scholarly journals Mechanical basis for thermonastic movements of cold-hardy Rhododendron leaves

2020 ◽  
Vol 17 (164) ◽  
pp. 20190751
Author(s):  
Hailong Wang ◽  
Erik T. Nilsen ◽  
Moneesh Upmanyu
Keyword(s):  
Drought Resistance ◽  
Cold Hardiness ◽  
Critical Level ◽  
Cold Climates ◽  
Leaf Rolling ◽  
Leaf Movements ◽  
Mechanical Basis ◽  
Cold Hardy ◽  
Differential Expansion ◽  
Theoretical Analyses

The profusion of rhododendrons in cold climates is as remarkable as the beauty of their blooms. The cold-hardiness of some of the montane species is in part due to reversible leaf movements triggered under frigid conditions wherein the leaves droop at the leaf stalks (petioles) and their margins roll up around the midrib. We probe the mechanics of these movements using leaf dissection studies that reveal that the through-thickness differential expansion necessary for leaf rolling is anisotropically distributed transverse to and along the midrib. Numerical simulations and theoretical analyses of bilayer laminae show that the longitudinal expansion amplifies the transverse rolling extent. The curvature diversion scales with the in-plane Poisson’s ratio, suitably aided by the stiff midrib that serves as a symmetry breaking constraint that controls the competition between the longitudinal and transverse rolling. Comparison of leaf rolling with and without the petiole indicates that the petiole flexibility and leaf rolling are in part mechanically coupled responses, implicating the hydraulic pathways that maintain the critical level of midrib stiffness necessary to support the longitudinal expansion. The study highlights the importance of curvature diversion for efficient nastic and tropic leaf movements that enhance cold-hardiness and drought resistance, and for morphing more general hinged laminae.

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.

scholarly journals Super Cooling Point Phenotypes and Cold Resistance in Hyles euphorbiae Hawk Moths from Different Climate Zones

Diversity ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 207
Author(s):  
Hana Daneck ◽  
Matthias Benjamin Barth ◽  
Martin Geck ◽  
Anna K. Hundsdoerfer
Keyword(s):  
Environmental Conditions ◽  
Cold Hardiness ◽  
Cold Treatment ◽  
Underlying Mechanism ◽  
Frost Tolerance ◽  
Cold Sensitivity ◽  
Cold Hardy ◽  
Hyles Euphorbiae

The spurge hawkmoth Hyles euphorbiae L. (Sphingidae) comprises a remarkable species complex with still not fully resolved taxonomy. Its extensive natural distribution range covers diverse climatic zones. This predestinates particular populations to cope with different local seasonally unfavorable environmental conditions. The ability of the pupae to overcome outer frosty conditions is well known. However, the differences between two main ecotypes (‘euphorbiae’ and ‘tithymali’) in terms of the inherent degree of frost tolerance, its corresponding survival strategy, and underlying mechanism have not been studied in detail so far. The main aim of our study was to test the phenotypic exhibition of pupae (as the relevant life cycle stadia to outlast unfavorable conditions) in response to combined effects of exogenous stimuli, such as daylight length and cooling regime. Namely, we tested the turnout of subitan (with fast development, unadapted to unfavorable conditions) or diapause (paused development, adapted to unfavorable external influences and increased resistance) pupae under different conditions, as well as their mortality, and we measured the super cooling point (SCP) of whole pupae (in vivo) and pupal hemolymph (in vitro) as phenotypic indicators of cold acclimation. Our results show higher cold sensitivity in ‘tithymali’ populations, exhibiting rather opportunistic and short-termed cold hardiness, while ‘euphorbiae’ produces a phenotype of seasonal cold-hardy diapause pupae under a combined effect of short daylight length and continuous cold treatment. Further differences include the variability in duration and mortality of diapause pupae. This suggests different pre-adaptations to seasonal environmental conditions in each ecotype and may indicate a state of incipient speciation within the H. euphorbiae complex.

Current state of cold hardiness research on fruit crops

1997 ◽  
Vol 77 (3) ◽  
pp. 399-420 ◽  
Author(s):  
Pauliina Palonen ◽  
Deborah Buszard
Keyword(s):  
Cold Hardiness ◽  
Cultural Practices ◽  
Limiting Factor ◽  
Screening Methods ◽  
Fruit Crops ◽  
Factors Affecting ◽  
Fruit Species ◽  
Current State ◽  
Deep Supercooling ◽  
Cold Hardy

This article gives an overview of the current state of cold hardiness research in fruit crops by reviewing the recently published studies on cold hardiness of both tree fruit and berry crops. Topics discussed include cold hardiness of fruit species, cultivars and different plant organs, biophysical and biochemical aspects of hardiness, evaluation of hardiness, as well as endogenous, cultural and environmental factors affecting cold hardiness in these species. Lack of cold hardiness is a major limiting factor for production of fruit crops in many regions of the world and improved cold hardiness one of the major objectives in numerous breeding programs and research projects. Screening cultivars or selections for cold hardiness is commonly done, and different methods applied to the evaluation of hardiness are discussed. The physical limit of deep supercooling may be a restricting factor for expanding the production of some fruit crops, such as Prunus species and pear. As for biochemical aspects, a relationship between carbohydrates and cold hardiness is most commonly found. Studies have also been made on different hardiness modifying cultural factors including rootstock, crop load, raised beds and application of growth regulators. The latter seems promising for some species. Cold hardiness is an extremely complex phenomenon and understanding different mechanisms involved is critical. Since hardiness is, however, primarily affected by genotype, developing cold-hardy fruit cultivars and effective screening methods for hardiness are essential. Finally, cultural practices may be improved to further enhance hardiness. Key words: Berries, cold hardiness, fruits, small fruits, stress, winter hardiness

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.

COLD HARDINESS IN HEXAPLOID TRITICALE

1985 ◽  
Vol 65 (3) ◽  
pp. 487-490 ◽  
Author(s):  
A. E. LIMIN ◽  
J. DVORAK ◽  
D. B. FOWLER
Keyword(s):  
Cold Hardiness ◽  
Tetraploid Wheat ◽  
Triticum Aestivum L ◽  
Hexaploid Triticale ◽  
D Genome ◽  
Potential Source ◽  
Secale Cereale L ◽  
Cold Hardy ◽  
Triticosecale Wittmack ◽  
X Triticosecale Wittmack

The excellent cold hardiness of rye (Secale cereale L.) makes it a potential source of genetic variability for the improvement of this character in related species. However, when rye is combined with common wheat (Triticum aestivum L.) to produce octaploid triticale (X Triticosecale Wittmack, ABDR genomes), the superior rye cold hardiness is not expressed. To determine if the D genome of hexaploid wheat might be responsible for this lack of expression, hexaploid triticales (ABR genomes) were produced and evaluated for cold hardiness. All hexaploid triticales had cold hardiness levels similar to their tetraploid wheat parents. Small gains in cold hardiness of less than 2 °C were found when very non-hardy wheats were used as parents. This similarity in expression of cold hardiness in both octaploid and hexaploid triticales indicates that the D genome of wheat is not solely, if at all, responsible for the suppression of rye cold hardiness genes. There appears to be either a suppressor(s) of the rye cold hardiness genes on the AB genomes of wheat, or the expression of diploid rye genes is reduced to a uniform level by polyploidy in triticale. The suppression, or lack of expression, of rye cold hardiness genes in a wheat background make it imperative that cold-hardy wheats be selected as parents for the production of hardy triticales.Key words: Triticale, Secale, winter wheat, cold hardiness, gene expression

How aquatic insects live in cold climates

2007 ◽  
Vol 139 (4) ◽  
pp. 443-471 ◽  
Author(s):  
H. V. Danks
Keyword(s):  
Aquatic Insects ◽  
Cold Hardiness ◽  
Life Cycles ◽  
Cold Climate ◽  
Cold Climates ◽  
Aquatic Habitats ◽  
Biochemical Basis ◽  
Terrestrial Habitats ◽  
One Year ◽  
Different Parts

AbstractIn cold climates most aquatic habitats are frozen for many months. Nevertheless, even in such regions the conditions in different types of habitat, in different parts of one habitat, and from one year to the next can vary considerably; some water bodies even allow winter growth. Winter cold and ice provide challenges for aquatic insects, but so do high spring flows, short, cool summers, and unpredictable conditions. General adaptations to cope with these constraints, depending on species and habitat, include the use of widely available foods, increased food range, prolonged development (including development lasting more than one year per generation), programmed life cycles with diapause and other responses to environmental cues (often enforcing strict univoltinism), and staggered development. Winter conditions may be anticipated not only by diapause and related responses but also by movement for the winter to terrestrial habitats, to less severe aquatic habitats, or to different parts of the same habitat, and by construction of shelters. Winter itself is met by various types of cold hardiness, including tolerance of freezing in at least some species, especially chironomid midges, and supercooling even when surrounded by ice in others. Special cocoons provide protection in some species. A few species move during winter or resist anoxia beneath ice. Spring challenges of high flows and ice scour may be withstood or avoided by wintering in less severe habitats, penetrating the substrate, or delaying activity until after peak flow. However, where possible species emerge early in the spring to compensate for the shortness of the summer season, a trait enhanced (at least in some lentic habitats) by choosing overwintering sites that warm up first in spring. Relatively low summer temperatures are offset by development at low temperatures, by selection of warm habitats and microhabitats, and in adults by thermoregulation and modified mating activity. Notwithstanding the many abiotic constraints in cold climates, aquatic communities are relatively diverse, though dominated by taxa that combine traits such as cold adaptation with use of the habitats and foods that are most widely available and most favourable. Consequently, except in the most severe habitats, food chains and community structure are complex even at high latitudes and elevations, including many links between aquatic and terrestrial habitats. Despite the complex involvement of aquatic insects in these cold-climate ecosystems, we know relatively little about the physiological and biochemical basis of their cold hardiness and its relationship to habitat conditions, especially compared with information about terrestrial species from the same regions.

Mefluidide-induced drought resistance in seedlings of three conifer species

1993 ◽  
Vol 71 (8) ◽  
pp. 1087-1092
Author(s):  
Salim N. Silim ◽  
Robert D. Guy ◽  
Denis P. Lavender
Keyword(s):  
Abscisic Acid ◽  
Stomatal Conductance ◽  
Plant Growth ◽  
Drought Resistance ◽  
Picea Glauca ◽  
Cold Hardiness ◽  
Net Photosynthesis ◽  
Thuja Plicata ◽  
Red Cedar ◽  
Thuja Plicata Donn

Short-term effects of the plant growth retardant mefluidide on drought resistance were investigated in seedlings of western red cedar (Thuja plicata Donn), yellow cedar (Chamaecyparis nootkatensis D. Don), and white spruce (Picea glauca (Moench) Voss). Mefluidide was applied as a root drench at concentrations of 0, 0.1, and 0.4 mg∙L−1. Following this, seedlings were stressed by withholding water for a period of up to 7 days and then watering regularly thereafter. Stomatal conductance of the mefluidide-treated seedlings decreased significantly and remained lower than the control seedlings throughout the stress period. As a result of the decreased conductance, shoot water potentials in mefluidide-treated seedlings remained higher throughout the stress period. There was a decrease in net photosynthesis that was partially caused by stomatal limitations, the severity of which depended upon the concentration of mefluidide applied. Mefluidide treatment also resulted in an accumulation of abscisic acid in all three species, and this may have been responsible for the effects on stomatal conductance and water relations. In contrast, the mefluidide-treated seedlings had the highest rates of photosynthesis after rewatering, resulting primarily from a promotion of stomatal opening. Key words: stomatal conductance, water potential, photosynthesis, plant growth inhibitors, abscisic acid, cold hardiness.

scholarly journals Dehydrins and Soluble Sugars Involved in Cold Acclimation of Rosa wichurana and Rose Cultivar ‘Yesterday’

Horticulturae ◽  
2021 ◽  
Vol 7 (10) ◽  
pp. 379
Author(s):  
Lin Ouyang ◽  
Leen Leus ◽  
Ellen De Keyser ◽  
Marie-Christine Van Labeke
Keyword(s):  
Cold Acclimation ◽  
Cold Hardiness ◽  
Prolonged Exposure ◽  
Sugar Content ◽  
Soluble Sugar ◽  
Soluble Sugars ◽  
Winter Season ◽  
Sugar Metabolism ◽  
Northern Regions ◽  
Cold Hardy

Rose is the most economically important ornamental plant. However, cold stress seriously affects the survival and regrowth of garden roses in northern regions. Cold acclimation was studied using two genotypes (Rosa wichurana and R. hybrida ‘Yesterday’) selected from a rose breeding program. During the winter season (November to April), the cold hardiness of stems, soluble sugar content, and expression of dehydrins and the related key genes in the soluble sugar metabolism were analyzed. ‘Yesterday’ is more cold-hardy and acclimated faster, reaching its maximum cold hardiness in December. R. wichurana is relatively less cold-hardy, only reaching its maximum cold hardiness in January after prolonged exposure to freezing temperatures. Dehydrin transcripts accumulated significantly during November–January in both genotypes. Soluble sugars are highly involved in cold acclimation, with sucrose and oligosaccharides significantly correlated with cold hardiness. Sucrose occupied the highest proportion of total soluble sugars in both genotypes. During November–January, downregulation of RhSUS was found in both genotypes, while upregulation of RhSPS was observed in ‘Yesterday’ and upregulation of RhINV2 was found in R. wichurana. Oligosaccharides accumulated from November to February and decreased to a significantly low level in April. RhRS6 had a significant upregulation in December in R. wichurana. This study provides insight into the cold acclimation mechanism of roses by combining transcription patterns with metabolite quantification.

scholarly journals 561 PB 406 THE EFFECTS OF COLD TEMPERATURES ON THE SURVIVABILITY AND POST-STRESS PERFORMANCE OF CONTAINER-GROWN NURSERY STOCK

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 512a-512
Author(s):  
Jennifer L. Dwyer ◽  
N. Curtis Peterson ◽  
G. Stanley Howell
Keyword(s):  
Cold Hardiness ◽  
Winter Hardiness ◽  
Cold Temperatures ◽  
Woody Ornamentals ◽  
Nursery Stock ◽  
Cold Hardy ◽  
Improved Methods ◽  
Post Stress

The nursery industry continues to develop improved methods for successfully overwintering container-grown nursery stock. Experiments were conducted using several different species of woody ornamentals ranging from species known to be cold hardy to cold tender. Eighteen species were subjected to temperatures ranging from 20F to -20F and observed for post-stress performance and viability. Rates and timing of acclimation, mid-winter hardiness, and deacclimation of seven species were determined by examining the shoots for injury after subjecting them to controlled freezer conditions. The roots of the same seven species were exposed to three different overwintering systems: in a polyhouse, pot-to-pot above the ground, and pot-in-pot below the ground. Cold hardiness of root and shoot systems and the effects of warming temperatures on shoots were determined as well as the post-stress performance of each species. Results of this research will be presented.

scholarly journals Cold Hardiness of Evergreen Azaleas Increased by Water Stress Imposed at Three Days

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 848E-848
Author(s):  
Tomasz Anisko ◽  
Orville M. Lindstrom
Keyword(s):  
Water Stress ◽  
Water Supply ◽  
Water Potential ◽  
Cold Hardiness ◽  
Plant Parts ◽  
Effect Of Water ◽  
Cold Hardy ◽  
Reduced Water

The effect of water stress on cold hardiness was examined in evergreen azaleas, `Coral Bell' (CB), `Hinodegiri' (HD), and `Red Ruffle' (RR). Plants were well-watered between 8 Aug. and 1 Nov. (wet) or were subjected to 3 weeks of reduced water supply starting on one of three dates, 1 Aug. (dry 1), 29 Aug. (dry 2), and 19 Sept. (dry 3). Cold hardiness of leaves and lower, middle, and upper stems was tested on 29 Aug., 19 Sept., 10 Oct., 1 Nov. By the end of each 3-week period, water potential of water stressed plants reached –1.5 to –1.8 MPa compared to around –0.8 MPa of well-watered plants. Reducing the water supply significantly increased cold hardiness of all tested plant parts in all cultivars regardless of timing of watering reduction, with two exceptions, CB middle stems on 29 Aug. and HD leaves on 19 Oct. Three weeks after rewatering cold hardiness of water-stressed plants did not differ significantly from well-watered plants, except for HD plants under dry three treatment, which continued to be 1.0 (middle stems) to 4.3 (upper stems) more cold hardy.

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