Leaf physiological and morphological constraints of water-use efficiency in C3_3 plants

The increasing evaporative demand due to climate change will significantly affect the balance of carbon assimilation and water losses of plants worldwide. The development of crop varieties with improved water-use efficiency (WUE) will be critical for adapting agricultural strategies under predicted future climates. This review aims to summarize the most important leaf morpho-physiological constraints of WUE in C3 plants and identify gaps in knowledge. From the carbon gain side of the WUE, the discussed parameters are mesophyll conductance, carboxylation efficiency and respiratory losses. The traits and parameters affecting the waterside of WUE balance discussed in this review are stomatal size and density, stomatal control and residual water losses (cuticular and bark conductance), nocturnal conductance and leaf hydraulic conductance. In addition, we discussed the impact of leaf anatomy and crown architecture on both the carbon gain and water loss components of WUE. There are multiple possible targets for future development in understanding sources of WUE variability in plants. We identified residual water losses and respiratory carbon losses as the greatest knowledge gaps of whole-plant WUE assessments. Moreover, the impact of trichomes, leaf hydraulic conductance and canopy structure on plants’ WUE is still not well understood. The development of a multi-trait approach is urgently needed for a better understanding of WUE dynamics and optimization

Effect of Hydropriming and Osmopriming on the Germination and Seedling Vigor of the East Indian Sandalwood (Santalum album L.)

The natural populations of East Indian sandalwood (Santalum album L.) are very confined and are facing a drastic decline over the past three decades due to overexploitation. Santalum album L. seeds, in general, have poor and staggered germination, which is the major constraint in raising seedlings in nursery and establishing plantations. In the present investigation, we studied the impact of hydro- and osmopriming on the germination attributes and seedling performance of Santalum album L. The Polyethylene glycol (PEG-6000) solutions at four concentrations of 5, 10, 15, and 20% and four durations of 2, 4, 6, and 8 days and hydropriming for the same durations were applied. Results indicated that the osmopriming of seeds at PEG solutions at 5% concentrations for 2 days recorded the highest germination (79%), which is 42% higher than the control group. Longer priming times (6–8 days) had no effect or negatively affected the germination and growth. Moreover, hydropriming had no significant impact on the germination percentage of sandalwood seeds. The positive growth after osmopriming was connected with higher β-amylase content, higher carbohydrate and fat content, and lower electrical conductance of the seeds. Osmopriming can be recommended as a suitable and low-cost technology in enhancing the seed germination and seedling growth of Santalum album L. to produce quality planting material. Further testing of osmoprimed seedlings under abiotic stress conditions may help to explore its possible acclimation potential for stress resistance

Sap flow and growth response of Norway spruce under long-term partial rainfall exclusion at low altitude

Introduction: Under ongoing climate change, more frequent and severe drought periods accompanied by heat waves are expected in the future. Under these conditions, the tree’s survival is conditioned by fast recovery of functions after drought release. Therefore, in the presented study, we evaluated the effect of long-term water reduction in soil on tree water use and growth dynamics of Norway spruce. Methods: The experiment was conducted in two young Norway spruce plots located on suboptimal sites at a low altitude of 440 m a.s.l. In the first plot (PE), 25% of precipitation throughfall was excluded since 2007, and the second one represented the control treatment with ambient conditions (PC). Tree sap flow, stem radial increment, and tree water deficit were monitored in two consecutive growing seasons: 2015-2016, with contrasting hydro-climatic conditions. Results: Trees in both treatments showed relatively isohydric behavior reflected in a strong reduction of sap flow under the exceptional drought of 2015. Nevertheless, trees from PE treatment reduced sap flow faster than PC under decreasing soil water potential, exhibiting faster stomatal response. This led to a significantly lower sap flow of PE, compared to PC in 2015. The maximal sap flow rates were also lower for PE treatment, compared to PC. Both treatments experienced minimal radial growth during the 2015 drought and subsequent recovery of radial growth under the more the humid year of 2016. However, treatments did not differ significantly in stem radial increments within respective years. Discussion: Precipitation exclusion treatment, therefore, led to water loss adjustment, but did not affect growth response to intense drought and growth recovery in the year after drought

Utilization of Slags from Foundry Process

The melting of steel or cast iron is one step of the foundry process. The foundry industry uses different types of furnaces, and metallurgical slags are products of the pyrometallurgical processes defecting in these furnaces. Furnace slag is a non-metallic by-product that consists primarily of silicates, alumina silicates, and calcium-alumina-silicates. As a by-product of the melting process, furnace slags vary considerably in form depending on the melted metal furnace types, and slag cooling method used. Most quantity of slags from the foundry processes are created in a cupola furnace that is used for cast iron production. An electric arc furnace is usually used for steel production, but it can be used for cast iron production as well. Universal use features an electric induction furnace. Slags from the melting processes in a foundry can be in the form of gravel, or the slag from a cupola furnace can be granulated. The utilization of slags from foundry processes is very delimited in Slovakia because of their quantity. This article deals with the possibility of using foundry slag as a binder in civil engineering. A basic property of a binder in civil engineering is its hydraulicity, which can be given by compression strength. Four metallurgical slags were tested. The values of the compressive strength of the slags were low, but addition cement to the slags resulted in a strong increase in the value of the compressive strength

The combined effect of branch position, temperature, and VPD on gas exchange and water-use efficiency of Norway spruce

The impact of climate change on the physiological processes of Norway spruce in Central Europe is a significant concern. The increased temperature and evaporative demand associated with climate change may negatively affect its photosynthesis and carbon-water balance. This study tests the combined effect of branch position, temperature (T) and water vapour pressure deficit (VPD) on net photosynthetic rate (P$_N$), water vapour stomatal conductance (g$_s$), and intrinsic water-use efficiency (WUE$_i$) of Norway spruce. More than 11 000 gas-exchange measurements during the summer of 2018 revealed that branch position significantly affects gas exchange and WUE$_i$ of juvenile Norway spruce trees. Northern branches showed on average 21% increased P$_N$, 35% higher g$_s$, and 8% lower WUE$_i$ compared to the southern branches (across T and VPD conditions). The P$_N$ and g$_s$ differences between the branches were temperature- and VPD-dependent. We observed the negative impact of raising temperature on gas exchange and WUE$_i$ for both treatments, with a 40°C threshold causing a rapid decline in WUE$_i$. Variability of the southern branches\u27 WUE$_i$ at 42°C was abruptly increased due to the decoupling of P$_N$ and g$_s$ (low P$_N$, high g$_s$). Surprisingly, raising VPD showed no significant impact on WUE$_i$ of Norway spruce. The results of this study provide necessary information for upscaling and process-based modelling of whole-crown gas exchange. Moreover, experimental studies of gas exchange should take into consideration the branch position effect to prevent possible bias errors

Impact of Environmental Conditions and Seasonality on Ecosystem Transpiration and Evapotranspiration Partitioning (T/ET Ratio) of Pure European Beech Forest

Partitioning of evapotranspiration (ET) into transpiration (T) and residual evaporation (E) is a challenging but important task in order to assess the dynamics of increasingly scarce water resources in forest ecosystems. The T/ET ratio has been linked to the ecosystem water use efficiency of temperate forests, and thus is an important index for understanding utilization of water resources under global climate change. We used concurrent sap flow and eddy-covariance measurements to quantify the ET partitioning in pure European beech forest during the 2019–2020 period. The sap flow data were upscaled to stand level T and combined with stand level ET to calculate the T/ET ratio. We analysed intra-annual dynamics, the effect of seasonality and the impact of meteorological conditions on T, ET and T/ET. Annual T/ET of a pure European beech ecosystem was 0.48, falling at the lower end of reported global T/ET values for forest ecosystems. T/ET showed significant seasonal differences throughout spring (T/ET = 0.28), summer (T/ET = 0.62) and autumn (T/ET = 0.35). Air temperature (R$^2$ = 0.45–0.63), VPD (R$^2$ = 0.47–0.6) and PAR (R$^2$ = 0.32–0.63) affected the daily dynamics of T, ET and T/ET; however, soil water content (SWC) had no significant effect. Mature European beech trees showed more anisohydric behaviour and relatively stable T/ET, even under decreasing SWC. The results improve the understanding of ecosystem scale T, ET and T/ET intra-annual dynamics and environmental constraints in anisohydric mature European beech

The Role of Provenance for the Projected Growth of Juvenile European Beech under Climate Change

European beech is one of the most common tree species in Europe and is generally suggested to play even more of a prominent role in forestry in the future. It seems to have the potential to partially replace Norway spruce, as it is less sensitive to expected warmer and drier conditions. It is, however, not well known in which regions these new plantings would be particularly favourable and if specific provenances may be better adapted to the new conditions than others. Therefore, we estimated the potential early height growth under climate conditions in 2040–2060 for 20 beech provenances across a region covering the Czech Republic and Slovakia. This Central European region is expected to experience considerably drier and warmer conditions in the future. For this exercise, we implemented a new neural network model developed from height growth information obtained from the open-access BeechCOSTe52 database. The simulations are driven by past and future climate data obtained from the WorldClim database of historical climate data and future climate projections. Simulations revealed that provenances originating from drier regions performed on average significantly better than those from regions with good water supply. Moreover, provenances originating from drier regions had a particularly large advantage in the relatively arid regions of Central Czechia and Southern Slovakia. We can also confirm that all provenances showed a high phenotypic plasticity of height growth across the whole investigated region

Suggestion of an optimal numerical method for solution of the Rayleigh-Plesset equation with rebounding

Na/ev pram: X a v i l i opt.inia.lm niunericke metody pro le.^ loviuce s pmdkyini kavil acni'mi kolapsx Autor: Peter Peln'k Katedra (usl.av): Malemalickv uslav I ' K Vedouci bakalafske prace: Piol. hit!,. Marsik Fianlisek. UrSc. e-mail vodouci'lio: marsik'nt .ras.c/ Abstrnkt: V praci si ndnicme presnost a casovou miioenosl jednokrokovvch ex- plicit niVh I l i r t u d ( Klin;!,c-l\UtT;i. Bulirscll-St oer) s ;id;ipt a h i l l l l l l l klokem v Kayleijdl- Plesselove lovnici, ktera popiMije vyvoj polomei n pi v nne l)iil)iiii\ \ kapalinr sc /nicnaini tln.ku. McUidv pndcriiujf lok/ilni chybii \ nn.stccli kdlapsu hiihlin. av^ik ^lobi'ilnf c!i\'l)a /usta"\;i \ nidu pou/itc tulcrancc, Bulii'scli-St.ocr inctdda \a ncjiiKMis] CMSOVOH nai'ociK)St. V pfi'padr [^ini^c-Kullii iiK'tnd /;i.\isi \ylicr o|itiiiuil)ii nirtdd\ na pou/itr lolcranci. Pli slrcdnicli tnln ancich ur\'i lilujc \-vpocc! i pnuxiti iT^ukiri/acr. (j. xavcdciii niA'f'1 jicx/ixihlr pmiiirnnr nii'slo rasu. ('MSOV-'I ii/irocno^l poti/,it(' i)nMod\c tiicni' s ruxnynii pou/Jtyini vaiiatil a.nii rovtiicc (i/u(cnuick;i aproxi- inacr/adialiat ick/i aproxiniacc plvniic sln/ky olisa.hu luililiiiy. si lacilt'lun./ nest a.rit.clna kapalina)- I'l'i nekteryeh naslavcniYli \st ilpni'eli paranirl I'll \ i/,ol enilirkc vai'iatile io\"iiice doelii'txi k padu \'ypoelu...Na/ev pram: X a v i l i opt.inia.lm niunericke metody pro le.^ loviuce s pmdkyini kavil acni'mi kolapsx Autor: Peter Peln'k Katedra (usl.av): Malemalickv uslav I ' K Vedouci bakalafske prace: Piol. hit!,. Marsik Fianlisek. UrSc. e-mail vodouci'lio: marsik'nt .ras.c/ Abstrnkt: V praci si ndnicme presnost a casovou miioenosl jednokrokovvch ex- plicit niVh I l i r t u d ( Klin;!,c-l\UtT;i. Bulirscll-St oer) s ;id;ipt a h i l l l l l l l klokem v Kayleijdl- Plesselove lovnici, ktera popiMije vyvoj polomei n pi v nne l)iil)iiii\ \ kapalinr sc /nicnaini tln.ku. McUidv pndcriiujf lok/ilni chybii \ nn.stccli kdlapsu hiihlin. av^ik ^lobi'ilnf c!i\'l)a /usta"\;i \ nidu pou/itc tulcrancc, Bulii'scli-St.ocr inctdda \a ncjiiKMis] CMSOVOH nai'ociK)St. V pfi'padr [^ini^c-Kullii iiK'tnd /;i.\isi \ylicr o|itiiiuil)ii nirtdd\ na pou/itr lolcranci. Pli slrcdnicli tnln ancich ur\'i lilujc \-vpocc! i pnuxiti iT^ukiri/acr. (j. xavcdciii niA'f'1 jicx/ixihlr pmiiirnnr nii'slo rasu. ('MSOV-'I ii/irocno^l poti/,it(' i)nMod\c tiicni' s ruxnynii pou/Jtyini vaiiatil a.nii rovtiicc (i/u(cnuick;i aproxi- inacr/adialiat ick/i aproxiniacc plvniic sln/ky olisa.hu luililiiiy. si lacilt'lun./ nest a.rit.clna kapalina)- I'l'i nekteryeh naslavcniYli \st ilpni'eli paranirl I'll \ i/,ol enilirkc vai'iatile io\"iiice doelii'txi k padu \'ypoelu...Matematický ústav UKMathematical Institute of Charles UniversityFaculty of Mathematics and PhysicsMatematicko-fyzikální fakult