The mechanical properties and anatomy of fruit wall peels and their enzyme-isolated cuticular membranes (CM) are reported for three cherry tomato (Lycopersicon esculentum Mill.) cultivars that are crack-resistant, crack-intermediate, and crack-prone (i.e., Inbred 10, Sweet 100, and Sausalito Cocktail, respectively). The resistant and intermediate fruit peels strain-hardened when extended progressively; those of the crack-prone cultivar did so only modestly. The CM of all cultivars strain-hardened when extended with small forces; the CM of the intermediate and crack-prone cultivars strain-softened under tensile forces that did not strain-soften the crack-resistant cultivar. The peels and CM of the resistant cultivar were stiffer, stronger, and required more energy to break than crack-prone peels. The CM of crack-resistant peels developed deeper within the subepidermis than in the crack-prone or crack-intermediate peels. The CM in the outer epidermal periclinal walls of the crack-resistant and crack-intermediate cultivars was thicker than that of crack-prone peels. These data indicate that CM thickness can be used to gauge crack susceptibility among cherry tomato fruit, which can be useful in breeding programs and would facilitate QTL mapping of the underlying genetic factors.
Antonio J. Matas, Eward D. Cobb, Dominick J. Paolillo Jr. and Karl J. Niklas
Steven J.R. Underhill, Richard L. McLauchlan and Irving L. Eaks
In accordance with the currently approved Australian citrus disinfestation protocol for export to Japan, degreened `Eureka' lemons [Citrus limon (L.) Burm.] were cold-stored for 2 weeks at 1C. Following cold treatment, fruit were stored at 5C for 3 weeks, then transferred to 20C for an additional week to simulate transportation and handling. Fruit harvested early in the season were more susceptible to chilling injury than fruit harvested later, with 62% having lesions >1 cm2 after 2 weeks at 1C. Most of the chilling injury occurred after subsequent storage (at 5C) rather than immediately after the 1C treatment. Injury was different from surface pitting or oleocellosis, manifesting as large uniform surface lesions 2 to 3 cm in diameter that rapidly discolored following storage at 20C. Although the oil glands were flattened, the collenchyma layer immediately above the oil gland remained intact. Cellular discoloration was localized around the oil gland, possibly indicating a lateral release of oil gland contents. Nondegreened late-season fruit developed substantially lower levels of chilling injury.
Kendra M. Blaker and James W. Olmstead
of cutin and associated waxes ( Esau, 1977 ). Collenchyma cells and phloem elements have thickened primary cell walls that provide tensile strength to surrounding tissues. Xylem and sclerenchyma cells such as fibers and sclereids have thick and
Huan-Keng Lin, Tzu-Yao Wei, Chin-Mu Chen and Der-Ming Yeh
. and Clematis maritima L., primary phloem fiber and collenchyma are displaced outward by plant development, which led to disrupting the mechanical integrity, but not in semiself-supporting Clematis recta L. ( Rowe et al., 2004 ). Modulus of
Baomei Yang, Guoliang Li, Shaohai Yang, Zhaohuan He, Changmin Zhou and Lixian Yao
epidermal tissue development, thicken the cell wall, and improve the mechanical resistance of collenchymas against bacterial parasite. In addition, K can adjust cell membrane permeability, increase turgor pressure, improve membrane stability and tissue
Andreas Winkler, Stefanie Peschel, Kathleen Kohrs and Moritz Knoche
cells which have a more negative ψ S ( Grimm and Knoche, 2015 ; Simon, 1977 ). Unlike the collenchyma-type epidermal and hypodermal cells, flesh cells are parenchyma cells that are structurally weak and begin to crack. Third, the bursting of individual
Bhaskar R. Bondada
mesophyll tissues interrupted by several fasciated small veins. Scale bars: 50 μm ( A–D ). BSE = bundle sheath extension; C = collenchyma cells; RT = replacement tissue; blue arrowheads = vascular bundles; white arrow heads = subepidermal islet of mesophyll
through the sun-exposed chromated surfaces in healthy and afflicted clusters revealed a colorless single layer of epidermis followed by a ridge of collenchyma cells, cortex, vascular bundles, and central pith ( Figs. 3D and 4B ). In the pigmented portion