same extent as in fruits waxed at the mature green stage. The respiratory drift of fruits picked and stored unwaxed at the early "growing green" stage is characterized by two distinct peaks. Such fruits eventually ripen and the second peak is associated with the colour change that accompanies ripening. Similar fruits stored with stem scars waxed fail to ripen before their pathological "death" and their respiration rate is reduced by the waxing treatment.When yellowing and yellow-orange fruits are waxed, they become soft and highly susceptible to fungal attack before their ripening coloration has been completed. To inhibit the softening process in stored tomatoes, it thus appears to be necessary to apply wax before ripening has commenced. Unwaxed fruits become highly susceptible to fungal wastage only after attaining full ripeness. Waxed fruits on the other hand are subject to fungal wastage when green or partially coloured as well as when fully ripened. This is attributed to the progress of softening in the absence of the usual colour change associated with ripening. Waxing of the stem scars does not act as a deterrent to storage moulds at the waxed area. The waxed tomato has been found to be subject to several physiological disorders the symptoms of which are described.

Respiration & Internal Atmosphere of Avocado Fruit

“…Sealing the stem-end scar delayed ripening, demonstrating that the stem scar is an important route of gaseous exchange. Both observations suggest that the avocado skin is intermediate in its resistance between semipermeable peels such as those of the Granny Smith apple (22) and tomato (7), and permeable skins as in the case of Delicious apple (10). The site of resistance to gaseous exchange probably changed along with the ripening process.…”

“…Observations onl the epidermal layers as tlle tissue that offers nmajor resistance to gaseous (liffusioln ere nla(le b-TIrout et al (22) for the apple ali(l 1bv Cleil(leninillg (7) for the tomiiato. Biale (4) inlcl(le(I inlhis review-a brief accounit of the studies dealing witlh the internal atmospheres of fruits.…”

Role of internal atmosphere on fruit ripening and storability—a review

“…In tomato fruit, cuticle appeared to provide an excellent barrier (Thompson 2003) and as a result it may not contribute significantly for overall gaseous exchange across the fruit. However, instead of stomata, trichomes were observed on the surface of tomato fruits and trichome base cells are transformed into lenticels during maturation of the fruit (Clendenning 1941;Blanke 1986;Paul and Srivastava 2006). There are varietal differences in the number of trichomes, tendency of trichomes to get transformed into lenticels, density of lenticels and the dimension of stem scar portion of tomato fruits (Paul and Srivastava 2006).…”

Effects of Growth-regulating Substances on the Carbon Dioxide Evolution and Post-harvest Ripening of Tomatoes.

“…The other pattern, termed "anomalous," lacks the climacteric rise and shows instead a steady rate of respiration during the ripening period. The work of Clendenning (6,7) Fruits showing any indication of ripening were discarded at the beginning of the experiment and the remaining green fruits were divided into lots carefully matched as to size and, as far as possible, degree of maturity. The number of lots used varied with the experiment and depended upon the number of compounds and different concentrations of these compounds used in any one experiment.…”