Geographic and seasonal variation in cold hardiness of whitebark pine

2006 ◽  
Vol 36 (7) ◽  
pp. 1842-1850 ◽  
Author(s):  
Andrew D Bower ◽  
Sally N Aitken

Artificial freeze-testing utilizing the electrolyte-leakage method was used to test the cold hardiness of 2-year-old whitebark pine (Pinus albicaulis Engelm.) seedlings growing in a common garden. Testing across all seasons was used to determine the annual pattern of cold hardiness, and more intensive sampling in the fall and spring was used to assess genetic variation in cold injury among geographic regions spanning the range of the species. Mean hardiness varied widely from –9 °C in early summer to below –70 °C in the winter. Trees from interior and northern regions were the most hardy in the fall, while trees from California were the least hardy. Geographic patterns of hardiness in the spring were reversed. Significant differences in cold injury among regions were detected on all dates except during the winter. Heritability was low to moderate for both the spring (h2 = 0.18) and the fall (h2 = 0.28), and genetic correlation was weak (rA = 0.18). Only spring cold injury was genetically correlated with date of needle flush (rA = 0.34). Mean cold injury in the fall was most closely correlated with mean temperature of the coldest month in the parental environment (r = 0.81). Whitebark pine is well adapted to the low temperatures of the harsh environments where it is found; however, regional variation indicates that moving seed for restoration purposes from areas with higher winter temperatures to colder environments may increase the chance of fall cold injury.

2003 ◽  
Vol 128 (3) ◽  
pp. 330-336 ◽  
Author(s):  
James A. Schrader ◽  
William R. Graves

Alnus maritima (Marsh.) Muhl. ex Nutt. is a large shrub or small tree with potential for use in managed landscapes. Because the three subspecies of A. maritima are indigenous only to areas with mild winter temperatures (USDA hardiness zones 7a and 7b), knowledge of their cold acclimation and cold hardiness is vital if they are to be used where winters are more harsh. Phenology and depth of cold hardiness were assessed by collecting stem samples seven times from 25 Sept. 2000 to 23 Apr. 2001, subjecting the samples to cold temperature ramping, and determining the lowest survival temperature (LST) via the tissue discoloration method. Samples were collected from indigenous plants of the three subspecies and from plants growing in a common garden near Ames, Iowa (USDA zone 5a). Results indicated that some plants from all three subspecies can survive midwinter extremes as low as -80 °C; that plants grown in Ames achieved a greater depth of cold hardiness for most of the winter and were more uniform in cold hardiness than plants growing in warmer native sites; and that the three subspecies did not differ in phenology or depth of cold acclimation. Results of field trials with plots of 150 plants each installed in three northern hardiness zones (USDA zones 5a, 4a, and 3a) supported these conclusions by showing survival of all 450 plants. We resolved differences among subspecies by rating the percentage of stem tissue survival for each plant in the field plots. Subspecies maritima, from the northernmost provenance (the Delmarva Peninsula), showed the least stem death across all three plots (3.9% tissue death), followed by subsp. georgiensis from northwestern Georgia (10% tissue death), and subsp. oklahomensis from southern Oklahoma (12.8% tissue death). Our results suggest that low temperatures should not limit the use of A. maritima in areas as harsh as USDA zone 3a. Selections based on cold hardiness may allow the use of A. maritima in areas with even colder winters.


2014 ◽  
Vol 7 (4) ◽  
pp. 624-630 ◽  
Author(s):  
Christa E. Fettig ◽  
Ruth A. Hufbauer

AbstractBlack henbane can be either annual or biennial. We investigated which life cycle is found in four introduced western North American populations. Plants were grown in a greenhouse common garden until half were vernalized by exposure to natural winter temperatures, while the other half remained in the greenhouse above 20 C, with 16 h of light and 8 h of dark. In total the plants were monitored 313 d after germination. We measured whether plants bolted, the time it took for bolting to commence, and the size at bolting. All vernalized plants bolted after 117 d of active growth (within 26 d of the end of the vernalization treatment), whereas only 26% of the nonvernalized plants bolted after an average of 278 d of active growth. Vernalized plants bolted at a smaller size than the nonvernalized plants that bolted (28 vs. 41 leaves on average). In the nonvernalized plants, the relationship between time to bolting and size was strong, but not so with the vernalized plants. Our results indicate that introduced black henbane plants are biennial, and that vernalization is more critical to bolting and flowering than reaching a certain size. Nonetheless, the fact that nonvernalized plants were capable of bolting if grown long enough suggests that vernalization is not the only cue that can trigger reproduction in introduced populations.


2009 ◽  
Vol 39 (3) ◽  
pp. 519-525 ◽  
Author(s):  
Chang-Yi Xie ◽  
Cheng C. Ying ◽  
Alvin D. Yanchuk ◽  
Diane L. Holowachuk

Genetic differentiation of black cottonwood ( Populus balsamifera subsp. trichocarpa (Torr. & A. Gray ex Hook) Brayshaw) across a “no-cottonwood” belt on the coast of central British Columbia (BC), Canada, was examined using data on 3 year height, severity of infection by Valsa sordida Nitschke and Melampsora occidentalis H. Jacks., and abnormality of leaf flushing. The data were collected in a common-garden test consisting of 180 provenances of 36 drainages ranging from northern BC to Oregon, USA. The results demonstrated an ecotypic mode, north–south regional differentiation. Valsa sordida and M. occidentalis infected 41% and 89%, respectively, of the trees from the northern region, while 66% showed flushing abnormality. In contrast, only 1% and 27% of their southern counterparts were infected by the same diseases, and 1% had abnormal flushing. Trees from the northern region averaged 87% shorter than those from the south. Regional differentiation accounted for the highest amount of variation observed in all traits, with 60% in 3 year height, 34% in V. sordida, 76% in M. occidentalis, and 50% in abnormal leaf flushing. Regression analysis revealed geographic patterns that essentially reflected regional differentiation along the no-cottonwood belt. The species’ distribution biography, ecological characteristics, and life history suggest that restricted gene migration was the main factor responsible for the observed geographic patterns of genetic differentiation.


2006 ◽  
Vol 84 (7) ◽  
pp. 1110-1121 ◽  
Author(s):  
J. Bradley St. Clair

Genetic variation in fall cold damage in coastal Douglas-fir ( Pseudotsuga menziesii (Mirb.) Franco var. menziesii ) was measured by exposing excised branches of seedlings from 666 source locations grown in a common garden to freezing temperatures in a programmable freezer. Considerable variation was found among populations in fall cold hardiness of stems, needles, and buds compared with bud burst, bud set, and biomass growth after 2 years. Variation in fall cold hardiness was strongly correlated (r = 0.67) with cold-season temperatures of the source environment. Large population differences corresponding with environmental gradients are evidence that natural selection has been important in determining genetic variation in fall cold hardiness, much more so than in traits of bud burst (a surrogate for spring cold hardiness), bud set, and growth. Seed movement guidelines and breeding zones may be more restrictive when considering genetic variation in fall cold hardiness compared with growth, phenology, or spring cold hardiness. A regional stratification system based on ecoregions with latitudinal and elevational divisions, and roughly corresponding with breeding zones used in Oregon and Washington, appeared to be adequate for minimizing population differences within regions for growth and phenology, but perhaps not fall cold hardiness. Although cold hardiness varied among populations, within-population and within-region variation is sufficiently large that responses to natural or artificial selection may be readily achieved.


2019 ◽  
Vol 25 (1) ◽  
pp. 161-167
Author(s):  
Alar Läänelaid ◽  
Samuli Helama

Tree-ring records of Sitka spruce growing in Hiiumaa (Estonia) were investigated to illustrate their growth variability and its climatic determinants. A chronology comprising ring-width series of eight big individuals from the Suuremõisa forest park was correlated with local climatic records. The growth variability of this species introduced to Hiiumaa was statistically explained profoundly by winter temperature and early-spring precipitation. Comparisons were also made with local tree-ring data of Norway spruce. Interestingly, both the native and non-native species responded positively to precipitation in June and negatively to precipitation in April. Previous studies have shown that the winter temperature response, demonstrated here for Sitka spruce, is found as Norway spruce growth responses in eastern Estonia, whereas in western Estonia the growth of the latter species is more clearly connected, similar to our findings, to early-summer precipitation. These findings indicate that while the both spruce species remain sensitive to spring/summer moisture regime, the growth of Sitka spruce may actually be less tolerate to winter temperatures, as evident here in western Estonia where the winters may likely be milder than in eastern Estonia. Common to Sitka spruce results from Hiiumaa, tree-ring data representing conspecific native populations from north-west North American sites indicated positive responses to mid-winter temperatures. Based on these results, low winter temperatures and early-summer droughts may both threaten the survival of the remnant individuals of this species in Hiiumaa.


1991 ◽  
Vol 69 (6) ◽  
pp. 1361-1371 ◽  
Author(s):  
Thomas W. H. Backman

The relation between environmental factors and leaf morphology of Zostera marina L. have long been unclear, primarily because the species is intrinsically variable. The common-garden method was used to determine the genetic, environmental, and interaction components of leaf size variation. Zostera marina consists of several ecotypes with a wide range of phenotypic plasticity. Variation in the morphology of Z. marina was of three types: genetic, accounting for 14% across the localities studied; environmental (phenotypic plasticity along temporal and spatial gradients), accounting for 32%; and interaction between genotype and environmental, acounting for 35%. Five ecotypes were described for the North American Pacific coast: Z. marina L. var. izembekensis Backman, Z. marina L. var. typica Setchell, Z. marina L. var. phillipsii Backman, Z. marina L. var. latifolia Morong, Z. marina L. var. atàm Backman. Temporal variation was due to seasonal phenotypic changes in ecotypes. Zostera marina var. izembekensis showed little seasonal morphological changes; Z. marina var. typica demonstrated minor increase in leaf size in spring and summer. Zostera marina var. phillipsii and Z. marina var. latifolia behaved similarly in that leaf size of both increased markedly in spring through early summer. Zostera marina var. phillipsii is adapted to Hood Canal and Puget Sound while Z. marina var. latifolia occupies the outer coast. Zostera marina var. atàm exhibits sexual reproduction exclusively and is specifically adapted to the Gulf of California. Key words: seagrasses, common-garden experiment, ecotypes, morphometrics, genotypes.


Horticulturae ◽  
2021 ◽  
Vol 7 (10) ◽  
pp. 379
Author(s):  
Lin Ouyang ◽  
Leen Leus ◽  
Ellen De Keyser ◽  
Marie-Christine Van Labeke

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.


HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 807E-807
Author(s):  
E.W. Stover ◽  
T.E. Paine ◽  
W.C. Stiles

Damage to xylem subtending apple buds is often observed following very low winter temperatures. Reports suggest that prebloom application of boron, zinc, and urea facilitate recovery. Prebloom nutrient treatments were applied to `McIntosh' and `Empire' at three sites in Spring 1994. The following treatments were applied to drip at half-inch green: boron (22.8 mM, solubor); Zn-EDTA (0.75 mM); boron and Zn-EDTA; boron, Zn-EDTA, and urea (59.4 mM). Another treatment used boron and Zn-EDTA at half-inch green, followed by boron, Zn-EDTA, and urea at pink. Spur leaf area, fruit set, fruit size, and seed number were determined. There were no clear treatment effects at the warmest site (mid-winter low –32C); however, this orchard was more variable than other treatment sites. The intermediate site (mid-winter low –37C) had a strong trend of increasing fruit set in `Empire' and `McIntosh' as more nutrients were applied. The combined half-inch green and pink treatment significantly increased fruit set by 23.8% compared to the untreated control. At the coldest site (mid-winter low –42C), `Empire' again displayed a strong trend of increasing fruit set with additional nutrients. All treatments combining boron and zinc significantly increased fruit set. The combined half-inch green and pink treatment increased fruit set by 43%. At this site `McIntosh' did not respond to treatment. However, `McIntosh' trees had continued active growth into late Fall 1993 and sustained severe cold injury in November. Data suggest that, when they were effective, nutrient treatments resulted in increased retention of flower buds on damaged spurs.


2021 ◽  
Author(s):  
Skye Butterson ◽  
Amanda D Roe ◽  
Katie Elizabeth Marshall

High latitude insect populations must cope with extreme conditions, particularly cold temperatures. Insects use a variety of cold hardiness mechanisms to withstand this temperature stress, and these can drive geographic distributions through overwintering mortality. The degree of cold hardiness can be altered by two evolved responses: phenotypic plasticity and local adaptation. Phenotypic plasticity can occur within or between generations (transgenerational plasticity; TGP), and local adaptation can evolve through directional selection in response to regional climatic differences. We used the eastern spruce budworm, Choristoneura fumiferana (Lepidoptera: Tortricidae) as a model to explore the role that variable winter temperatures play in inducing two aspects of plasticity in cold hardiness: TGP and local adaptation in phenotypic plasticity. This species is one of the most destructive boreal forest pests in North America, therefore accurately predicting overwintering survival is essential for effective management. While we found no evidence of TGP in cold hardiness, there was a long-term fitness cost to larvae that experienced repeated cold exposures. We also found evidence of local adaptation in both seasonal and short-term plasticity of cold hardiness. These findings provide evidence for the importance of phenotypic plasticity and local adaptation when modelling species distributions.


HortScience ◽  
2005 ◽  
Vol 40 (4) ◽  
pp. 1002C-1002
Author(s):  
Keri Jones ◽  
Sandra Reed

Hydrangea arborescens L., or smooth hydrangea, is a shrub native to the eastern United States that produces large corymbs of pure white flowers in early summer. Rated as hardy to USDA cold hardiness zone 4, it is one of the most cold-hardy members of the genus. Hydrangea involucrata Sieb. is an Asian species that produces lavender-blue flowers in midsummer. This species, which is not widely cultivated in the United States, is only rated as hardy to zone 6 to 7. The objective of this study was to hybridize H. arborescens and H. involucrata for the purpose of combining cold hardiness and flower color. Reciprocal crosses were made between H. involucrata and H. arborescens during Summer 2003. No seed were obtained when H. involucrata was used as the maternal parent. Approximately 500 seeds were collected from H. arborescen × H. involucrata hybridizations, 36 of which germinated. Several of these seedlings were extremely weak and died at a young age. The remaining eight plants have not flowered and all possess reduced growth rates. Hybridity was verified using RAPD markers and morphological comparisons of hybrids and parents.


Sign in / Sign up

Export Citation Format

Share Document