The eastern‐Mediterranean Abies taxa, which include both widely distributed species and taxa with minuscule ranges, represent a good model to study the impacts of range size and fragmentation on the levels of genetic diversity and differentiation. To assess the patterns of genetic diversity and phylogenetic relationships among eastern‐Mediterranean Abies taxa, genetic variation was assessed by eight nuclear microsatellite loci in 52 populations of Abies taxa with a focus on those distributed in Turkey and the Caucasus. Both at the population and the taxon level, the subspecies or regional populations of Abies nordmanniana s.l. exhibited generally higher allelic richness, private allelic richness, and expected heterozygosity compared with Abies cilicica s.l. Results of both the structure analysis and distance‐based approaches showed a strong differentiation of the two A. cilicica subspecies from the rest as well as from each other, whereas the subspecies of A. nordmanniana were distinct but less differentiated. ABC simulations were run for a set of scenarios of phylogeny and past demographic changes. For A. ×olcayana, the simulation gave a poor support for the hypothesis of being a taxon resulting from a past hybridization, the same is true for Abies equi‐trojani: both they represent evolutionary branches of Abies bornmuelleriana.

In this study, the genetic variation in populations of Scots pine (Pinus sylvestris L.), one of the species covering large areas in Turkey, was investigated. Open pollinated seeds were collected from 11 populations in a natural distribution range. Six characters of seeds (length, width, ratio of length to width, weight/1000 seeds) and seedling (cotyledon number and hypocotyls height) and two enzyme systems (leucine aminopeptidase, LAP; glutamate oxaloacetate transaminase, GOT) were investigated. Significant differences were detected among the populations for the morphological characters. In addition, isozyme patterns of the two enzyme systems revealed that Lap has two loci (one with 2 alleles and the other with 3), while Got has three loci (two with 3 alleles and the third one with 2 alleles). Polymorphic loci were 80% on the average. The mean number of alleles per locus was 2.02, and expected heterozygosity was 22%. The mean total genetic diversity was calculated as 0.235; the mean gene diversity within populations was determined as 0.220, and the average between-subpopulation diversity was 0.014. Averaged genetic distance was 0.081. According to the genetic distance, population number 2 was separated from the remaining populations.

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Four-year-old seedlings of Abies fraseri [(Pursh) Poir] (fraser fir) were grown in semicontrolled conditions in hoop houses with five watering regimes (0.00, 0.62, 1.25, 2.50, and 3.70 cm/week) with the goal of determining the seasonal variation in the physiological response to drought stress. Drought stress was monitored by measuring predawn (Ψpd) and midday (Ψmd) potentials in a subset of plants from each treatment. Physiological variables monitored were chlorophyll fluorescence (Fv/Fm), Chl a, Chl b, total carotenes, and total carbohydrate concentrations. Morphological characteristics including height growth, root collar diameter, and terminal shoot growth were also measured. Predawn stem water potential values were generally higher (–0.8 to –1.9 Mpa) than midday values (–1.3 to –2.9 Mpa). Irrigation consistently increased Ψpd and Ψmd compared with non-irrigated treatments. Photosynthetic pigments (Chl a, Chl b, and carotenes) decreased midseason (14 July) and increased toward the end of the season (25 Aug.) in predawn and midday measurements. There was a significant effect (P < 0.05) of drought stress on photosynthetic pigment concentrations in predawn and midday samples in the late-season measurements (25 Aug.). These results were accompanied with a similar significant difference in Fv/Fm between non-irrigated and irrigated trees. We concluded that significant effects observed on photosynthetic pigment concentrations in some of the treatments did not affect carbohydrate concentrations. Exposure of A. fraseri to water stress did not cause a reduction in supply of metabolic carbohydrates; consequently, the decline and mortality in water-stressed plants can only be the result of hydraulic failure caused by xylem cavitation leading to cessation of water flow in tissues, desiccation, and cellular death. Further studies are needed to confirm these preliminary conclusions.

Za razumijevanje genetske strukture populacija šumskog drveća potrebno je poznavati genetsku varijabilnost. Razvoj izoenzimske tehnike olakšao je određivanje genetske strukture populacija u području rasprostranjenja vrsta. Određivanjem genetske strukture i varijabilnosti Picea orientalis (L.) Link, koja je u svijetu ograničena na manje područje, transfer trenutne genetske strukture na buduće generacije putem održivog gospodarenja šumama važan je za osiguravanje kontinuiteta vrste. U ovom istraživanju određene su genetske različitosti i sličnosti za populacije P. orientalis u odabranim populacijama (Artvin, Torul-Örümcek, Tirebolu-Ak&#305;lbaba, Ordu-Çambaş&#305;, Artvin-Şavşat, Ardanuç-Ovac&#305;k, Şavşat-Sahara, Artvin-Saçinka, Ardahan-Posof an Maçka-Hamsiköy) Turske. Korišteno je 10 genskih lokusa u različitim enzimskim sustavima, a određena je genetska varijabilnost, vrijednost heterozigotnost (H_o), broj alela po lokusu (A_L), genetski diverzitet (v), intrapopulacijska diferencijacija (d_T), multilokusna raznolikost (V_gam) te diferencijacija među populacijama (Dj). Za promatranu heterozigotnost, broj alela po lokusu i genetski diverzitet dobivena je središnja vrijednost od 0.154, 1.74 i 1.719. Nadalje, kod razmatranja genetskog diverziteta, pojavile su se tri različite skupine u smislu odabranih populacija. S obzirom da je populacija Torul-Örümcek pokazala relativno više vrijednosti u odnosu na ostale populacije, ova populacija je vrlo važna za održivost genetskih izvora kavkaske smreke .

The present note presents and explains the results of a study dealing with the germination of seeds subjected to heat. Seeds of Scots pine (Pinus sylvestris L.) and Anatolian black pine (Pinus nigra ssp. pallasiana) were exposed to a range of temperatures (70, 90, 110, 130, and 150°C) for different exposure times (1 and 5 min). Germination rates were similar for all treatments and control at 1 min exposure for Anatolian black pine seeds, and almost no germination took place for all treatments at 5 min exposure. Similar results were obtained for Scots pine seeds, with the exception of a sharp decrease in the number of seeds germinated above 110°C. The effect of increasing the exposure time to 5 min was immediate, and no germination took place above 90°C. Results obtained indicate that seeds of the two species do not necessarily need fire for successful regeneration, but fires may have a positive effect on the germination by removing crown cover, thereby providing more light for the seeds deposited to the ground.

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