Why do cherries crack

Fruit used for the cracking assays i. Fruit of uniform size and color without visible defects were selected at commercial maturity from a minimum of three trees per cultivar.

The silicone rubber was allowed to cure overnight. This procedure limited fruit water uptake to the skin surface only. Winkler, unpublished data. Unless otherwise specified, the intrinsic cracking susceptibility was determined as described by Weichert et al.

Briefly, two groups of 25 fruit each were incubated in deionized water. Fruit were removed from the water at regular intervals and checked for macroscopically visible skin cracks. Cracked fruits were removed and noncracked fruits were reincubated in water. Water uptake was determined gravimetrically in a separate experiment on fruit from the same batch. Fruits were weighed, incubated in deionized water, removed after 45 and 90 min, blotted with tissue paper, reweighed, and reincubated.

The rate of water uptake was calculated on an individual fruit basis as the slope of a linear regression fitted through a plot of cumulative fruit mass vs. The number of individual fruit replicates was The needle was positioned such that the tip was close to the pit on the cheek of the fruit.

The custom built perfusor comprised a total of 30 disposable syringes connected via rigid polytetrafluoroethylene tubing to the hypodermic needles inserted in the fruit. The rate of perfusion was Fruit was perfused at ambient temperature up to the point of cracking.

At this time, the volume injected into the fruit was read from the syringe. Cracking was assessed by visual inspection. For data analysis, the cumulative frequency of the number of fruit cracked was plotted against cumulative water uptake. This relationship follows a sigmoidal pattern. A logistic regression model was fitted and the WU 50 calculated as the x coordinate at the point of inflection. In the immersion assay, the rate of water uptake and the time course of cracking were determined and the T 50 and WU 50 calculated as described earlier.

The minimum number of replications for the perfusion test was Microcracks were induced by incubating fruit for 24 h in isotonic PEG solution. Incubating fruit in isotonic PEG increases the frequency of microcracks in the strained sweet cherry cuticle Knoche and Peschel, Thereafter, the time course of cracking following incubation in water, the rate of water uptake, and cracking following perfusion was determined as described earlier.

Fruit not incubated in PEG served as control. The minimum number of replicates for the perfusion test was The minimum number of replicates was For comparison, the WU 50 was determined on fruit from the same batch following incubation. Time courses of cracking and water uptake were established and the T 50 and WU 50 calculated. Skin defects were simulated by manually puncturing the fruit skin in the cheek region using a double-edged blade.

Depth and width of the cuts were 0. Fruit having an intact skin served as control. Subsequently, water uptake and cracking were determined and the T 50 and WU 50 calculated as described earlier. Unabraded fruit served as control. The amounts of water transpired were determined gravimetrically. Thereafter, the time course of cracking and water uptake were quantified and the T 50 and WU 50 calculated. The net change in mass was quantified gravimetrically. Cracking was determined by regular visual inspection and the T 50 and WU 50 calculated.

The number of replicates was Where error bars are not visible in a graph, they are smaller than the plotting symbols or data for individual fruit are shown Fig. Regression analysis was conducted using R version 3. A Time course of water uptake inset and cracking when incubating sweet cherry fruit in deionized water main graph. B Cracking as a function of the amount of water perfused into fruit of the same batch.

Dashed line in B represents the sigmoidal regression line from A redrawn on the x axis scale of B. Incubating sweet cherry fruit in water resulted in rapid fruit cracking.

By 48 h of incubation, most fruit had cracked Fig. When expressed as the percentage increase in mass the WU 50 averaged 1. There was no correlation between either the T 50 , the WU 50 , or the percentage increase in mass and the rate of water uptake Fig. A Time course of cracking of sweet cherry fruit. Data points represent fruit from 19 cultivars. B Cracking of sweet cherry fruit expressed as a function of water uptake. Data symbols represent individual sweet cherry cultivars.

For an individual genotype, cracking often followed a sigmoidal pattern with time and at a constant rate of uptake also with the amount of water taken up Fig. After 6 h and mg of water uptake all fruit had cracked Fig. When fruit from the same batch was perfused with water, the percentage of cracked fruit also increased in a sigmoidal pattern with water uptake.

The WU 50 on perfusion, however, was Pretreating fruit by incubation in isotonic PEG for 24 h resulted in an increased rate of water uptake during subsequent incubation in water as compared with fruit without such pretreatment Table 1. There was only a marginal effect on the WU 50 in perfusion when fruit were pretreated by incubation in isotonic PEG Table 1.

Effect of water uptake on cracking of sweet cherry fruit. Water uptake occurred via the surface during immersion of whole fruit or by perfusion through a hypodermic needle inserted into the fruit. To assess the role of microcracks, fruits were preincubated for 24 h in isotonic polyethylene glycol PEG solution before immersion.

Fruit without preincubation served as control. The difference between the WU 50 determined in the incubation and perfusion assays was not related to the presence of water on the surface Table 2.

When the fruit surface was wetted during perfusion, the WU 50 was almost identical to that when dry fruit were perfused Table 2. Again, the WU 50 was markedly higher in perfusion than in immersion assays.

Water uptake occurred by perfusion through a hypodermic needle inserted into the fruit. To assess the effect of surface wetness during perfusion, fruit was held with a dry surface in the ambient atmosphere or incubated in isotonic polyethylene glycol PEG solution.

Fruit incubated in deionized water in a classical immersion assay served as control. We shall therefore concentrate on water influx. It has been shown that the rate of water import is related more closely to cracking than the total amount of water accumulated. Fruits from varieties that have a slow rate of water uptake, take much more time to accumulate damaging quantities of water than cracking sensitive varieties with a fast rate of water uptake. This could be the reason that the former varieties are less susceptible to cracking.

There is a close negative relationship between osmotic potential and susceptibility to cracking, which appears to be an important factor associated with differences in cracking between varieties. There are no indications that differences in fruit size or firmness are involved in variety differences.

In summary, a range of factors is involved in fruit cracking and differences in one or more of these factors among and within varieties might explain the variation in occurrence of cracking, even between fruits on a single tree. From the above it is clear that water is involved in cracking. Although it is common knowledge that rain can induce splitting in nearly mature or mature stone fruits, it is impossible to conclude whether it is the water import into the fruit through the skin, the stem or both, that are the cause of splitting.

It has been reported that stem-end splits occurred immediately after irrigation under moisture stress. On trees that were adequately irrigated throughout the season, very little splitting was observed.

This indicates, that water entering the fruit solely through the stem is sufficient to cause splitting. We know that fruit cracking is related to fruit turgor, which typically peaks in the early morning hours and is influenced by irrigation amounts and frequency. When previously water-stressed trees are irrigated, the overall recovery in water potential and the subsequent movement of solutes to the calyx end of the fruit, resulted in excessive turgor pressures in this region, leading to stem-end splitting.

Fruits from well-watered trees or from continuously droughted trees, did not show such changes and defects. Cracking in cherries. Determination of cracking susceptibility.

Acta Agric Scand. Vascular flow of water induces side cracking in sweet cherry Prunus avium L. Accessed 27 Sept Two-dimensional tension tests in plant biomechanics—sweet cherry fruit skin as a model system. Plant Biol. Cuticular properties and postharvest calcium applications influence cracking of sweet cherries. Weichert H, Knoche M. Studies on water transport through the sweet cherry fruit surface. FeCl3 decreases water permeability of polar pathways. J Agric Food Chem [Internet]. Is there a relation between changes in osmolarity of cherry fruit flesh or skin and fruit cracking susceptibility?

American Society for Horticultural Science; ;— Accessed 14 Oct Association between the concentration of n-alkanes and tolerance to cracking in commercial varieties of sweet cherry fruits. Sci Hortic. An integrated metabolomic and gene expression analysis identifies heat and calcium metabolic networks underlying postharvest sweet cherry fruit senescence.

Metabolomic and physico-chemical approach unravel dynamic regulation of calcium in sweet cherry fruit physiology. Plant Physiol Biochem. Postharvest responses of sweet cherry fruit and stem tissues revealed by metabolomic profiling. Metabolic features underlying the response of sweet cherry fruit to postharvest UV-C irradiation. Decision tree supported substructure prediction of metabolites from GC-MS profiles. Metabolic mechanisms underpinning vegetative bud dormancy release and shoot development in sweet cherry.

Environ Exp Bot. A versatile targeted metabolomics method for the rapid quantification of multiple classes of phenolics in fruits and beverages. J Agric Food Chem. Monochromatic light increases anthocyanin content during fruit development in bilberry.

BMC Plant Biol. Khadivi-Khub A. Physiological and genetic factors influencing fruit cracking. Acta Physiol Plant. Sansavini S, Lugli S. Sweet cherry breeding programs in Europe and Asia. Acta Hortic. Incidence and type of cracking in sweet cherry Prunus avium L. Crop Pasture Sci [Internet]. Changes in strain and deposition of cuticle in developing sweet cherry fruit. Physiol Plant.

Wang Y, Long LE. Physiological and biochemical changes relating to postharvest splitting of sweet cherries affected by calcium application in hydrocooling water. Food Chem [Internet]. Elsevier; ;—7. Accessed 9 July Peschel S, Knoche M. Studies on water transport through the sweet cherry fruit surface: XII. J Am Soc Hortic Sci. Trehalose and plant stress responses: Friend or foe? Trends Plant Sci [Internet]. Elsevier Current Trends; ;— Accessed 12 June Fine tuning of trehalose biosynthesis and hydrolysis as novel tools for the generation of abiotic stress tolerant plants.

Front Plant Sci [Internet]. Frontiers; ; Transcriptome analysis of atemoya pericarp elucidates the role of polysaccharide metabolism in fruit ripening and cracking after harvest.

BioMed Central; ; Accessed 13 June Sweet cherry fruit: ideal osmometers? Front Plant Sci. Bio-protective effects of homologous disaccharides on biological macromolecules. Eur Biophys J. Cold-induced repression of the rice anther-specific cell wall invertase gene OSINV4 is correlated with sucrose accumulation and pollen sterility.

Plant, Cell Environ. Mohnen D. Pectin structure and biosynthesis. Curr Opin Plant Biol. Andrews PK, Li S. Transcriptional analysis of cell wall and cuticle related genes during fruit development of two sweet cherry cultivars with contrasting levels of cracking tolerance. Chil J Agric Res [Internet]. Evolving views of pectin biosynthesis. Annu Rev Plant Biol [Internet]. Metabolic click-labeling with a fucose analog reveals pectin delivery, architecture, and dynamics in Arabidopsis cell walls.

Organisation of the pantothenate vitamin B5 biosynthesis pathway in higher plants. Plant J. Biological functions of asparagine synthetase in plants. Plant Sci [Internet].

Elsevier; ;— Expansion of the cherry puts a strain on the cuticle, and as the strain increases, the number of microscopic cracks also increases, providing openings for more water uptake. When the fruit surface is wet, the cell walls soften and the number of microscopic cracks further increases. High humidity can also lead to more cracking.

Knoche estimated that 30 to 50 percent of water uptake occurs along the stem-fruit juncture, either through a leaky stem or skin cracks, and the rest through the fruit surface. The amount of water taken up depends on the fruit surface area meaning the size of the cherry , its permeability, and the driving force gradient in water potential. Although water can move either in or out of the cherry skin, about 14 times more water goes in than moves out via transpiration.

Knoche said knowing how the skin cracks will be useful in finding mechanisms to reduce splitting. Strategies might be to reduce the strain on the cuticle, keep the fruit surface dry, and reduce its permeability.