scholarly journals Assessment of Freeze Injury of Grapevine Green Tissues in Response to Cultivars and a Cryoprotectant Product

HortScience ◽  
2016 ◽  
Vol 51 (7) ◽  
pp. 856-860 ◽  
Author(s):  
Michela Centinari ◽  
Maria S. Smith ◽  
Jason P. Londo
Keyword(s):  
Freezing Stress ◽  
Practical Significance ◽  
Cabernet Sauvignon ◽  
Freeze Injury ◽  
Spring Frost ◽  
Cultivar Selection ◽  
Temperature Exposure ◽  
Controlled Freezing ◽  
Whole Plants ◽  
Shoot Mortality

Spring frosts and subsequent crop losses threaten the economic sustainability of fruit crop producers all over the world. This study used a controlled-freezing technique to impose a post-budburst freezing stress to grapevine shoots forced from one-node cuttings [‘Albariño’, ‘Cabernet Franc’, ‘Cabernet Sauvignon’, and ‘Pinot Grigio’ (Vitis vinifera)] and whole plants [‘Noiret’ (Vitis hybrid)]. Our goal was to investigate the incidence of freeze injury among cultivars, stage of phenological development, and a potassium salt-based fertilizer (KDL) with potential cryoprotectant activity. Among the V. vinifera cultivars, the incidence of mortality of shoots exposed to −3.5 °C was highest for ‘Albariño’ (71%) and lowest for ‘Cabernet Sauvignon’ (51%). Cuttings sprayed with KDL 24 hours before cold temperature exposure exhibited 16% lower shoot mortality and lower osmotic potential (Ψs) (−0.92 MPa) than the unsprayed cuttings (−0.77 MPa). However, application of KDL did not impact shoot mortality for whole ‘Noiret’ vines. Mortality for ‘Noiret’ shoots greatly increased with the advancement of phenological development, ranging from 10% in wooly buds to 78% in shoots ≈10-cm long. The practical significance of KDL remains questionable; cultivar selection still appears to be a more reliable method for avoiding spring frost, by planting late bursting cultivars in more frost-prone areas.

scholarly journals Freezing stress survival mechanisms in Vaccinium macrocarpon Ait. terminal buds

2020 ◽  
Vol 40 (7) ◽  
pp. 841-855
Author(s):  
Camilo Villouta ◽  
Beth Ann Workmaster ◽  
Jenny Bolivar-Medina ◽  
Smith Sinclair ◽  
Amaya Atucha
Keyword(s):  
Cold Hardiness ◽  
Liquid Water Content ◽  
Vaccinium Macrocarpon ◽  
Freezing Stress ◽  
Cold Temperatures ◽  
Woody Perennial ◽  
Stress Survival ◽  
Mri Scans ◽  
Terminal Buds ◽  
Controlled Freezing

Abstract Plants’ mechanisms for surviving freezing stresses are essential adaptations that allow their existence in environments with extreme winter temperatures. Although it is known that Vaccinium macrocarpon Ait. buds can acclimate in fall and survive very cold temperatures during the winter, the mechanism for survival of these buds is not known. The main objective of this study was to determine which of the two major mechanisms of freezing stress survival, namely, deep supercooling or freeze-induced dehydration, are employed by V. macrocarpon terminal buds. In the present study, no low-temperature exotherms (LTEs) were detected by differential thermal analysis. Furthermore, a gradual reduction of relative liquid water content in the inner portions of buds during magnetic resonance imaging (MRI) scans performed between 0 and −20 °C (where no damage was detected in controlled freezing tests (CFT)) indicates these buds may not deep supercool. The higher ice nucleation activity of outer bud scales and the appearance of large voids in this structure in early winter, in conjunction with the MRI observations, are evidence supportive of a freeze-induced dehydration process. In addition, the presence of tissue browning in acclimated buds as a result of freezing stress was only observed in CFT at temperatures below −20 °C, and this damage gradually increased as test temperatures decreased and at different rates depending on the bud structure. Ours is the first study to collect multiple lines of evidence to suggest that V. macrocarpon terminal buds survive long periods of freezing stress by freeze-induced dehydration. Our results provide a framework for future studies of cold hardiness dynamics for V. macrocarpon and other woody perennial species and for the screening of breeding populations for freezing stress tolerance traits.

scholarly journals INFLUENCE OF SIMULATED SPRING FROST ON GROWTH AND YIELD OF THREE BARLEY CULTIVARS

1982 ◽  
Vol 62 (1) ◽  
pp. 81-88 ◽  
Author(s):  
J. S. McKENZIE ◽  
D. G. FARIS ◽  
R. M. DE PAUW
Keyword(s):  
Hordeum Vulgare ◽  
Frost Resistance ◽  
Spring Barley ◽  
Growth And Yield ◽  
Freezing Stress ◽  
Yield Reduction ◽  
Hordeum Vulgare L ◽  
Spring Frost ◽  
Barley Cultivars ◽  
Freezing Chamber

Three spring barley (Hordeum vulgare L.) cultivars were planted at four seeding dates to evaluate the effect of a simulated frost at the two-leaf stage on growth and yield. A portable field freezing chamber was used to subject the plants to a − 5.6 °C stress. The frost caused 49, 64 and 68% injury to the leaves and delayed heading by 2.4, 1.4 and 2.4 days in Gait, Atlas and Olli, respectively. Frost also reduced the number of tillers per plant, ripe heads per plant and plants per plot in all cultivars. Although the late-maturing cultivar Galt had the most leaf frost resistance, the average 13.8% yield reduction within all three cultivars, owing to the freezing stress, was not significantly different between any of the cultivars. Complete defoliation by clipping resulted in no further reduction in yield than that which occurred from partial defoliation by freezing. Delayed seeding resulted in an 8.6% reduction in yield. Frost reduced the yield of early seeded cultivars by 9.8% and late-seeded cultivars by 17.1%.

Nutritional evaluation of five species of forage brassica

2012 ◽  
pp. 31-37 ◽  
Author(s):  
C.T. Westwood
Keyword(s):  
Dry Matter ◽  
Nutritional Value ◽  
Nutritive Value ◽  
Brassica Species ◽  
Ruminant Nutrition ◽  
Nutritional Evaluation ◽  
Cultivar Selection ◽  
Metabolisable Energy ◽  
Whole Plants ◽  
Forage Rape

Despite a growing interest in ruminant nutrition and the ongoing, widespread use of forage brassicas, there is an absence of data that adequately describe the nutritional value of modern brassica cultivars in New Zealand. Five forage brassica species represented by 30 cultivars were evaluated in single-site, single-year trials in the South Island. Replicated plots of leafy turnips, bulb turnips, rape, swede and kale were harvested at 53, 91, 98, 181 and 186 days after sowing, respectively. Whole plants were dissected to leaf, stem and bulb and/or petiole and components assessed for nutritive value. Quality differed significantly among and within brassica species. Within species, percent dry matter (DM) was consistent for rape, bulb turnip and leaf turnip, but differed significantly among cultivars in kale and swede. Mean metabolisable energy (MJ ME) content at harvest was highest for swede (13.8 MJ ME/ kg DM) and lowest for kale (11.2 MJ ME/kg DM). For all brassica species, fibre content as estimated by neutral detergent fibre (NDF) content was below optimum for ruminal function, highlighting the importance of high NDF supplementary feeds for brassica-fed stock. For some but not all brassica species, nutritive value may be modified by cultivar selection however factors not investigated in this study including sowing rate and time from sowing to harvest remain important potential moderators of forage brassica quality. Keywords: Forage brassica, leafy turnip, bulb turnip, forage rape, swede, kale, nutritive value, feed testing

Wheat frost injury — freezing stress and photosynthesis

1977 ◽  
Vol 28 (4) ◽  
pp. 557 ◽  
Author(s):  
H Marcellos
Keyword(s):  
Temperature Interval ◽  
Net Photosynthesis ◽  
Photosynthesis Rate ◽  
Freezing Stress ◽  
Stress Recovery ◽  
Mild Stress ◽  
Field Crops ◽  
Frost Injury ◽  
Underlying Mechanisms ◽  
Whole Plants

Although the lethal consequences of radiation frosts on wheat plants have been well described, effects of sublethal freezing have received little study. In this paper, studies of injury to leaves caused by freezing, and its influence on photosynthesis after thawing, are reported. Glasshouse-grown plants of three spring wheats were frozen at several temperatures in the range 0 to –4.5°C and their reaction to freezing stress measured. Injury to leaves caused by freezing stress was found to range from no damage to death over a temperature interval of 2°. Upper leaves were more resistant than lower, and the cultivar Z501 was found to be hardier by about l� than either Timgalen or Gamut. Net photosynthesis by whole plants in the period after thawing was reduced to levels as low as 30° of normal rates following mild stress, recovery to normal rates occurring by the following day. Severely stressed plants failed to recover over a 3 day period. Stomatal resistances were unaffected by low to mild freezing stress and could not explain the large reductions in photosynthesis rate following these stresses. The results have been discussed in relation to the underlying mechanisms, and to their implications for field crops.

scholarly journals Measurement of Chlorophyll Fluorescence as a Heat Stress Indicator in Tomato: Laboratory and Greenhouse Comparisons

2001 ◽  
Vol 126 (2) ◽  
pp. 188-194 ◽  
Author(s):  
D.H. Willits ◽  
M.M. Peet
Keyword(s):  
Heat Stress ◽  
Chlorophyll Fluorescence ◽  
Lycopersicon Esculentum ◽  
Laboratory Tests ◽  
Leaf Temperature ◽  
Laboratory Procedure ◽  
Stress Indicator ◽  
Temperature Controlled ◽  
Temperature Exposure ◽  
Whole Plants

Chlorophyll fluorescence was measured under both laboratory and greenhouse conditions in an effort to develop a quick, reliable, and inexpensive laboratory procedure capable of predicting heat stress experienced by tomato (Lycopersicon esculentum Mill.) under greenhouse conditions. The laboratory tests consisted of measurements of the ratio of variable to maximal chlorophyll fluorescence (Fv/Fm) performed on leaf discs taken from whole tomato leaves and placed on a temperature controlled plate. Comparisons were made with greenhouse measurements of the same parameter conducted on intact leaves of whole plants exposed to different temperature treatments imposed by manipulation of the aerial environment of the greenhouse. Dark adaption periods ranging from 15 min to all day in the greenhouse and temperature exposure periods ranging from 5 min to 60 min in the laboratory were compared to find the best correlation between the two tests. Best agreement was obtained with 60 min treatment times in the laboratory and 60 min dark adaption periods in the greenhouse. Fv/Fm decreased quadratically with increasing leaf temperature in a similar fashion in both tests, suggesting that the laboratory approach can adequately predict plant response to greenhouse heat stress.

scholarly journals (436) Comparative Cold Hardiness and Freezing Behavior of Leaves, Buds, and Flowers in Selected Woody Plants in Northern Latitudes

HortScience ◽  
2005 ◽  
Vol 40 (4) ◽  
pp. 1077A-1077
Author(s):  
A.M. Shirazi ◽  
M.V. Thierry
Keyword(s):  
Woody Plants ◽  
Cold Hardiness ◽  
Extreme Temperature ◽  
Freezing Stress ◽  
Ion Leakage ◽  
Spring Frost ◽  
Cornus Mas ◽  
Northern Latitudes ◽  
Cold Hardy ◽  
Eventual Death

It is not well known how cold-hardy new buds and emerging leaves or flowers are during spring. Extreme temperature fluctuations that sometimes bring early frost in spring (April–May) are very common in northern latitudes and cause severe damage to emerging leaves and flowers. Even though most woody plants can tolerate frost in spring, others show early tissue damage and can fully recover. There are some trees, e.g., Japanese maples (Acer palmatum) that when leaves are damaged due to spring frost, the results include severe dieback and eventual death. We tested new flowers and leaves of four crabapples: Malus ×micromalus, M. sargentii, `Mary Potter', and M. hupehensis, after budbreak for 3 years using electrical conductivity (EC) and differential thermal analysis (DTA) in spring: May 1997, Apr. 1998, and Apr. 2000, at The Morton Arboretum. Both flowers and leaves can tolerate from –6 to –12 °C and we observed higher ion leakage in leaves than flowers. The high temperature exotherm (HTE) of flowers were –8 to –10 °C in April. In a companion study, testing other species that had premature budbreak due to “near lethal” (sublethal) freezing stress in Jan. 2001, the following HTE were observed: Cornelian cherry (Cornus mas) flower (about –7.5 °C), Spindle trees leaves (about –6 °C), Judd's viburnum (Viburnum ×juddii) (about –8 °C), Brevipetala witch-hazel (Hamamelis mollis`Brevipetala') flower (about –5 °C), redbud (Cercis candensis) flower (about –9 °C), flowering quince (Chaenomeles ×superba) flower (–8 °C). Multiple LTE at –13, –18, –22, and –27 °C were observed for Judd's viburnum. This information could be useful for selection and breeding of woody plants.

The structure of membranes and membrane proteins embedded in amorphous ice

1992 ◽  
Vol 50 (1) ◽  
pp. 432-433
Author(s):  
Uwe Lücken ◽  
Joachim Jäger
Keyword(s):  
Phase Transition ◽  
Transition Temperature ◽  
Membrane Proteins ◽  
Phase Transition Temperature ◽  
Lipid Vesicles ◽  
Freezing Stress ◽  
Amorphous Ice ◽  
Different Temperatures ◽  
Band Pass ◽  
Lipid Polymorphism

TEM imaging of frozen-hydrated lipid vesicles has been done by several groups Thermotrophic and lyotrophic polymorphism has been reported. By using image processing, computer simulation and tilt experiments, we tried to learn about the influence of freezing-stress and defocus artifacts on the lipid polymorphism and fine structure of the bilayer profile. We show integrated membrane proteins do modulate the bilayer structure and the morphology of the vesicles.Phase transitions of DMPC vesicles were visualized after freezing under equilibrium conditions at different temperatures in a controlled-environment vitrification system. Below the main phase transition temperature of 24°C (Fig. 1), vesicles show a facetted appearance due to the quasicrystalline areas. A gradual increase in temperature leads to melting processes with different morphology in the bilayer profile. Far above the phase transition temperature the bilayer profile is still present. In the band-pass-filtered images (Fig. 2) no significant change in the width of the bilayer profile is visible.

Specimen Preparation for Clinical Applications of X-Ray Microanalysis

1990 ◽  
Vol 48 (2) ◽  
pp. 328-329
Author(s):  
J.D. Shelburne ◽  
G.M. Roomans
Keyword(s):  
Carbon Coating ◽  
Clinical Applications ◽  
Point Of View ◽  
Practical Significance ◽  
Sweat Test ◽  
Specimen Preparation ◽  
Tissue Preparation ◽  
X Ray ◽  
Gallbladder Stones ◽  
Clinical Problems

Proper preparative procedures are a prerequisite for the validity of the results of x-ray microanalysis of biological tissue. Clinical applications of x-ray microanalysis are often concerned with diagnostic problems and the results may have profound practical significance for the patient. From this point of view it is especially important that specimen preparation for clinical applications is carried out correctly.Some clinical problems require very little tissue preparation. Hair, nails, and kidney and gallbladder stones may be examined and analyzed after carbon coating. High levels of zinc or copper in hair may be indicative of dermatological or systemic diseases. Nail clippings may be analyzed (as an alternative to the more conventional sweat test) to confirm a diagnosis of cystic fibrosis. X-ray microanalysis in combination with scanning electron microscopy has been shown to be the most reliable method for the identification of the components of kidney or gallbladder stones.A quantitatively very important clinical application of x-ray microanalysis is the identification and quantification of asbestos and other exogenous particles in lung.

Freeze-Fracture Studies of Membranes in Developing Sieve Elements in a Plant Tissue Culture

1980 ◽  
Vol 38 ◽  
pp. 636-637
Author(s):  
R. D. Sjolund ◽  
C. Y. Shih
Keyword(s):  
Plant Tissue ◽  
Cultured Cells ◽  
Freeze Fracture ◽  
Tissue Cultures ◽  
Sieve Elements ◽  
Intact Plants ◽  
Plant Tissue Cultures ◽  
Whole Plants ◽  
Energy Dependent ◽  
Similar Elements

The differentiation of phloem in plant tissue cultures offers a unique opportunity to study the development and structure of sieve elements in a manner that avoids the injury responses associated with the processing of similar elements in intact plants. Short segments of sieve elements formed in tissue cultures can be fixed intact while the longer strands occuring in whole plants must be cut into shorter lengths before processing. While iyuch controversy surrounds the question of phloem function in tissue cultures , sieve elements formed in these cultured cells are structurally similar to those of Intact plants. We are particullarly Interested In the structure of the plasma membrane and the peripheral ER in these cells because of their possible role in the energy-dependent active transport of sucrose into the sieve elements.

Collective Efficacy and Organizational Commitment in an Italian City Hall

2009 ◽  
Vol 14 (4) ◽  
pp. 363-371 ◽  
Author(s):  
Laura Borgogni ◽  
Silvia Dello Russo ◽  
Laura Petitta ◽  
Gary P. Latham
Keyword(s):  
Organizational Commitment ◽  
Collective Efficacy ◽  
Structural Equation ◽  
Structural Equation Models ◽  
Practical Significance ◽  
City Hall ◽  
Italian City ◽  
Public Sector Managers ◽  
The Individual ◽  
Level Group

Employees (N = 170) of a City Hall in Italy were administered a questionnaire measuring collective efficacy (CE), perceptions of context (PoC), and organizational commitment (OC). Two facets of collective efficacy were identified, namely group and organizational. Structural equation models revealed that perceptions of top management display a stronger relationship with organizational collective efficacy, whereas employees’ perceptions of their colleagues and their direct superior are related to collective efficacy at the group level. Group collective efficacy had a stronger relationship with affective organizational commitment than did organizational collective efficacy. The theoretical significance of this study is in showing that CE is two-dimensional rather than unidimensional. The practical significance of this finding is that the PoC model provides a framework that public sector managers can use to increase the efficacy of the organization as a whole as well as the individual groups that compose it.

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