scholarly journals Growth, Flowering, and Cold Hardiness of Rockrose in Western Oregon

2010 ◽  
Vol 20 (3) ◽  
pp. 652-659 ◽  
Author(s):  
Neil C. Bell ◽  
James Altland
Keyword(s):  
Low Temperatures ◽  
Cold Hardiness ◽  
Flowering Period ◽  
Drought Tolerant ◽  
Cistus Albidus ◽  
Cold Damage ◽  
Plant Form ◽  
Foliage Quality ◽  
Gold Star ◽  
Cistus Creticus

Ninety-three species, cultivars, and hybrid selections of rockrose (Cistus spp., Halimium spp., and ×Halimiocistus spp.) were evaluated for growth, flowering, and cold hardiness in a landscape trial in Aurora, OR, from 2004 to 2009. Plants were irrigated to aid establishment when planted in summer 2004, but thereafter were not watered, fertilized, or pruned throughout the trial. Cold damage was recorded following freezing events in Feb. 2006 and Dec. 2008 in which low temperatures were 20 and 17 °F, respectively. Those plants that consistently suffered the most cold damage were Halimium atriplicifolium, Cistus creticus ssp. creticus ‘Tania Compton’, Cistus ×pauranthus, and Cistus albidus forma albus. Other plants showed cold damage related to poor vigor. The length of the flowering period and foliage quality varied widely among plants in the evaluation. The plants with the longest flowering period were Halimium ×pauanum, Cistus inflatus, Cistus ×pulverulentus ‘Sunset’, and ×Halimiocistus ‘Ingwersenii’, all of which flowered for more than 55 days. Plant form and foliage quality declined drastically for some plants during the evaluation. Those that retained the best foliage quality included Cistus ×obtusifolius, Cistus ×laxus, Cistus salviifolius ‘Gold Star’, Cistus ‘Gordon Cooper’, Halimium lasianthum ‘Sandling’, Halimium ‘Susan’, and ×Halimiocistus sahucii. Based on ratings of foliage and bloom time, as well as hardiness, several Cistus are recommended as drought-tolerant groundcovers, including Cistus ×gardianus and C. ×obtusifolius. Cistus ×laxus, C. inflatus, Cistus ‘Gordon Cooper’, Cistus ‘Ruby Cluster’, and Cistus ‘Snow Fire’ are suggested as tall groundcovers or landscape specimens. Several Halimium are recommended for landscape use, including H. lasianthum ‘Sandling’, Halimium ‘Susan’, H. ×pauanum, and ×Halimiocistus ‘Ingwersenii’.

Flower cold hardiness: a potential determinant of the flowering sequence exhibited by bog ericads

1979 ◽  
Vol 57 (9) ◽  
pp. 997-999 ◽  
Author(s):  
R. J. Reader
Keyword(s):  
Low Temperatures ◽  
Cold Hardiness ◽  
Vaccinium Macrocarpon ◽  
Southern Ontario ◽  
Air Temperatures ◽  
Insect Pollinators ◽  
Cold Hardy ◽  
Vaccinium Myrtilloides ◽  
Potential Determinant ◽  
Ledum Groenlandicum

In laboratory freezing trials, cold hardiness of six types of bog ericad flowers differed significantly (i.e., Chamaedaphne calyculata > Andromeda glaucophylla > Kalmia polifolia > Vaccinium myrtilloides > Ledum groenlandicum > Vaccinium macrocarpon) at air temperatures between −4 and −10 °C but not at temperatures above −2 °C. At the Luther Marsh bog in southern Ontario, low temperatures (−3 to −7 °C) would select against May flowering by the least cold hardy ericads. Availability of pollinators, on the other hand, would encourage May flowering by the most cold hardy species. Presumably, competition for insect pollinators has promoted the diversification of bog ericad flowering peaks, while air temperature, in conjunction with flower cold hardiness, determined the order in which flowering peaks were reached.

Cold-Hardiness, Habitat and Winter Survival of Some Orchard Arthropods in Nova Scotia

1964 ◽  
Vol 96 (4) ◽  
pp. 617-625 ◽  
Author(s):  
A. W. MacPhee
Keyword(s):  
Nova Scotia ◽  
Air Temperature ◽  
Low Temperatures ◽  
Cold Hardiness ◽  
Winter Survival ◽  
Kings County ◽  
Winter Conditions ◽  
Cold Hardy

AbstractIn Kings County, Nova Scotia, low temperatures in the coldest nights of winter can differ by as much as 10°F. from one area to another. This has an important bearing on winter survival of some arthropods. Overwintering sites of orchard arthropods range from exposed situations which remain at air temperature to well protected ones on the ground where temperatures rarely go below 20°F. The cold-hardiness of each of 24 species of arthropods was measured: seven were sufficiently cold-hardy to survive any winter conditions in Nova Scotia, five were less cold-hardy but overwinter in well protected sites and twelve had marginal cold-hardiness, their mortality varying with the winter and the locality.

REDUCED COLD-HARDINESS OF PEAR PSYLLA (HOMOPTERA: PSYLLIDAE) CAUSED BY EXPOSURE TO EXTERNAL WATER AND SURFACTANTS

1996 ◽  
Vol 128 (5) ◽  
pp. 825-830 ◽  
Author(s):  
David R. Horton ◽  
Tamera M. Lewis ◽  
Lisa G. Neven
Keyword(s):  
Low Temperatures ◽  
Cold Hardiness ◽  
Dilute Solutions ◽  
Subzero Temperatures ◽  
Pear Psylla ◽  
External Water

AbstractOverwintering pear psylla, Cacopsylla pyricola (Foerster), were misted with water or with one of several dilute solutions of water and surfactant, and then exposed to a range of subzero temperatures for 24 h. Misted psylla had significantly greater mortality than unmisted controls. Increases in mortality occurred at temperatures as warm as −6°C, a temperature well within the range of conditions in the field. At extreme low temperatures (−18°C) there was virtually no mortality in the unmisted controls, whereas mortality approached or reached 100% in several of the misted groups. Temperatures necessary to kill 50% of insects estimated for topically treated psylla ranged between −2.6 and −12.7°C for surfactant-treated insects, and below −18°C for water-treated or control insects. The possibility of using surfactants and water for control of overwintering pear psylla is discussed.

scholarly journals Cold hardiness of peach flowers at different phenological stages

2018 ◽  
Vol 45 (No. 3) ◽  
pp. 119-124
Author(s):  
László Szalay ◽  
Imre Gergő Gyökös ◽  
Zsuzsanna Békefi
Keyword(s):  
Cold Hardiness ◽  
Freeze Tolerance ◽  
Phenological Stages ◽  
Climate Chamber ◽  
Cold Damage ◽  
Artificial Freezing ◽  
Delayed Development ◽  
Phenological Phases ◽  
Generative Organs

At the colder peach production regions it is important to know the cold hardiness of peach cultivars at different phenological stages of flowering. In our experiment, artificial freezing tests were conducted in a climate chamber in five selected years between the period of 2007 and 2016 to determine the freeze tolerance of generative organs of three peach cultivars (‘Venus’, ‘Redhaven’, ‘Piroska’) at different phenological stages of bloom. Based on the results of the laboratory freezing tests LT<sub>50</sub> values were calculated. Our results showed that LT<sub>50</sub> values of examined peach cultivars in swelled bud stage averaged over five years were between –6.8 and –11.2°C according to cultivar, and as phenological phases progressed, cold hardiness of generative organs decreased. At the end of bloom LT<sub>50</sub> values varied between –1.7 and –4.1°C. Cultivar ‘Piroska’ had the highest freeze tolerance and cultivar ‘Venus’ showed the lowest in each year studied. This study shows that trees with delayed development are more prone to cold damage to flowers.  

Parasites and low temperatures

Parasitology ◽  
1999 ◽  
Vol 119 (S1) ◽  
pp. S7-S17 ◽  
Author(s):  
D. A. Wharton
Keyword(s):  
Life Cycle ◽  
Cold Tolerance ◽  
Low Temperatures ◽  
Cold Hardiness ◽  
Free Living ◽  
Rate Of Growth ◽  
Subzero Temperatures ◽  
Growth Development ◽  
Epidemiological Significance

SUMMARYLow temperatures affect the rate of growth, development and metabolism of parasites and when temperatures fall below 0°C may expose the parasite to the potentially lethal risk of freezing. Some parasites have mechanisms, such as diapause, which synchronise their life cycle with favourable seasons and the availability of hosts. Parasites of endothermic hosts are protected from low temperatures by the thermoregulatory abilities of their host. Free-living and off-host stages, however, may be exposed to subzero temperatures and both freezing-tolerant and freeze-avoiding strategies of cold hardiness are found. Parasites of ectothermic hosts may be exposed to subzero temperatures within their hosts. They can rely on the cold tolerance adaptations of their host or they may develop their own mechanisms. Exposure to low temperatures may occur within the carcass of the host and this may be of epidemiological significance if the parasite can be transmitted via the consumption of the carcass.

OBSERVATIONS ON THE WHITE APPLE LEAFHOPPER, TYPHLOCYBA POMARIA (HEMIPTERA: CICADELLIDAE), AND ON THE MIRID PREDATOR BLEPHARIDOPTERUS ANGULATUS, AND MEASUREMENTS OF THEIR COLD-HARDINESS

1979 ◽  
Vol 111 (4) ◽  
pp. 487-490 ◽  
Author(s):  
A. W. MacPhee
Keyword(s):  
Nova Scotia ◽  
Low Temperatures ◽  
Cold Hardiness ◽  
Second Generation ◽  
Freezing Points ◽  
Two Generations ◽  
Predatory Mirid

AbstractTyphlocyba pomaria McA., with two generations per year, damages the leaves and defaces the fruit of apple. It was reduced in numbers in an experimental orchard by the predatory mirid Blepharidopterus angulatus (Fall.) which attacked the second generation. The cold-hardiness of T. pomaria and B. angulatus overwintering eggs, which had mean freezing points of −35 °C and −34 °C respectively, was sufficient to protect these species from winter low temperatures in Nova Scotia.

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.

scholarly journals Cold hardiness of peach flowers at different phenological stages

2018 ◽  
Vol 45 (No. 3) ◽  
pp. 119-124
Author(s):  
Szalay László ◽  
Gyökös Imre Gergő ◽  
Békefi Zsuzsanna
Keyword(s):  
Cold Hardiness ◽  
Freeze Tolerance ◽  
Phenological Stages ◽  
Climate Chamber ◽  
Cold Damage ◽  
Artificial Freezing ◽  
Delayed Development ◽  
Phenological Phases ◽  
Generative Organs

At the colder peach production regions it is important to know the cold hardiness of peach cultivars at different phenological stages of flowering. In our experiment, artificial freezing tests were conducted in a climate chamber in five selected years between the period of 2007 and 2016 to determine the freeze tolerance of generative organs of three peach cultivars (‘Venus’, ‘Redhaven’, ‘Piroska’) at different phenological stages of bloom. Based on the results of the laboratory freezing tests LT<sub>50</sub> values were calculated. Our results showed that LT<sub>50</sub> values of examined peach cultivars in swelled bud stage averaged over five years were between –6.8 and –11.2°C according to cultivar, and as phenological phases progressed, cold hardiness of generative organs decreased. At the end of bloom LT<sub>50</sub> values varied between –1.7 and –4.1°C. Cultivar ‘Piroska’ had the highest freeze tolerance and cultivar ‘Venus’ showed the lowest in each year studied. This study shows that trees with delayed development are more prone to cold damage to flowers.

scholarly journals Autumn Warming Delays the Downregulation of Photosynthesis and Does Not Increase the Risk of Freezing Damage in Interior and Coastal Douglas-fir

2021 ◽  
Vol 4 ◽  
Author(s):  
Devin Noordermeer ◽  
Vera Marjorie Elauria Velasco ◽  
Ingo Ensminger
Keyword(s):  
Cold Acclimation ◽  
Freezing Tolerance ◽  
Xanthophyll Cycle ◽  
Low Temperatures ◽  
Cold Hardiness ◽  
Photosynthetic Activity ◽  
Elevated Temperatures ◽  
Douglas Fir ◽  
The Impact ◽  
Xanthophyll Cycle Pigment

During autumn, evergreen conifers utilize the decrease in daylength and temperature as environmental signals to trigger cold acclimation, a process that involves the downregulation of photosynthesis, upregulation of photoprotection, and development of cold hardiness. Global warming will delay the occurrence of autumn low temperatures while daylength remains unaffected. The impact of autumn warming on cold acclimation and the length of the carbon uptake period of species with ranges that encompass diverse climates, such as Douglas-fir (Pseudotsuga menziesii), remains unclear. Our study investigated intraspecific variation in the effects of autumn warming on photosynthetic activity, photosynthetic pigments, and freezing tolerance in two interior (var. glauca) and two coastal (var. menziesii) Douglas-fir provenances. Following growth under simulated summer conditions with long days (16 h photoperiod) and summer temperatures (22/13°C day/night), Douglas-fir seedlings were acclimated to simulated autumn conditions with short days (8 h photoperiod) and either low temperatures (cool autumn, CA; 4/−4°C day/night) or elevated temperatures (warm autumn, WA; 19/11°C day/night). Exposure to low temperatures in the CA treatment induced the downregulation of photosynthetic carbon assimilation and photosystem II efficiency, increased the size and de-epoxidation of the xanthophyll cycle pigment pool, and caused the development of sustained nonphotochemical quenching (NPQ). Seedlings in the WA treatment exhibited no downregulation of photosynthesis, no change in xanthophyll cycle pigment de-epoxidation, and no development of sustained NPQ. Albeit these changes, freezing tolerance was not impaired under WA conditions compared with CA conditions. Interior Douglas-fir seedlings developed greater freezing tolerance than coastal seedlings. Our findings suggest that autumn warming, i.e., short photoperiod alone, does not induce the downregulation of photosynthesis in Douglas-fir. Although autumn warming delays the downregulation of photosynthesis, the prolonged period of photosynthetic activity does not bear a trade-off of impaired freezing tolerance.

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