Seed, germination, and seed-reserve traits differ along an altitudinal gradient

Turkish red pine (Pinus brutia Ten.), an important pine species for afforestation studies, grows at a wide range of altitudes in the eastern Mediterranean area. Seeds from low (0–400 m a.s.l.), mid (400–800 m) and high (800–1000 m) altitudinal gradients were collected to assess the effects of these gradients on morphological traits (seed length, seed width, 100-seed weight), germination variables (germination percentage and mean germination time), and 10 biochemical variables related to seed reserves. Relationships among these variables were examined with a correlation analysis. Seeds from low and high altitudes had significantly higher 100-seed weight, higher percentage germination but longer germination times and higher total oil and reducing sugars contents. Seeds from mid altitudes had higher carotenoid and soluble phenolics contents. Among the examined biochemical variables, only flavonoid content did not differ among the altitude gradients. The main fatty acids in seeds samples (linoleic, oleic, palmitic and stearic acids) were also influenced by the altitude gradients. Oil and total reducing sugars contents were positively correlated with germination percentage, and carotenoid content was negatively correlated with germination percentage. Our results confirmed that seed and germination variables, including the reserve composition varied significantly among the altitudinal gradients.