Stomatal and Leaf Morphology Response of European Beech (Fagus sylvatica L.) Provenances Transferred to Contrasting Climatic Conditions

Abstract

Climate change-induced elevated temperatures and drought are considered to be serious threats to forest ecosystems worldwide, negatively affecting tree growth and viability. We studied nine European beech (Fagus sylvatica L.) provenances located in two provenance trial plots with contrasting climates in Central Europe. Stomata play a vital role in the water balance of plants by regulating gaseous exchanges between plants and the atmosphere. Therefore, to explain the possible adaptation and acclimation of provenances to climate conditions, stomatal (stomatal density, the length of guard cells, and the potential conductance index) and leaf morphological traits (leaf size, leaf dry weight and specific leaf area) were assessed. The phenotypic plasticity index was calculated from the variability of provenances’ stomatal and leaf traits between the provenance plots. We assessed the impact of various climatic characteristics and derived indices (e.g., ecodistance) on intraspecific differences in stomatal and leaf traits. Provenances transferred to drier and warmer conditions acclimated through a decrease in stomatal density, the length of guard cells, potential conductance index, leaf size and leaf dry weight. The reduction in stomatal density and the potential conductance index was proportional to the degree of aridity difference between the climate of origin and conditions of the new site. Moreover, we found that the climate heterogeneity and latitude of the original provenance sites influence the phenotypic plasticity of provenances. Provenances from lower latitudes and less heterogeneous climates showed higher values of phenotypic plasticity. Furthermore, we observed a positive correlation between phenotypic plasticity and mortality in the arid plot but not in the more humid plot. Based on these impacts of the climate on stomatal and leaf traits of transferred provenances, we can improve the predictions of provenance reactions for future scenarios of global climate change.

Changes in Watering Frequency Stimulate Differentiated Adaptive Responses among Seedlings of Different Beech Populations

“…These traits include stomatal number in leaves and stem anatomical traits. When watering occurred less frequently, seedlings belonging to the Evros population had a significantly lower density of stomata on their leaves, which is a typical response of beech populations when transferred to drier and warmer climates [ 32 ]. The same treatment caused the opposite trend in seedlings from Drama, which thus had increased stomatal density on their leaves when watering occurred less frequently.…”

“…Plants experiencing prolonged drought intervals between precipitation events usually respond directly to environmental stress by modifying various aspects of their phenology, physiology, morphology and/or anatomy [ 18 , 23 , 24 , 25 , 26 , 27 , 28 , 29 ]. Additionally, plant populations originating from different locations often appear to modify stomata parameters such as size or density, as a result of adaptation to the varying levels of precipitation on their original site [ 30 , 31 , 32 ].…”

“…Plasticity of morphological traits, at the population level, under environmental pressure (e.g., drought) is a common adaptive response [ 33 ]. Leaf size and shape are among the most plastic traits; in broadleaved trees, under water deficit, leaf size is reduced and leaves usually become narrower [ 32 , 34 , 35 ]. As carbon production is reduced under water deficit due to the decrease in photosynthesis rate, plants change their allometric traits such as specific leaf area (SLA), root to shoot ratio and biomass allocation, to adjust growth under the deficit pressure and ensure survival [ 36 , 37 , 38 ].…”

Investigating the Phenotypic Plasticity of the Invasive Weed Trianthema portulacastrum L.

“…Invasion success may be influenced by phenotypic plasticity and the evolution of reproductive characteristics, which are related to the seeds’ polymorphism and their dispersal behavior [ 61 ]. Accordingly, these features are required for invasive plants because they are related to dispersal tactics and systems to cope with environmental stress, maximizing their performance and establishment in the new environment [ 55 , 62 ]. This could also be related to the susceptibility of seeds to the various abiotic and biotic conditions [ 63 ].…”

Impacts of Climate Change on Tree Physiology and Responses of Forest Ecosystems

“…Based on survival rates, morphological, and physiological features, they concluded that Quercus pubescens may be a suitable candidate forest tree for poor and dry soils under the expected summer heat and drought conditions in Central Europe. In the same context, a provenance trials approach was used to evaluate nine European beech (Fagus sylvatica L.) provenances under contrasting climates [6]. An acclimation potential of provenances transferred to warmer and drier conditions was indicated by the development of smaller leaves with decreasing stomatal density and length of guard cells.…”