Analysis of the functional traits of some Quercus species under different ecological conditions in Azerbaijan

Given the ecological importance of forests in combating global warming, there has been increasing attention in recent years to researching Quercus species for their ability to withstand drought. The study presented here was conducted to assess the impacts of various water conditions on the functional aspects and genetic diversity of oak species. We compared four Quercus species [Quercus petraea ssp. iberica (Stev.), Q. macranthera ssp. macranthera (K.Koch) Menitsky, Q. castaneifolia C.A.Mey., Q. robur ssp. pedunculiflora (K.Koch) Menitsky] in different sites of Azerbaijan. Thus, five functional traits (relative water content (RWC), water content (WC), leaf mass per unit area (LMA), specific leaf area (SLA), and succulence (S) related to drought tolerance were measured. Then, cluster analysis based on these functional traits was conducted, and the Euclidean genetic distance index was determined. As the temperature increases and the amount of precipitation decreases, plants are exposed to drought stress, which is accompanied by a decrease in RWC, WC, SLA and S. In contrast, an increase in LMA was observed. This response of the plant to changing environmental conditions reflects the activation of a protective mechanism; the plant is fighting for survival. The conducted analyses reveal significant genetic diversity among oak genotypes, which is formed under the influence of ecological adaptation, geographical distribution, and evolutionary processes.