Intraspecific variability in cold tolerance in Pinus brutia sampled from two contrasting provenance trials

Abstract

Turkish red pine (Pinus brutia Ten.), is the most important tree species for afforestation in the Mediterranean basin due to its drought tolerance and fast growth rate. Cold damage to trees caused by harsh winter conditions is common on many sites in Turkey. Adaptation to climate change has been investigated primarily through the movement of species from warmer and drier climates, such as the Mediterranean P. brutia, to higher latitudes and cooler sites in central-north Turkey. In order to better guide species and provenances movement to new (and often harsh) environments for afforestation, the limits of tolerance to cold and drought should be better known. Thus, we designed an experiment to quantify the cold hardiness of nine P. brutia provenances originating from two different provenance trials in Turkey (Ankara, cold inner site; Antalya, warm Mediterranean site). Branches sampled at the end of January were exposed to cold temperatures between − 5 and − 40 °C. Visual damage observation, relative electric leakage and chlorophyll fluorometry (CF) screening methods were used to assess variation in cold hardiness among populations. Overall, P. brutia can tolerate winter temperatures up to − 16 °C. Even though there were significant differences on cold hardiness among populations, the operational application is limited due to the reduced magnitude of those differences. Measuring CF was the fastest and most easily replicated method to estimate cold hardiness and was as reliable as REL. We recommend that P. brutia should not be planted in cold areas where minimum annual temperatures are under − 16 °C. We also conclude that even though phenotypic plasticity exists for cold hardiness among the tested populations of P. brutia, the observed differences resulted from acclimation to the conditions of the provenance trial sites rather than from adaptation through natural selection.

Freezing and Heating Tolerance of Pinus nigra Seedlings from Three South to North Balkan Provenances

“…The two methods used, in the current study, to assess frost hardiness of P. nigra seedlings showed quite similar results, indicating that for all studied provenances the damage was great; the index of injury (Ii) at −18 • C was ranged from 49 to 54.5 (measured by EC method) and the percentage of injured tissues ranged from 80-90% (measured by visual observation). Similarly, Semerci et al [19], who studied frost damages in P. brutia seedlings from various provenances of two contrasting sites (north-south), found similar results from the electrical conductivity and visual observation methods. For P. nigra seedlings from all studied provenances, a sharp increase in damages was observed with the fall of temperature from −5 and −18 • C, and the time exposure to it.…”

“…Frost hardiness testing consists of subjecting of seedlings or parts thereof to freezing temperatures and evaluation of the treatment effects [11]. For the estimation of frost hardiness of the studied provenances of black pine, two commonly used tests were selected to be applied in the seedlings produced in the nursery: EC test, and whole-plant freeze testing (WPFT) [11,19]. Sampling for both tests took place in the first week of October 2018.…”

Adaptation of Mediterranean forest species to climate: Lessons from common garden experiments

“…low LT 50 ) and provenance minimum temperature of the coldest month (Table 1). A recent study on P. brutia has also revealed significant differences in cold tolerance among populations and, although it did not explore its association with provenance climate, it also revealed that acclimation to increasingly cold experimental temperatures strongly differed among populations (Semerci et al., 2020).…”

Examining Seed Germination Rate and Seedlings Gas Exchange Performances of Some Turkish Red Pine Provenances Under Water Stress

“…Turkish red pine (Pinus brutia Ten.) naturally occurs in a wide range of the Eastern Mediterranean region, from sea level to 1600 meters altitude and covering roughly 5.6 million ha of natural forest areas in Turkey [1,2]. Turkish red pine is a light-demanding, fast-growing, and drought-tolerant conifer species due to a deep tap-rooting system [3], and approximately 52.5 million seedlings of Turkish red pine were produced across the country in 2015 [4].…”

“…This species is the most critical forest tree species in Turkish forestry owing to its ability to grow in unfavorable environments such as calcareous, dry, and poor soil conditions [4,5]. Also, this species is widely used for various purposes such as afforestation, plantation, and recreation due to a high ecologically and economically crucial roles in arid and semiarid areas in Turkey [1,6,7].…”