Cold in the common garden: comparative low-temperature tolerance of boreal and temperate conifer foliage (original) (raw)
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The interaction between freezing tolerance and phenology in temperate deciduous trees
Frontiers in plant science, 2014
Temperate climates are defined by distinct temperature seasonality with large and often unpredictable weather during any of the four seasons. To thrive in such climates, trees have to withstand a cold winter and the stochastic occurrence of freeze events during any time of the year. The physiological mechanisms trees adopt to escape, avoid, and tolerate freezing temperatures include a cold acclimation in autumn, a dormancy period during winter (leafless in deciduous trees), and the maintenance of a certain freezing tolerance during dehardening in early spring. The change from one phase to the next is mediated by complex interactions between temperature and photoperiod. This review aims at providing an overview of the interplay between phenology of leaves and species-specific freezing resistance. First, we address the long-term evolutionary responses that enabled temperate trees to tolerate certain low temperature extremes. We provide evidence that short term acclimation of freezing ...
HortScience
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 exother...
European Journal of Forest Research, 2014
Determining the adaptability to abiotic conditions and potential establishment success of tree species needs to be conducted before attempting to use a species in large-scale afforestation programs. In this study, the chemical and physiological performance of four Turkish red pine (Pinus brutia Ten.) provenances was investigated after exposure to artificial cold temperature treatments to determine their adaptability to cold environment for potential use in afforestation programs. Seeds were sown and raised for 24, 28, and 32 weeks and exposed to decreasing temperatures in an artificial freezer. Relative electrolyte leakage, chlorophyll fluorescence, and carbohydrate concentrations were measured to determine the variability between provenances. Results showed that diameter and height growth did not vary with origin for each of the three growth stages measured. Root electrolyte leakage values differed between provenances, confirming that cold stress was effectively causing physiological damages when plants were exposed to temperature at-15°C and below. The variability observed in the relationship between provenances and cold hardiness responses can be attributed to tree-to-tree variability within provenances and microsites conditions. There was generally no significant difference in chlorophyll fluorescence between provenances, also attributed to low genetic variation between provenances. Carbohydrate concentrations were also very variable and varied significantly among growth stages and provenances. High-altitude provenances had higher soluble carbohydrates concentrations in several cases, suggesting a relationship between altitude, soluble sugars, and cold hardiness. However, these trends were not consistent; therefore, we suggest that such hypotheses be confirmed through more comprehensive further studies. Keywords Cold hardiness Á Roots REL Á Stem REL Á Chlorophyll fluorescence Communicated by A. Weiskittel.
European Journal of Forest Research, 2016
The temperature dependence of photosynthetic parameters has been a focus of interest during recent years owing to its profound implications in the new climate scenario. Many studies have addressed the short-term responses of photosynthetic parameters to temperature change. Less attention has been given to the intraspecific variability in the biochemical parameters of photosynthesis in response to differences in growth temperature. This study explores the effects of winter harshness on the leaf traits of two evergreen tree species (Quercus ilex and Q. suber). Leaf mass per unit area (LMA) and the concentrations of fiber, nitrogen (N), soluble protein, chlorophyll and ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco) were determined in both species throughout a temperature gradient. Several photosynthetic parameters [maximum carboxylation rate (V cmax), maximum light-driven electron flux (J max), day respiration rate (R d) and relative stomatal limitation to photosynthesis] were assessed by measuring leaf response curves of net CO 2 assimilation versus intercellular CO 2 partial pressure. LMA and structural carbohydrate concentrations increased with the decrease in winter temperatures, whereas N concentrations did not show definite patterns. Chlorophyll, soluble proteins, Rubisco, V cmax and J max declined with the decrease in winter temperatures, whereas R d at a set common temperature (25°C) was higher at colder sites. Our results suggest that an increase in LMA and in the concentration of structural carbohydrates in cold environments is associated with a reduced N allocation to the photosynthetic machinery, which leads to reduced photosynthetic capacity.
Seasonal cold hardiness in maritime pine assessed by different methods
Tree Genetics & Genomes, 2014
Three screening methods-Visual scoring (V), Fluorometry (F) and relative Conductivity (C)-were used to study the genetic variation in cold hardiness among six populations of maritime pine (Pinus pinaster Ait.) comprising both Atlantic and Mediterranean conditions of origin. Freezing damage assessments were carried out in three organs-needles, stems and buds-in two seasons-spring and autumn-. Measuring F was the fastest and most easily replicated method to estimate cold hardiness, and was as reliable as V and C for predicting the species performance. In autumn there was a positive correlation between the damage measured in all three types of organs assessed, whereas in spring correlation among organs was weak. We found wide genetic variation among populations for cold hardiness in autumn, but not in spring. Within-population differences were significant (p < 0.05) no matter which organ or screening method was used. Keywords Cold hardiness-Maritime pine-Visual scoring-relative Conductivity-Fluorometry-1. INTRODUCTION Under global warming scenarios (IPCC 2007), warmer and shorter winters will occur in many regions increasing the risk of late spring and early autumn frosts. How these new conditions would affect productivity, quality and distribution of species is a question under debate (e.g. Lindner et al. 2010), as the response to cold is affected by the sensitivity of the species (Sutinen et al. 1992; Sakai and Larcher 1987). Cold hardiness, i.e. the ability of plants to withstand freezing temperatures without undergoing significant damage, display a large level of genetic variation in forest trees both among and within populations. Under common garden conditions, some populations harden in autumn more rapidly than others, depending on their origin (Díaz et al. 2009; Weng and Parker 2008), or deharden differently in spring in response to late winter and/or early spring climate conditions (Díaz et al. 2009). Differences in hardening/dehardening have been observed also between families (e.g. Darychuk et al. 2012) or clones within populations (e.g. Anekonda et al. 2000), showing the importance of cold hardiness as a selective factor in forest trees. The implications of such differences are being considered both in assisted migration programs, breeding programs or transfer guidelines for genetic materials in order to increase productivity or adaptability (e.g. Kremer et al. 2011, O'Neill et al. 2001). In most of these applications, reliable screening methods suitable for large numbers of genotypes are a bottleneck to progress in genome-wide selection programs under different climatic scenarios (Neale and Kremer, 2011). The efficiency of these methods could vary depending on the used material (populations, families, clones) from different species. Cold hardiness can be assessed by examining the freezing damages after natural frost events in field trials, but this method poses limitations related to uncontrolled conditions and lack or repeatability which in turn leads to low statistical precision for determining differences of cold hardiness among genotypes. A better solution is to subject tissue samples to different freezing temperatures under controlled conditions and to evaluate the freezing damages in those samples (Burr et al. 1990). Several alternative screening methods for cold hardiness are available (see Burr et al. (2001) and Calkins and Swanson (1990) for a review). Among them, Visual scoring (V), relative Conductivity (C) and Fluorometry (F) of plant tissue are the most used methods. Visual scoring is an efficient and fast method widely used in conifers (e.g. L'Hirondelle et al. 2006, Anekonda and Adams 2000; Aitken and Adams 1997). The tissue is allowed to develop symptoms of damage for several days after freezing before scoring the damages in discrete classes. The relative Conductivity method measures the concentration of electrolytes leaking from the plant tissues after freezing, providing objective and quantitative results two days after the freezing treatment. The relative Conduc
Methods for Measuring Frost Tolerance of Conifers: A Systematic Map
Forests, 2021
Frost tolerance is the ability of plants to withstand freezing temperatures without unrecoverable damage. Measuring frost tolerance involves various steps, each of which will vary depending on the objectives of the study. This systematic map takes an overall view of the literature that uses frost tolerance measuring techniques in gymnosperms, focusing mainly on conifers. Many different techniques have been used for testing, and there has been little change in methodology since 2000. The gold standard remains the field observation study, which, due to its cost, is frequently substituted by other techniques. Closed enclosure freezing tests (all non-field freezing tests) are done using various types of equipment for inducing artificial freezing. An examination of the literature indicates that several factors have to be controlled in order to measure frost tolerance in a manner similar to observation in a field study. Equipment that allows controlling the freezing rate, frost exposure t...
Frontiers in Plant Science, 2015
Climate change will increase autumn air temperature, while photoperiod decrease will remain unaffected. We assessed the effect of increased autumn air temperature on timing and development of cold acclimation and freezing resistance in Eastern white pine (EWP, Pinus strobus) under field conditions. For this purpose we simulated projected warmer temperatures for southern Ontario in a Temperature Free-Air-Controlled Enhancement (T-FACE) experiment and exposed EWP seedlings to ambient (Control) or elevated temperature (ET, 1.5 • • +