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İstanbul Üniversitesi-Cerrahpaşa (2021)

Ecophysiological reactions to drought stress of stone pine (Pinus pinea L.) populations in Turkey

BALEKOĞLU Safa

Titre : Ecophysiological reactions to drought stress of stone pine (Pinus pinea L.) populations in Turkey

Türkiye’deki doğal fıstıkçamı (Pinus pinea L.) populasyonlarının kuraklığa karşı ekofizyolojik reaksiyonları

Auteur : BALEKOĞLU Safa

Université de soutenance : İstanbul Üniversitesi-Cerrahpaşa

Grade : Doiktora Tezi 2021

Résumé partiel
Stone pine (Pinus pinea L.) grown in the Mediterranean ecosystem is one of Turkey’s five major natural pine species. In addition to fruit production, it is frequently grown in areas with different ecological conditions for various purposes. Summer drought is referred as the most important factor limiting the production, growth, development and distribution of plants in Mediterranean ecosystems. In this study, it was aimed to determine the physiological and biochemical responses to summer drought in pine populations located in different geographical regions in Turkey against and to reveal the variation within the populations. Also, it was aimed to explain the relationship between these variations and bioclimatic characteristics. Research findings revealed that ΨTLP (osmotic potential at turgor loss point), RWCTLP (relative water content at turgor loss point) and ε (modulus of elasticity) parameters obtained from P-V analyzes performed to determine the water stress resistance and plasmolysis threshold values in ecological and physiological driest stage (June-July-August) showed statistically significant differences. In the analyzes performed to determine summer embolism and cavitation resistance, it was found that the P50 (the xylem pressure at 50% loss of hydraulic conductivity) value did not show significant variation among the populations while PRWL25 (the pressure application resulting in 25% of relative water loss) value was found to be statistically significant within populations. The populations ; • Yatağan (Muğla) – Koçarlı (Aydın) – Kozak (İzmir), • Önsen (K.Maraş) – Çoruh (Artvin), • Kalenema (Trabzon), • Kirazlı (Çanakkale) were grouped in four different groups. The drought conditioning process was applied at the stress level of -3.24 MPa and -2.44 MPa corresponding to 10-40% of the hydraulic conductivity of stone pine. It was found that the most significant parameter reflecting the variation between populations is ΔΨMD (ΔΨMD = mean ΨMD Well-watered – mean ΨMD Drought). The ΔΨMD values of Önsen (K.Maraş), Yatağan (Muğla), Koçarlı (Aydın), Kozak (İzmir), Çoruh (Artvin), Kalenema (Trabzon) ve Kirazlı (Çanakkale) populations were determined as -2.03 MPa, -2.38 MPa, -1.72 MPa, -1.47 MPa, -1.58 MPa, -1.42 MPa, -1.13 MPa, respectively. Also, ΔΨMD is a parameter used to determine the level of drought avoidance (isohydric). Populations from highest to lowest according to degree of isohydric ; • Kirazlı (Çanakkale), • Koçarlı (Aydın) – Çoruh (Artvin) – Kozak (İzmir) – Kalenema (Trabzon), • Önsen (K.Maraş), • Yatağan (Muğla) were grouped in four different groups. Considering that the mortality due to water deficit in the Mediterranean climate regime and semi-arid areas occur mostly in isohydric species and that tree species avoiding drought will not be safe at severe drought or water deficiency levels, it can be said that Kirazlı (Çanakkale) population is the most risky population. In this study, it was revealed that drought conditioning and rewatering applications performed on stone pine seedlings caused significant changes in soluble sugar, starch, NSC, photosynthetic pigment, proline, MDA and H2O2 contents in needle, shoot, stem and root

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Page publiée le 9 janvier 2023