below hole in C. pectinata ; 2 months after injection. ( I ) Injury at 2 cm below hole in C. endentata ; 12 months after injection. ( J ) Transverse section of wound periderm in C. pectinata cut 2 months after injection; showing tissue from surface
Jack B. Fisher, Anders Lindström, and Thomas E. Marler
D.S. Achor, H. Browning, and L.G. Albrigo
Young expanding leaves of `Ambersweet' [Citrus reticulata Blanco × C. paradisi Macf. × C. reticulata) × C. sinensis (L) Osb.] with feeding injury by third larval stage of citrus leafminer (Phyllocnistis citrella) were examined by light and electron microscopy for extent of injury and tissue recovery over time. Results confirmed that injury is confined to the epidermal layer, leaving a thin covering over the mine tunnel that consisted of the cuticle and outer cell wall. Wound recovery consisted of two possible responses: the production of callus tissue or the formation of wound periderm. The production of callus tissue developed within 3 days of injury when the uninjured palisade or spongy parenchyma below the injured epidermis produced callus tissue through periclinal or diagonal cell divisions. After 1 month, the entire epidermis was replaced by callus tissue. In the absence of secondary microbial invasion, this callus tissue developed a thick cuticle, followed by development of a covering of platelet wax after 4 months. Alternatively, wound periderm formed if the outer cuticular covering was torn before the cuticle had developed sufficiently to prevent the exposed cells from being desiccated or invaded by fungi, bacteria, or other insects. The wound periderm consisted of a lignified layer of collapsed callus cells, a suberized phellem layer, and a multilayered phelloderm-phellogen. Since there were always cellular collapse or fungi and bacteria associated with wound periderm formation, it was determined to be a secondary effect, not a direct effect of leafminer feeding.
William M. Walter Jr., Betsy Randall-Schadel, and William E. Schadel
Wound healing in cucumber fruit (Cucumis sativus L., cv. Calypso) was studied using histological and degradative techniques. A thick exudate appeared at the wounded surface shortly after wounding. This material retarded water loss and possibly aided in the formation of sclerified parenchyma observed 24 hours after wounding. The sclerified material was positive to a modified Weisner stain, indicating lignification was occurring. Wound periderm (cork) was initiated directly beneath the sclerified parenchyma cells within 48 hours after wounding. The cork layers were positive to Sudan IV stain, indicating suberin was being formed. The rate of phellem development decreased by 6 days after wounding. By day 7, younger phellem cells and sclerified parenchyma cells were stained by Sudan IV. Degradation of the wound tissue by chemical procedures demonstrated that relatively large amounts of lignin and suberin were deposited during healing. Fragments from the lignin degradation Indicated that lignin was composed mainly of gualacyl and p-hydroxyphenyl residues. Suberin was found to contain mainly 1,16-hexadecane and 1,18-osctadecene decarboxylic acids detected as the silylated diol derivatives.
D.S. Achor, L.G. Albrigo, and C.W. McCoy
Upper surface leaf lesions on `Sunburst' mandarin [(Citrus reticulata Blanco × (C. paradisi Macf. × C. reticulate)] associated with feeding by the citrus rust mite [Phyllocoptruta oleivora (Ashm.)] are more severe than those on other citrus cultivars. Development of leaf lesions on `Sunburst' mandarin and two other cultivars were examined by light and electron microscopy. Damaged leaves treated with a fungicide confirmed that the anatomical changes on `Sunburst' are an enhanced wound periderm response to feeding injury by rust mite and not the result of fungal invasion.
Peter D. Petracek and Craig Davis
Postharvest pitting of citrus fruit is a recently defined peel disorder that is caused by high-temperature storage (>10°C) of waxed fruit. We examined the anatomy of pitted white grapefruit peel to improve our understanding of this disorder and assist in its diagnosis. Scanning, light, and transmission micrographs showed that postharvest pitting is characterized by the collapse of oil glands. Cells enveloping the oil glands are the cells of primary damage. Oil gland rupture may occur anywhere around the oil gland, but often occurs in regions farthest from the epidermal cells. Adjacent parenchyma cells are damaged as the oil spreads. Epidermal and hypodermal cells are often damaged during severe oil gland collapse. In contrast, chilling injury is characterized by the collapse of epidermal and hypodermal cells. Oil glands are affected only in severe cases of chilling injury. Oleocellosis (oil spotting) is often characterized by the collapse of epidermal and hypodermal cells, but cells enveloping the oil gland are typically not damaged. Physical damage is characterized by damage of epidermal cells, a wound periderm, and presence of secondary pathogens.
Jollanda Effendy, Don R. La Bonte, and Niranjan Baisakh
developed and developing countries. Skinning is inevitable and the rapid deposition of wound periderm at the injury site is critical. Wound periderm, which is similar to native periderm, forms best at 28 to 30 °C and relative humidity above 85% ( Kushman and
Xiang Wang, Ramón A. Arancibia, Jeffrey L. Main, Mark W. Shankle, and Don R. LaBonte
.H. 2007 Antioxidant activity and phenolic composition in ‘Beauregard’ sweetpotato are affected by root size and leaf age J. Amer. Soc. Hort. Sci. 132 447 451 Sabba, R.P. Lulai, E.C. 2002 Histological analysis of the maturation of native and wound periderm
Ramón A. Arancibia, Jeffrey L. Main, and Christopher A. Clark
isolated from end or tip rots are also endophytic and may be present inside the roots before curing ( da Silva and Clark, 2012 ; Stokes et al., 2012 ). Since curing promotes rapid wound periderm formation, resulting in reduced water loss, the effect of
Mildred N. Makani, Steven A. Sargent, Lincoln Zotarelli, Donald J. Huber, and Charles A. Sims
. Zotarelli, L. Rowland, D.L. Dukes, M.D. Sargent, S.A. 2014 Drip as alternative irrigation method for potato in Florida sandy soils Amer. J. Potato Res. 91 504 516 Sabba, R.P. Lulai, E.C. 2002 Histological analysis of the maturation of native and wound
Thanidchaya Puthmee, Kenji Takahashi, Midori Sugawara, Rieko Kawamata, Yoshie Motomura, Takashi Nishizawa, Toshiyuki Aikawa, and Wilawan Kumpoun
. 15 546 553 Schreiber, L. Franke, R. Hartmann, K. 2005 Wax and suberin development of native and wound periderm of potato ( Solanum tuberosum L.) and its relation to peridermal transpiration Planta 220 520 530 Seko, T. 2004 Melon Gendai-nougyo. 2004 2