Comparative analyses of gas exchange characteristics and chlorophyll fluorescence of three dominant tree species during the vegetation season in hemi-boreal zone, Lithuania

Abstract

Current climate scenarios predict rising air temperature along with increasing frequency and intensity of summer drought in the Central and Eastern Europe. Severe drought episodes affect physiological processes in trees such as transpiration, photosynthesis and carbon allocation. Understanding gas exchange between plants and the atmosphere is important in woody plant research. The aim of this study was to evaluate differences in gas exchange characteristics and chlorophyll fluorescence of tree species prevailing in Lithuania Scots pine, Norway spruce and Silver birch and their physiological response to water stress. The study was conducted in Aukstaitija integrated monitoring station, Lithuania. Gas exchange parameters and chlorophyll fluorescence were measured during the vegetation season of 2016. Meteorological parameters were obtained from the monitoring station. Four weather periods with different meteorological conditions were identified. Under moderate drought conditions all investigated tree species demonstrated reduced photosynthetic rates, lower stomatal conduction transpiration rates, water use efficiency and instantaneous carboxylation efficiency. During moderate drought, intercellular CO 2 concentration of Norway spruce was higher and this species demonstrated the highest decrease in instantaneous carboxylation efficiency. No significant changes of maximal chlorophyll fluorescence Fv/Fm among species were detected during different weather periods except Silver birch. The investigated tree species reacted differently to weather conditions. The Scots pine demonstrated the highest tolerance to different weather conditions. The study confirmed the sensitivity of Norway spruce to drought conditions. The Silver birch was the least sensitive to temperature and humidity conditions variation.

Respuestas de los atributos fotosintéticos y estequiométricos a la aridez en las especies y tipos funcionales de dos comunidades del desierto sonorense

“…Efecto de la aridez en los atributos relacionados a la efi ciencia en el uso del agua. Es ampliamente conocido que la UEA, tiene una fuerte relación con la aridez, tanto a nivel global como nivel comunidad (Ito & Inatomi 2012, Nolan et al 2018, Marozas et al 2019, y es considerado un atributo económico crítico para las plantas en comunidades áridas (Ávila-Lovera et al 2019). Debido a esto, se esperaba encontrar, en promedio, mayor UEA (UEA inst y UEA intrins ) en las especies del sitio con mayor aridez, pero está diferencia no fue clara, lo cual sugiere la utilización de múltiples estrategias en las especies, que permiten asegurar una mayor ganancia de carbono al tiempo que la pérdida de agua no pone en riesgo su sobrevivencia.…”

“…Los mecanismos de disipación requieren de la inversión en pigmentos relacionados con la absorción de fotones, pero de manera significativa en pigmentos que permitan su disi pación no fotoquímica cuan- la mayor concentración de Chl a/b en el sitio con mayor aridez, podría ayudar a evitar el daño por estrés y alta irradiancia (Thayer & Björkman 1990, Zhu et al 2003, más cuando existe menor disponibilidad de N (Maina & Wang 2015), tal como se observó en el sitio más árido (SJ). Aunque la inversión en fotoprotección puede ser costosa para la planta, parece evitar costos mayores a largo plazo ocasionados por fotodaño (Kothari et al 2019, Marozas et al 2019.…”

Transpiration Rate of Scots Pine Trees on Very Oligotrophic Soils of Normal Moisture in Relation to Different Meteorological Condition

“…Its drought sensitivity depends on site related factors especially on relief, topography and soil characteristics such as rooting and water holding capacity of soils (Levesque et al, 2014). Therefore, the reactions of this considered tree species to extreme meteorological events under different growth conditions differed significantly due to their different strategies (McDowell 2008;Augustaitis et al, 2018;Marozas et al, 2019) when surviving first of all heat and drought episodes (Lévesque et al, 2014;Augustaitis 2021) what quite well indicates their needles spectral reflectance (Masaitis et al, 2013(Masaitis et al, , 2014. This finding well agreed with results obtained on annual scale which indicated that meteorology explained variation in annual pine tree ring width variation more significantly than acidifying compounds (Augustaitis et al, 2007b(Augustaitis et al, , 2015(Augustaitis et al, , 2018Juknys et al, 2014).…”

Inconsistent phenotypic differentiation at physiological traits in Norway spruce (Picea abies Karst.) provenances under contrasting water regimes

“…A trait employed to guide the choice of seed sources must be under genetic control (at least partially). Both observational and manipulative experiment demonstrated responsiveness of physiological parameters to environmental stresses (Pollastrini et al 2017;Marozas et al 2019;Hájíčková et al 2021), but the evidence for their genetic basis is often lacking.…”