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Xylem discontinuity in Vitis vinifera L. berries

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dc.contributor.advisor Lombard, Porter B.
dc.creator Creasy, Glen L.
dc.date.accessioned 2011-11-22T22:11:40Z
dc.date.available 2011-11-22T22:11:40Z
dc.date.copyright 1991-08-05
dc.date.issued 1991-08-05
dc.identifier.uri http://hdl.handle.net/1957/25736
dc.description Graduation date: 1992 en_US
dc.description.abstract Several effects of xylem discontinuity in Pinot noir and Merlot grape berries were studied. There was a reduction in the amount of apoplastic dye (Eosin Y or azosulfamide) uptake through cut pedicels into soft versus firm berries, suggesting a reduction in maximal xylem flow at that time. Both greenhouse and field grown Pinot noir berries took up less dye after softening. Merlot berries, collected on one date from the field and separated by hand into four developmental categories, took up different amounts of azosulfamide dye according to category. Soft green and just colored berries took up 30%, and fully colored berries 70%, less dye than firm green berries. The reduction in xylem conductivity was related to the developmental stage of each individual berry and not the cluster as a whole. The accumulation of K⁺ (primarily a phloem transported element) and Ca²⁺ (primarily a xylem transported element) differed in field grown Pinot noir berries during maturation. On a per berry basis K⁺ increased after veraison, suggesting greater phloem activity, but Ca content remained stable after veraison, suggesting little xylem activity. Berry diameters on pre-veraison clusters on well watered vines increased slightly; those on unwatered vines decreased, losing 0.87 mm in diameter during day 3 of the experiment. Pre-veraison berry deformabilities were 380% higher in unwatered versus watered vines on day 4. Bagging pre-veraison clusters to slow transpiration reduced the rate of berry diameter loss and softness only slightly. Pre-veraison berry shrivelling occurred before vine wilting. Post-veraison Pinot noir berry diameters and deformabilities in the greenhouse were not significantly affected by short term vine water stress. Heat girdling cluster peduncles to block phloem flow reduced pre-veraison berry growth rates to near zero and increased the rate of diameter loss significantly in post-veraison berries. Girdling had little effect on pre-veraison berry deformabilities, but a large effect on those of post-veraison berries. The different berry responses to vine water stress and peduncle girdling before and after veraison suggested a change in xylem activity. Prior to veraison there was rapid water loss from the berry to a stressed vine, but after veraison berries were more isolated, showing little response to vine water stress. Blocking phloem transport in the cluster peduncle prior to veraison reduced berry growth to almost zero but affected deformability little, which suggested that xylem was maintaining berry size and firmness. Under the same conditions post-veraison berries lost both size and firmness rapidly, which suggested little xylem activity. en_US
dc.language.iso en_US en_US
dc.subject.lcsh Xylem en_US
dc.subject.lcsh Plants, Motion of fluids in en_US
dc.subject.lcsh Grapes -- Physiology en_US
dc.title Xylem discontinuity in Vitis vinifera L. berries en_US
dc.type Thesis/Dissertation en_US
dc.degree.name Master of Science (M.S.) in Horticulture en_US
dc.degree.level Master's en_US
dc.degree.discipline Agricultural Sciences en_US
dc.degree.grantor Oregon State University en_US
dc.contributor.committeemember McDaniel, Mina
dc.contributor.committeemember Breen, Patrick J.
dc.contributor.committeemember Gabe, Don
dc.description.digitization File scanned at 300 ppi (Monochrome, 24-bit Color) using Scamax Scan+ V.1.0.32.10766 on a Scanmax 412CD by InoTec in PDF format. LuraDocument PDF Compressor V.5.8.71.50 used for pdf compression and textual OCR. en_US
dc.description.peerreview no en_us


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