Rain-induced cracking severely limits production of many soft-textured, drupe, and berry fruits. Sweet cherry is a prominent example of the former ( Christensen, 1996 ). Cracking is commonly assumed to result from increased fruit turgor, caused by
Leaf cell turgor pressure is a water status variable related to firmness, growth, and with the consumer perception of wilting and freshness. Turgor pressure measurements are usually made at a laboratory using laborious procedures. With the
water content at the turgor loss point; RWC 0 , relative water content; RWC, relative water content at the turgor 1 0ss point; Ψ, water potential; Ψ π , osmotic potential; Ψ π 100 , osmotic potential at full turgor; Ψ π o , osmotic potential at the
). Cell turgor has a major function in determining tissue strength and changes in turgor are an integral part of fruit softening ( Harker et al., 1997 ). A positive relationship between cell turgor and tissue puncture firmness was observed using four
negative ψ Π at the stylar end, as compared with the stem end, would result in a higher turgor potential (ψ P ) at the stylar end, compared with the stem end. This could lead to a turgid stylar end and a flaccid stem end. The objective of this study was
humid conditions ( Knoche and Measham, 2016 ). A commonly cited model of rain cracking of soft and fleshy fruit is the critical turgor model originally proposed by Considine and Kriedemann (1972) for grape ( Vitis vinifera L.) berries. This concept
Maintenance of positive cell turgor is an essential factor in cell, and fruit, expansion. Since apple fruit partition carbohydrates between the starch and soluble pools to maintain turgor, variation among cultivars in this osmoregulatory aspect may play an important role in defining cultivar-specific fruit growth rates. Cultivar-specific apple fruit growth rates were determined over a 6 week period following June drop during 2 seasons. Fruit water relations parameters and carbohydrate levels were also measured. Although cultivar differences were evident, generally, fruit absolute growth rate increased, relative growth rate (RGR) declined, water potential and osmotic potential declined, and turgor potential increased as the season progressed. Soluble carbohydrate levels increased over 6 weeks, while starch levels fluctuated. Soluble carbohydrates contributed 50 to 90% of the osmotic potential. RGR was not correlated to either turgor potential or the relative allocation of carbohydrates between the soluble and starch pools. Thus, although positive turgor was maintained, factors other than turgor per se determine fruit growth rate.
, 1996 ). As with all materials, one would expect the mechanical properties of a fruit skin to be affected by temperature. The objectives of this study were to quantify the effects of 1) ripeness stage; 2) turgor, transpiration, and water uptake; and 3
Abstract
Water and turgor potentials of callus tissue from the cactus Echinopsis turbinata L. increased with increasing concentration of kinetin. Osmotic potential showed no consistent trend with an increase in concentration of kinetin or p-chlorophenoxyacetic acid (p-CPA).
The water potential (Ψ) of the sweet cherry fruit and its two components, osmotic potential (Ψ Π ) and turgor (Ψ P ) (where Ψ = Ψ Π + Ψ P ), are likely to be important factors affecting fruit cracking. First, fruit Ψ affects the rate of water