scholarly journals Mottling on Sweet Cherry Fruit Is Caused by Exocarp Strain

2013 ◽  
Vol 138 (1) ◽  
pp. 18-23 ◽  
Author(s):  
Eckhard Grimm ◽  
Stefanie Peschel ◽  
Moritz Knoche

Mottling (pale spots) is clearly visible to the naked eye in all regions of the surface in all except for yellow cultivars of sweet cherry fruit (Prunus avium L.). The objective was to characterize these spots and their distribution on the exocarp. Within the spots, anthocyanins were limited to the epidermal cell layer but, in areas immediately adjacent to the spots, anthocyanins were present in the epidermal and in the hypodermal cell layers (making these areas darker). In ‘Sam’ sweet cherries, the median length and width of a spot in the cheek region were 390 and 162 μm, respectively, and the median area was 0.053 mm2 per spot. The spatial density in the cheek region averaged 1.94 (± 0.13) spots per mm2 and the percentage of surface area covered by the spots was 12.5% (± 1.07%). Epidermal cells within a spot had slightly larger projected surface areas than those in the adjacent region and thicker cell walls. The margins of the spots did not align with the anticlinal walls of the epidermal cells. The spots’ long axes were oriented parallel with the stem/stylar scar axis, whereas the slightly elongated epidermal cells within and adjacent to the spots were orientated perpendicular to the stem/stylar scar axis. The spatial density of spots and the cumulative spot area were highest in the region of the stylar scar, intermediate in the cheek and stem cavity, and lowest in the suture region. Spot spatial density on small fruit exceeded that on larger fruit, but the areas of individual spots was smaller. When an exocarp segment was excised from the cheek of a fruit, it contracted slightly as elastic strain was released. The projected surface area of the spots and that of the whole segment decreased to a similar extent. Our data suggest that spots result from a tensional failure during Stage III development in which the anthocyanin-containing hypodermal cell layer tears (schizogenously) and separates from the epidermis. This being the case, the pale spots (mottling) can be referred to as “strain spots.”

2005 ◽  
Vol 130 (4) ◽  
pp. 487-495 ◽  
Author(s):  
Stefanie Peschel ◽  
Moritz Knoche

Frequency and distribution of microcracks in the cuticular membrane (CM) were monitored in cheek, suture, pedicel cavity and stylar regions of developing sweet cherry (Prunus avium L.) fruit using fluorescence microscopy following infiltration with a fluorescence tracer (1 to 2 min in 0.1% w/v acridine orange containing 50 mm citric acid and 0.1% Silwet L-77, pH 6.5). These microcracks were limited to the cuticle, did not extend into the pericarp and were only detected by microscopy. Fruit mass and surface area increased in a sigmoidal pattern with time between 16 days after full bloom (DAFB) and maturity. The increase in frequency of fruit with microcracks paralleled the increase in fruit mass. During early development (up to 43 DAFB) the CM of `Sam' fruit remained intact. However, by 57 DAFB essentially all `Sam' fruit had microcracks in the pedicel cavity and ≈25% in the suture region with little change thereafter. At maturity percentage of `Sam' fruit with microcracks in cheek, suture, pedicel cavity and stylar end region averaged 23%, 25%, 100%, and 63%, respectively. Similar data were obtained for `Hedelfinger' (70% and 100% for cheek and pedicel cavity, respectively), `Kordia' (80% and 100%) and `Van' (100% and 100%). Generally, microcracks were most severe in pedicel cavity and stylar end region. Most of the first detectable microcracks formed above periclinal walls of epidermal cells perpendicular to their longest axis (72% and 92% in cheek and stylar regions, respectively). The other microcracks formed above the anticlinal walls were mostly oriented in the direction of the underlying cell wall. There was no difference in projected surface area, length/width ratio or orientation among epidermal cells below, adjacent to or distant from the first detectable microcracks in the CM. However, as length of microcracks increased the projected surface area of cells underlying cracks increased suggesting strain induced upon cracking of the CM. Permeability of excised exocarp segments in osmotic water uptake was positively correlated with number of stomata and number of microcracks in the CM. From our results we suggest that strain of the epidermal system during stage III of fruit growth is a factor in “microcracking” of the CM that may predispose fruit to subsequent rain-induced cracking.


Development ◽  
1996 ◽  
Vol 122 (11) ◽  
pp. 3433-3441 ◽  
Author(s):  
M.C. Perbal ◽  
G. Haughn ◽  
H. Saedler ◽  
Z. Schwarz-Sommer

In Antirrhinum majus, petal and stamen organ identity is controlled by two MADS-box transcription factors, DEFICIENS and GLOBOSA. Mutations in either of these genes result in the replacement of petals by sepaloid organs and stamens by carpelloid organs. Somatically stable def and glo periclinal chimeras, generated by transposon excision events, were used to study the non-cell-autonomous functions of these two MADS-box proteins. Two morphologically distinct types of chimeras were analysed using genetic, morphological and molecular techniques. Restoration of DEF expression in the L1 cell layer results in the reestablishment of DEF and GLO functions in L1-derived cells only; inner layer cells retain their mutant sepaloid features. Nevertheless, this activity is sufficient to allow the expansion of petal lobes, highlighting the role of DEF in the stimulation of cell proliferation and/or cell shape and elongation when expressed in the L1 layer. Establishment of DEF or GLO expression in L2 and L3 cell layers is accompanied by the recovery of petaloid identity of the epidermal cells but it is insufficient to allow petal lobe expansion. We show by in situ immunolocalisation that the non-cell-autonomy is due to direct trafficking of DEF and GLO proteins from the inner layer to the epidermal cells. At least for DEF, this movement appears to be polar since DEF acts cell-autonomously when expressed in the L1 cell layer. Furthermore, the petaloid revertant sectors observed on second whorl mutant organs and the mutant margins of petals of L2L3 chimeras suggest that DEF and GLO intradermal movement is limited. This restriction may reflect the difference in the regulation of primary plasmodesmata connecting cells from the same layer and secondary plasmodesmata connecting cells from different layers. We propose that control of intradermal trafficking of DEF and GLO could play a role in maintaining of the boundaries of their expression domains.


2016 ◽  
Vol 141 (1) ◽  
pp. 45-53 ◽  
Author(s):  
Martin Brüggenwirth ◽  
Moritz Knoche

The skins of all fruit types are subject to sustained biaxial strain during the entire period of their growth. In sweet cherry (Prunus avium L.), failure of the skin greatly affects fruit quality. Mechanical properties were determined using a biaxial bulging test. The factors considered were the following: ripening, fruit water relations (including turgor, transpiration, and water uptake), and temperature. Excised discs of fruit skin were mounted in a custom elastometer and pressurized from their anatomically inner surfaces. This caused the skin disc to bulge outwards, stretching it biaxially, and increasing its surface area. Pressure (p) and biaxial strain (ε) due to bulging were quantified and the modulus of elasticity [E (synonyms elastic modulus, Young’s modulus)] was calculated. In a typical test, ε increased linearly with p until the skin fractured at pfracture and εfracture. Stiffness of the skin decreased in ripening late stage III fruit as indicated by a decrease in E. The value of pfracture also decreased, whereas that of εfracture remained about constant. Destroying cell turgor decreased E and pfracture relative to the turgescent control. The E value also decreased with increasing transpiration, while pfracture and (especially) εfracture increased. Water uptake had little effect on E, whereas εfracture and pfracture decreased slightly. Increasing temperature decreased E and pfracture, but had no effect on εfracture. Only the instantaneous elastic strain and the creep strain increased significantly at the highest temperatures. A decrease in E indicates decreasing skin stiffness that is probably the result of enzymatic softening of the cell walls of the skin in the ripening fruit, of relaxation of the cell walls on eliminating or decreasing turgor by transpiration and, possibly, of a decreasing viscosity of the pectin middle lamellae at higher temperatures. The effects are consistent with the conclusion that the epidermal and hypodermal cell layers represent the structural “backbone” of the sweet cherry fruit skin.


HortScience ◽  
2003 ◽  
Vol 38 (7) ◽  
pp. 1410-1413 ◽  
Author(s):  
Martin Harz ◽  
Moritz Knoche ◽  
Martin J. Bukovac

Water conductance of the cuticle of mature fruit of apple [Malus sylvestris (L.) Mill. var. domestica (Borkh.) Mansf., `Golden Delicious' Reinders/`Malling 9' (M.9)], sweet cherry (Prunus avium L., `Sam'/`Alkavo'), grape (Vitis vinifera L.), pepper (Capsicum annuum L. var. annuum Fasciculatum Group, `Jive'), and tomato (Lycopersicon esculentum Mill.) was de ter mined using excised epidermal segments (consisting of epidermis, hypodermis, and some cell layers of parenchyma) and enzymatically isolated cuticular membranes (CM) from the same sample of fruit. Segments or CM were mounted in diffusion cells and transpiration was monitored gravimetrically. Conductance (m·s-1) was calculated by dividing the flux of water per unit segment or CM area (kg·m-2·s-1) by the difference in water vapor concentration (kg·m-3) across segments or CM. Transpiration through segments and through CM increased with time. Conductance of segments was consistently lower than that of newly isolated CM (3 days or less). Conductance decreased with increasing time after isolation for apple, grape, or sweet cherry CM, and for sweet cherry CM with increasing temperature during storage (5 to 33 °C for 4 days). There was no significant effect of duration of storage of CM on conductance in pepper or tomato fruit. Following storage of CM for more than 30 days, differences in conductance between isolated CM and excised segments decreased in apple, grape, and sweet cherry, but not in pepper or tomato. Use of metabolic inhibitors (1 mm NaN3 or 0.1 mm CCCP), or pretreatment of segments by freezing (-19 °C for 18 hours), or vacuum infiltration with water, had no effect on conductance of apple fruit segments. Our results suggest that living cells present on excised segments do not affect conductance and that epidermal segments provide a useful model system for quantifying conductance without the need for isolating the CM. Chemical names used: sodium azide (NaN3); carbonylcyanide m-chlorophenylhydrazone (CCCP).


2015 ◽  
Vol 140 (5) ◽  
pp. 472-479 ◽  
Author(s):  
Eckhard Grimm ◽  
Moritz Knoche

The skin is the primary load-bearing structure in a sweet cherry fruit (Prunus avium L.). Failure of the skin in rain cracking is considered to be related to water uptake. Little is known of the skin’s water potential, its osmotic potential (ΨΠS), and turgor. The objective here was to quantify ΨΠS relative to the osmotic potential of the flesh (ΨΠF). Spatial resolution was achieved by monitoring plasmolysis in epidermal cells in tissue sections, incubated in selected osmotica using a light microscope method. Decreasing the osmotic potential [ΨΠ (more negative)] of the incubation medium increased the proportion (percent) of plasmolyzed epidermal cells. The pattern of increasing plasmolysis was sigmoidal with increasing osmolyte concentration. The value of ΨΠ for 50% of cells plasmolyzed, depended to some extent on the osmolyte used. The value of ΨΠ became slightly less negative for the osmolytes tested in the order: 1) mannitol, 2) sucrose, and 3) artificial cherry juice (a solution comprising the five major osmolytes of sweet cherry juice in the appropriate proportions and concentrations). There was little difference in the value of ΨΠ at 50% plasmolysis between the cultivars Hedelfinger, Sam, and Sweetheart. In all three cultivars, the value of ΨΠF (measured for expressed juice using an osmometer) was markedly more negative than that of ΨΠS (measured for 50% plasmolysis). Incubating skin segments in juice from the same fruit resulted in the plasmolysis of most (85.7% to 96.4%) of the epidermal cells. As fruit development progressed from stage II [27 day after full bloom (DAFB)] to the fully mature stage III (97 DAFB), plasmolysis occurred for increasingly more negative values of ΨΠ. Moreover, the difference between the osmotic potential values recorded for the flesh ΨΠF and for the skin ΨΠS increased. Plasmolysis of epidermal cells was accompanied by a marked swelling of their walls. The results indicate a marked difference in the osmotic potential of flesh (ΨΠF trended more negative) and skin cells (ΨΠS trended less negative).


1978 ◽  
Vol 79 (2) ◽  
pp. 356-370 ◽  
Author(s):  
C L Marcelo ◽  
Y G Kim ◽  
J L Kaine ◽  
J J Voorhees

A population of neonatal mouse keratinocytes (epidermal basal cells) was obtained by gentle, short-term trypsin separation of the epidermal and dermal skin compartments and discontinuous Ficoll gradient purification of the resulting epidermal cells. Over 4--6 wk of culture growth at 32--33 degrees C, the primary cultures formed a complete monolayer that exhibited entire culture stratification and upper cell layer shedding. Transmission and scanning electron microscopy demonstrated that the keratinocyte cultures progressed from one to two cell layers through a series of stratification and specialization phenomena to a six to eight cell layer culture containing structures characteristic of epidermal cells and resembling in vivo epidermal development. The temporal development of primary epidermal cell culture specialization was confirmed by use of two histological techniques which differentially stain the specializing upper cell layers of neonatal mouse skin. No detectable dermal fibroblast co-cultivation was demonstrated by use of the leucine aminopeptidase histochemical technique and routine electron microscope surveillance of the cultures. Incorporation of [3H]thymidine ([3H]Tdr) was greater than 85% into DNA and was inhibited by both 20 micron cytosine arabinoside (Ara-C) and low temperature. Autoradiography and 90% inhibition of [3H]Tdr incorporation by 2 mM hydroxyurea indicated that keratinocyte culture DNA synthesis was scheduled (not a repair phenomenon). The primary keratinocytes showed an oscillating pattern of [3H]Tdr incorporation into DNA over the initial 23--25 days of growth. Autoradiography demonstrated that the cultures contained 10--30% proliferative stem cells from days 2-25 of culture. The reproducibility of both the proliferation and specialization patterns of the described primary epidermal cell culture system indicates that these cultures are a useful tool for investigations of functioning epidermal cell homeostatic control mechanisms.


1986 ◽  
Vol 34 (3) ◽  
pp. 307-315 ◽  
Author(s):  
I Virtanen ◽  
A L Kariniemi ◽  
H Holthöfer ◽  
V P Lehto

The distribution of saccharide moieties in human interfollicular epidermis was studied with fluorochrome-coupled lectins. In frozen sections Concanavalin A (Con A), Lens culinaris agglutinin (LCA), Ricinus communis agglutinin I (RCAI), and wheat germ agglutinin (WGA) stained intensively both dermis and viable epidermal cell layers, whereas peanut agglutinin (PNA) bound only to living epidermal cell layers. Ulex europaeus agglutinin I (UEAI) bound to dermal endothelial cells and upper cell layers of the epidermis but left the basal cell layer unstained. Dolichos biflorus agglutinin (DBA) bound only to basal epidermal cells, whereas both soybean agglutinin (SBA) and Helix pomatia agglutinin (HPA) showed strong binding to the spinous and granular cell layers. On routinely processed paraffin sections, a distinctly different staining pattern was seen with many lectins, and to reveal the binding of some lectins a pretreatment with protease was required. All keratin-positive cells in human epidermal cell suspensions, obtained with the suction blister method, bound PNA, whereas only a fraction of the keratinocytes bound either DBA or UEAI. Such a difference in lectin binding pattern was also seen in epidermal cell cultures both immediately after attachment and in organized cell colonies. This suggests that in addition to basal cells, more differentiated epidermal cells from the spinous cell layer are also able to adhere and spread in culture conditions. Gel electrophoretic analysis of the lectin-binding glycoproteins in detergent extracts of metabolically labeled primary keratinocyte cultures revealed that the lectins recognized both distinct and shared glycoproteins. A much different lectin binding pattern was seen in embryonic human skin: fetal epidermis did not show any binding of DBA, whereas UEAI showed diffuse binding to all cell layers but gave a bright staining of dermal endothelial cells. This was in contrast to staining results obtained with a monoclonal cytokeratin antibody, which showed the presence of a distinct basal cell layer in fetal epidermis also. The results indicate that expression of saccharide moieties in human epidermal keratinocytes is related to the stage of cellular differentiation, different cell layers expressing different terminal saccharide moieties. The results also suggest that the emergence of a mature cell surface glycoconjugate pattern in human epidermis is preceded by the acquisition of cell layer-specific, differential keratin expression.


Foods ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 612
Author(s):  
Vânia Silva ◽  
Sandra Pereira ◽  
Alice Vilela ◽  
Eunice Bacelar ◽  
Francisco Guedes ◽  
...  

Sweet cherry (Prunus avium L.) is a fruit appreciated by consumers for its well-known physical and sensory characteristics and its health benefits. Being an extremely perishable fruit, it is important to know the unique attributes of the cultivars to develop cultivation or postharvest strategies that can enhance their quality. This study aimed to understand the influence of physicochemical characteristics of two sweet cherry cultivars, Burlat and Van, on the food quality perception. Several parameters (weight, dimensions, soluble solids content (SSC), pH, titratable acidity (TA), colour, and texture) were measured and correlated with sensory data. Results showed that cv. Van presented heavier and firmer fruits with high sugar content. In turn, cv. Burlat showed higher pH, lower TA, and presented redder and brightest fruits. The principal component analysis revealed an evident separation between cultivars. Van cherries stood out for their sensory parameters and were classified as more acidic, bitter, and astringent, and presented a firmer texture. Contrarily, Burlat cherries were distinguished as being more flavourful, succulent, sweeter, and more uniform in terms of visual and colour parameters. The results of the sensory analysis suggested that perceived quality does not always depend on and/or recognize the quality parameters inherent to the physicochemical characteristics of each cultivar.


2021 ◽  
Vol 175 ◽  
pp. 111494
Author(s):  
Excequel Ponce ◽  
Blanca Alzola ◽  
Natalia Cáceres ◽  
Madeline Gas ◽  
Catalina Ferreira ◽  
...  

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
José Quero-García ◽  
Philippe Letourmy ◽  
José Antonio Campoy ◽  
Camille Branchereau ◽  
Svetoslav Malchev ◽  
...  

AbstractRain-induced fruit cracking is a major problem in sweet cherry cultivation. Basic research has been conducted to disentangle the physiological and mechanistic bases of this complex phenomenon, whereas genetic studies have lagged behind. The objective of this work was to disentangle the genetic determinism of rain-induced fruit cracking. We hypothesized that a large genetic variation would be revealed, by visual field observations conducted on mapping populations derived from well-contrasted cultivars for cracking tolerance. Three populations were evaluated over 7–8 years by estimating the proportion of cracked fruits for each genotype at maturity, at three different areas of the sweet cherry fruit: pistillar end, stem end, and fruit side. An original approach was adopted to integrate, within simple linear models, covariates potentially related to cracking, such as rainfall accumulation before harvest, fruit weight, and firmness. We found the first stable quantitative trait loci (QTLs) for cherry fruit cracking, explaining percentages of phenotypic variance above 20%, for each of these three types of cracking tolerance, in different linkage groups, confirming the high complexity of this trait. For these and other QTLs, further analyses suggested the existence of at least two-linked QTLs in each linkage group, some of which showed confidence intervals close to 5 cM. These promising results open the possibility of developing marker-assisted selection strategies to select cracking-tolerant sweet cherry cultivars. Further studies are needed to confirm the stability of the reported QTLs over different genetic backgrounds and environments and to narrow down the QTL confidence intervals, allowing the exploration of underlying candidate genes.


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