USE OF THERMAL ANALYSIS TO MEASURE FREEZING RESISTANCE OF GRAPE BUDS

1986 ◽  
Vol 66 (4) ◽  
pp. 947-952 ◽  
Author(s):  
H. A. QUAMME
Keyword(s):  
Thermal Analysis ◽  
Vitis Vinifera ◽  
Cold Hardiness ◽  
Thermal Contact ◽  
Vitis Vinifera L ◽  
Rapid Rate ◽  
Stem Tissue ◽  
Freezing Resistance ◽  
Rate Of Cooling ◽  
The Mean

The effects of bud excision, cooling rate, and preconditioning temperature on the mean low-temperature exotherm (LTE) of grape buds were studied to determine the appropriate methodology for measurement of hardiness of Vitis vinifera L. and Vitis vinifera hybrid buds using thermal analysis. Excision of Maréchal Foch buds to exclude any of the stem tissue raised the LTE temperature above that obtained with the bud attached to a piece of the stem. Cooling rates between 1.5 and 10 °C h−1 did not affect the LTE temperature of Marechal Foch and Okanagan Riesling buds, but at the most rapid rate of cooling, 40 °C h−1, a lack of thermal contact between the sensor and the tissue produced an error in measurement. The LTE temperature determined on the buds of eight cultivars was within 0.9 °C of the temperature which killed 50% of the buds. Preconditioning the buds at −5 °C for 7 d and then −10 °C for 3 d improved the ability of thermal analysis to discriminate the differences in freezing resistance among the cultivars Marechal Foch, Okanagan Riesling and Lakemont, in the autumn; but not in mid-winter. Methods for mounting stem sections on the thermocouples were developed and are described.Key words: Grape, cold hardiness, supercooling, exotherm, Vitis

scholarly journals Bud dormancy pattern, chilling requirement, and cold hardiness in Vitis vinifera L. cv. ‘Chardonnay’ and ‘Riesling’

2021 ◽  
Author(s):  
Alireza Rahemi ◽  
Helen Fisher ◽  
Adam Dale ◽  
Toktam Taghavi ◽  
John M. Kelly
Keyword(s):  
Vitis Vinifera ◽  
Low Temperatures ◽  
Lake Erie ◽  
Cold Hardiness ◽  
Open Water ◽  
Vitis Vinifera L ◽  
Cold Temperatures ◽  
Commercial Vineyard ◽  
Chilling Hours ◽  
Dormancy Pattern

In recent years, new vineyards have been established in southwestern Ontario. The open water of Lake Erie provides some winter protection for Vitis hybrids and winter-hardy Vitis vinifera L. cultivars in this area. However, winter damage is possible when vines are grown distant from the open water or when lakes are frozen. To better understand the risks to winter survival, the dormancy and chilling phenology were studied over three winters from 2013-2016. Ten dormant canes of two V. vinifera cultivars, ‘Chardonnay’ and ‘Riesling’, were collected weekly from September 1 until March 30 from the mature vines in a commercial vineyard located at St. Williams (Ontario). The canes defoliated in early October, and the endodormancy was completed by the end of December. The cumulative chilling hours (0-7.2 °C) from defoliation until the completion of endodormancy were averaged 606 hours for ‘Chardonnay’ and 665 hours for ‘Riesling’. ‘Chardonnay’ buds were slightly less hardy than ‘Riesling’ to cold temperatures, with a threshold of about -24 °C for ‘Chardonnay’ and -25 °C for ‘Riesling’. Most primary buds of both cultivars died after February 16, 2015, and more than half died after February 12, 2014, due to severe low temperatures of -33.1 and -26 °C, respectively.

Review of Thermal Joint Resistance Models for Non-Conforming Rough Surfaces in a Vacuum

2003 ◽  
Author(s):  
M. Bahrami ◽  
J. R. Culham ◽  
M. M. Yovanovich ◽  
G. E. Schneider
Keyword(s):  
Experimental Data ◽  
Thermal Analysis ◽  
Flux Tube ◽  
Thermal Contact ◽  
Theoretical Models ◽  
Size Number ◽  
Data Points ◽  
Contact Models ◽  
The Mean ◽  
Contact Parameters

The thermal contact resistance (TCR) problem is categorized into three different problems: geometrical, mechanical, and thermal. Each problem includes a macro and micro scale sub-problem; existing theories and models for each part are reviewed. Empirical correlations for microhardness, and the equivalent (sum) rough surface approximation are discussed. Suggested correlations for estimating the mean absolute surface slope are summarized and compared with experimental data. The classical conforming rough contact models, i.e elastic and plastic, as well as elastoplastic models are reviewed. A set of scale (dimensionless) relationships are derived for the contact parameters, i.e. the mean microcontact size, number of micro-contacts, density of microcontacts, and the external load as functions of dimensionless separation, for the above models. These scale relationships are plotted; it is graphically shown that the behavior of these models, in terms of the contact parameters, are similar. The most common assumptions of existing thermal analysis are summarized. As basic elements of thermal analysis, spreading resistance of a circular heat source on a half-space and flux tube are reviewed, also existing flux tube correlations are compared. More than 400 TCR data points collected by different re-searchers during last forty years are grouped into two limiting cases: conforming rough, and elasto-constriction. Existing TCR models are reviewed and compared with the experimental data at these two limits. It is shown that the existing theoretical models do not cover both of the above-mentioned limiting cases.

Seasonal and geographic origin effects on cold hardiness of white spruce buds, foliage, and stems

1994 ◽  
Vol 24 (5) ◽  
pp. 1066-1070 ◽  
Author(s):  
David G. Simpson
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Low Temperature ◽  
North American ◽  
Electrolyte Leakage ◽  
Cold Hardiness ◽  
Geographic Origin ◽  
White Spruce ◽  
Stem Tissue ◽  
Early Fall

Cold hardiness of dormant vegetative buds from white spruce (Piceaglauca (Moench) Voss) trees originating from throughout the species' North American range was measured by differential thermal analysis between August and April at Vernon, B.C. Buds were least hardy in early fall (low temperature exotherm −12 to −25 °C) and most hardy midwinter (low temperature exotherms −20 to −34 °C). Buds of northerly origin trees were more hardy in early fall (September–October) than buds of more southerly origin trees. Similar results were observed for foliage and stem tissue in early fall using electrolyte leakage measurements following −16 °C freezing.

scholarly journals Relationship Between Bud Cold Hardiness and Budbreak in Two Vitis vinifera L Cultivars, Chardonnay and Thompson Seedless

2021 ◽  
Author(s):  
Francisco J. Pérez ◽  
Sebastián Rubio
Keyword(s):  
Vitis Vinifera ◽  
Cold Hardiness ◽  
Statistical Significance ◽  
Rank Test ◽  
Vitis Vinifera L ◽  
Dormancy Breaking ◽  
Thompson Seedless ◽  
Cold Temperatures ◽  
Kaplan Meier ◽  
Winter Cold

AbstractThe lack of winter cold is a severe limitation for the cultivation of grapevines (Vitis vinifera L) in areas with warm winter climates. This phenomenon is currently becoming quite important due to global warming, which will increase winter temperatures in many temperate regions of the planet where grapevines are cultivated. Although various physical and chemical stimuli have been used to address the lack of winter cold in grapevine cultivation, quantitative studies on its effects on different cultivars are limited. Here, the effects of (a) low temperatures during endodormancy (ED), (b) temperature increases during eco-dormancy (ECD) and (c) the effects of dormancy-breaking compounds such as hydrogen cyanamide (HC) and sodium azide (AZ) on the budburst of an early budbreak cultivar, Chardonnay, and an late budbreak cultivar, Thompson seedless, were assessed. The results were analysed by the Kaplan–Meier method, and the log-rank test was used to establish statistical significance between the control and treatments. In general, Chardonnay grapevines were more sensitive than Thompson seedless grapevines to all budbreak stimuli, and a temperature increase during ECD was the stimulus that had the greatest effect on the budbreak in both cultivars. Exposure to cold temperatures during ED increased the cold hardiness and improved the budbreak in both cultivars. Based on the results, a relationship between the degree of bud cold hardiness and budbreak potential is suggested, and it is proposed that the greater the cold hardiness achieved by the buds, the better their subsequent budbreak will be.

Resveratrol oligomers from Vitis Vinifera L. stems

Planta Medica ◽  
2007 ◽  
Vol 73 (09) ◽  
Author(s):  
H Amira-Guebailia ◽  
T Richard ◽  
S Rouaiguia ◽  
P Waffo Tueguo ◽  
JC Delaunay ◽  
...  
Keyword(s):  
Vitis Vinifera ◽  
Vitis Vinifera L

Biotransformation of 4-hydroxybenzoic acid in the rhizosphere of grapevine (Vitis vinifera L.)

2017 ◽  
Vol 40 (1) ◽  
pp. 95-102 ◽  
Author(s):  
B. Wang ◽  
T. Zhou1 ◽  
K. Li ◽  
X.W. Guo ◽  
Y.S. Guo ◽  
...  
Keyword(s):  
Vitis Vinifera ◽  
Vitis Vinifera L ◽  
Hydroxybenzoic Acid
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