Transpiration Flow Research Articles

Effect of vapor pressure deficit on the photosynthesis, growth, and nutrient absorption of tomato seedlings

Vapor pressure deficit (VPD) is the main driving force of plant water transport and affects the nutrient absorption of plants. Exploring the nutrient absorption, growth, and photosynthetic characteristics of different tomato cultivars under different VPDs is of great importance for the cultivation of tomato. This experiment featured two levels of VPD (high 2.2/low 0.9 kPa) and two tomato cultivars (Solanumlycopersicum L., cv. Jinpeng and cv. Zhongza) for a total of four treatments in two controlled environment growth chambers. After about 4 weeks, the seedlings (at the three true-leaf stage) were transplanted into pots flled with inorganic medium and watered with nutrient solution. The stomatal characteristics, leaf moisture status, net photosynthetic rate (An), and plant growth of Jinpeng were not significantly different under the two VPD treatments, but high VPD resulted in a significantly increased transpiration rate (E) and whole plant hydraulic conductance (Kplant), as well as significantly increased absorption of potassium (K) and calcium (Ca) in various organs. In contrast, Zhongza had lower biomass, smaller stem height, and lower total leaf area under high vs. low VPD conditions. At high VPD, the reduction of photosynthesis in Zhongza was mainly caused by anatomical modifications of the stomata; significant reductions in stomatal aperture and length restricted photosynthesis and biomass accumulation. Moreover, the E and Kplant of Zhongza were reduced by stomatal state changes that prevent excessive transpiration. High VPD limited plant transpiration and mass flow of water, which reduced the absorption and accumulation of nutrients. Overall, these results suggest tomato cultivars differ in their stomatal sensitivity. Specifically, increasing VPD resulted in increased levels of some nutrients in certain organs in the cultivar with lower stomatal sensitivity; however, the cultivar with higher stomatal sensitivity demonstrated opposite trends.

Influence of Holes Manufacture Technology on Perforated Plate Aerodynamics.

Transpiration flow is a very important and still open subject in many technical applications. Perforated walls are useful for the purpose of “flow control”, as well as for the cooling of walls and blades (effusive cooling) in gas turbines. We are still not able to include large numbers of holes in the numerical calculations and therefore we need physical models. Problems are related also to the quality of the holes in perforated plates. The present transpiration analysis concerns with experimental investigations of the air flow through perforated plates with microholes of 125 and 300 µm diameters. A good accordance of the results with other experiments, simulations and theory was obtained. The received results very clearly show that technology manufacturing of plate holes influences on their aerodynamic characteristics. It turned out that the quality of the plate microholes using laser technology and, consequently, the shape of the hole, can affect the flow losses. Therefore, this effect was investigated and the flow characteristics in both directions were measured, i.e., for two plate settings.

The importance of tree internal water storage under drought conditions.

Global warming and drying trends, as well as the increase in frequency and intensity of droughts, may have unprecedented impacts on various forest ecosystems. We assessed the role of internal water storage (WS) in drought resistance of mature pine trees in the semi-arid Yatir Forest. Transpiration (T), soil moisture and sap flow (SF) were measured continuously, accompanied by periodical measurements of leaf and branch water potential (Ψleaf) and water content (WC). The data were used to parameterize a tree hydraulics model to examine the impact of WS capacitance on the tree water relations. The results of the continuous measurements showed a 5-h time lag between T and SF in the dry season, which peaked in the early morning and early afternoon, respectively. A good fit between model results and observations was only obtained when the empirically estimated WS capacitance was included in the model. Without WS during the dry season, Ψleaf would drop below a threshold known to cause hydraulic failure and cessation of gas exchange in the studied tree species. Our results indicate that tree WS capacitance is a key drought resistance trait that could enhance tree survival in a drying climate, contributing up to 45% of the total daily transpiration during the dry season.

Interspecific Soil Water Partitioning as a Driver of Increased Productivity in a Diverse Mixed Mediterranean Forest

AbstractIt has been assumed that mixing of species with high physiological diversity reduces competition over water and light resources, compared to single‐species forests. Although several mechanisms to explain this observation have been proposed, quantification of these effects is lacking. Here we studied water‐use dynamics for five tree species in a mature, mixed, evergreen, and Mediterranean forest. We use empirical measurements of key tree structural attributes including root distribution, through DNA barcoding and soil cores, tree height and biomass along with measurements of species‐specific water use for two years. These measurements at the tree‐scale were used to parameterize an ecosystem model of coupled water, carbon and energy fluxes (Regional Hydro Ecologic Simulation System, RHESSys). Site‐scale empirical measurements showed contrasting diurnal and seasonal transpiration and sap flow curves across tree species, with year‐round activity in angiosperms, and mostly wet season‐activity in gymnosperms. Water‐use patterns matched the rooting depth patterns, with the deep‐ and shallow‐rooted Ceratonia and Cupressus, showing year‐round and seasonal behaviors, respectively. RHESSys estimates of species‐specific and stand‐scale transpiration, biomass and productivity across 20 years of climate variation showed substantial differences between mixed and monoculture scenarios. Stand‐scale annual net primary productivity and transpiration increased by 20–70 g C m−1 yr−1 and 40–80 mm yr−1, respectively, for mixed stands relative to average fluxes aggregated across monocultures. Model results, collaborated by field data provide evidence for niche partitioning of the soil water resource among co‐habiting tree species, and demonstrate that this mechanism can facilitate higher productivity and an enhanced forest carbon sink especially in semi‐arid regions.

Xylem, phloem and transpiration flows in developing strawberries

The fruit of many species suffer a loss of xylem functionality during development. This reduces Ca import, so lowers fruit Ca concentration and impairs postharvest performance. Even though not a true fruit, this pattern may also apply to strawberry. Our aim was to measure xylem and phloem inflows to a developing strawberry and transpiration outflows. To do this, we used linear variable displacement transducers mounted on still-attached fruit and potometers on detached fruit. In attached fruit, the stalk inflows were partitioned into xylem and phloem components by killing the phloem with steam.Fruit mass increased sigmoidally till the fully-mature. The balance between xylem, phloem and transpiration flows followed a characteristic pattern of change during development. Early on, xylem inflow was 70–80% of total water inflow, towards maturity this decreased to ~36%. In contrast, phloem inflow increased from 20 to 30% of total early on, rising to ~64% at maturity.Aqueous acid fuchsin was used as a marker of xylem sap flow. When fed through the cut surface of the stalk of a detached fruit, staining of the fruit vascular system was uniform in young fruit, but progressively less uniform as the fruit developed. By full maturity no dye penetrated beyond the base of the fruit.Potometric flow rates into the fruit increased from 8 to 27 days after full bloom, then decreased until maturity. The inflow rate of a fruit held at ~0% RH always exceeded that in one held at ~100% RH. Removing the calyx decreased the inflow rate. The calyx accounted for ~50% of total fruit transpiration (i.e. of fruit + calyx).As indexed both by dye penetration and by xylem flow measurements, xylem functionality decreased during fruit development.

Xylem, phloem and transpiration flows in developing European plums.

Neck shrivel is a quality disorder of European plum (Prunus × domestica L.). It has been suggested that backflow in the xylem (from fruit to tree) could contribute to the incidence of neck shrivel in plum. The objective was to quantify rates of xylem, phloem and of transpiration flow in developing plum fruit. Using linear variable displacement transducers, changes in fruit volume were recorded 1) in un-treated control fruit, 2) in fruit that had their pedicels steam-girdled (phloem interrupted, xylem still functional) and 3) in detached fruit, left in the canopy (xylem and phloem interrupted). Xylem flow rates were occasionally negative in the early hours after sunrise, indicating xylem sap backflow from fruit to tree. Later in the day, xylem flows were positive and generally higher in daytime and lower at night. Significant phloem flow occurred in daytime, but ceased after sunset. During stage II (but not during stage III), the rates of xylem flow and transpiration were variable and closely related to atmospheric vapor pressure deficit. The relative contribution of xylem inflow to total sap inflow averaged 79% during stage II, decreasing to 25% during stage III. In contrast, phloem sap inflow averaged 21% of total sap inflow during stage II, increasing to 75% in stage III. Our results indicate that xylem backflow occurs early in the day. However, xylem backflow rates are considered too low to significantly contribute to the incidence of neck shrivel.

Field evidence reveals conservative water use of poplar saplings under high aerosol conditions

Abstract Anthropogenic aerosols could alter multiple meteorological processes such as radiation regime and air temperature, thereby modifying plant transpiration. However, the lack of field observations at leaf and plant level hinders our ability to understand how aerosols could affect plant water use. Aerosol concentrations in northern China fluctuate periodically over a wide range. Taking advantage of this unique natural experiment opportunity, we conducted a series of physiological and environmental measurements at different times of the day to explore diurnal aerosols' effect on leaf transpiration and sap flow of planted poplar saplings (Populus × canadensis Moench). We found that high aerosol concentrations suppressed sun leaf transpiration by reducing leaf‐to‐air vapour pressure deficit (VPDleaf), while had no effect on shade leaf transpiration mainly because the negative effect of reduced VPDleaf on transpiration offset the positive effects of the increased stomatal conductance (gs). As aerosol concentration increased, the gs of both sun and shade leaves decreased more rapidly with an increase in VPDleaf, which caused their transpiration rates to become less sensitive to VPDleaf. Similarly, aerosols reduced sap flow density and its sensitivity to VPD. Synthesis. Our study provided observational evidence on aerosols' effects on plant transpiration at the leaf and canopy scales. The reduced transpiration and stronger stomatal control indicated that plant water use becomes more conservative under elevated aerosol concentrations.

Photosynthetic apparatus efficiency, phenolic acid profiling and pattern of chosen phytohormones in pseudometallophyte Alyssum montanum

The present study investigated the response of non-metallicolous (NM) and metallicolous (M) Alyssum montanum shoots cultured in vitro on a medium supplemented simultaneously with heavy metals (HMs) to identify mechanisms involved in alleviating metal-induced damage. Plant status in respect to photosynthetic apparatus efficiency was determined and linked with changes in biochemical composition of shoots, namely phenolic acids’ and stress-related phytohormones. Results showed the considerable inter-ecotype differences in (1) the photosynthetic pigments’ amount, (2) the functioning of membrane electron transporters as well as (3) the linear and alternative electron transport pathways, whose lower values were reported in NM than in M HM-treated culture. Photosynthetic apparatus protection in M specimens was assured by the activation of cinnamic acid synthesis (by phenylalanine ammonia lyase) and its further transformations to benzoic acid derivatives with high ability to counteract oxidative stress, that was accompanied by the overexpression of jasmonic acid stimulating antioxidant machinery. In turn, detrimental HM effects on NM shoots could result from the diminution of most phenolics’ accumulation, and only the content of coumarate (produced by bifunctional phenylalanine/tyrosine ammonia lyase) and rosmarinic acid increased. All these together with an enhanced concentration of abscisic acid might suggest that NM strategy to cope with HMs is based mostly on a restriction of metal movement with transpiration flow and their limited distribution in leaves. Summarizing, our findings for the first time point out the physiological and metabolic adaptation of pseudometallophyte A. montanum to adverse conditions.

Grapevine berry shrivelling, water loss and cell death: an increasing challenge for growers in the context of climate change

Late ripening berry dehydration is an important phenomenon that occurs through grape berry water loss due to the alteration of the fruit water budget when transpiration and potential water back flow to the plant exceed the import of water into the berry through the phloem and xylem. Berry shrivelling can have a significant economic impact, reducing yields by ≥25 % with consequences on berry composition and the resulting wine. Its occurrence and consequences are expected to increase due to predicted climate change, shifting grape development and ripening into warmer periods (i.e., heat waves and drought events).

The efficiency of transpiration flow through perforated plate

The interest in transpiration flows through perforated walls is recently increasing again because the manufacturing of such walls is much easier than in former decades. Recently the interest is related to laminar wing technology and effusive cooling in aeroengines. Transpiration flows become useful also for other applications as reduction of separation and other flow control devices as passive shock wave boundary layer control.Plates perforation used for the mentioned above flow control application is rather low at the level below 10%. In order to minimize the flow disturbance small hole diameters are used, well below 1 mm. This means that there is a large number of holes, which cannot be directly included in the numerical simulations. Therefore physical model is still necessary to serve as boundary condition at perforated wall. Several models have been offered formerly with limited success.In the present paper a new model is proposed, which is able to incorporate whole pressure drop range from weak pressure differences to chocking conditions. To create and verify the model experimental investigations as well numerical simulations were taken into account. As the quality of holes has important impact on the plate aerodynamic performance, the model introduces plate effectiveness coefficient. This coefficient allows to take into account perforation quality.

Effects of highly concentrated KCl foliar spray for managing the occurrence of the internal brown spot, a physiological disorder of potato tubers

ABSTRACT Potato (Solanum tuberosum L.) under Mediterranean climate may be affected by internal brown spot, non-pathogenic disorder of flesh tissues leading to a dramatic depreciation of tubers. Its aetiology is still clarifying; however, some abiotic stressors, such as the high temperatures, heat and drought are noticed as crucial factors exacerbating the physiological decline. With the aim of escaping the potato growth stages most prone to the physiopathy, shortening cropping cycle by KCl-induced potato canopy desiccation was experimented on two field trials. Experimental field treatments were two consecutive KCl foliar applications, respectively at thirty and twenty days before harvesting, at 113 and 75 g L−1, that were compared to the water-sprayed control. Salt solution spraying injured above-ground parts ending potato’s growth early reducing incidence of tuber internal browning, on average, between 30% and 50% at low and high KCl concentration, respectively. The non-sensitive cultivar Agria proved the most productive, whereas Ricciona di Napoli resulted strongly defected by the physiopathy. Under low-irrigation regime, IBS occurrence was reduced of about 39%. The reduction of the transpiration flow and growth cycle likely decreased internal brown spot under KCl vine desiccation, as well as the role of KCl on tuber ripening dynamics cannot be overlooked.

Lead uptake and translocation pathways in soybean seedlings: the role of ion competition and transpiration rates.

Glycine max (L.) Merr. (soybean) crop plants have been found to have high lead (Pb) levels in aerial organs; however, knowledge about the processes involved in the incorporation, and subsequent translocation and accumulation of the metal in the plants is scarce. Considering the toxicity of this heavy metal, the aim of the present study was to evaluate Pb uptake and translocation, and their toxic effects on soybean seedlings via experiments of ionic competition with Ca2+ (2.5 mM, Ca:Pb 1:1) and alteration of the transpiration flow [0.25 mM Pb(NO3)2]. The following variables were analyzed: biomass, leaf area (morphological parameters), photosynthetic efficiency, biochemical response (considered physiological stress markers: antioxidant power, chlorophylls, carotenoids, starch, proteins, sugars, and malondialdehyde), and Pb content. Results showed that soybean seedlings can accumulate high Pb concentration in its organs; however, in general, no morpho-physiological Pb stress symptoms were observed, except for lipid peroxidation and antioxidant power. The treatment with Ca ions was not effective in reducing Pb entry into root over time when both Ca and Pb where present in the grow solution. Alteration of the transpiration rate in soybean showed that the air flow increased the consumption of solutions, regardless of the treatments. However, Pb accumulation was lower in seedlings exposed to air flow, indicating a selective exclusion of the metal in the solution. In both experiments, soybean seedlings showed to be tolerant to high Pb concentrations.

Molecular dynamics study on flow structure inside a thermal transpiration flow field

Thermal transpiration flow is a thermally driven flow from a cold part toward a hot part using a temperature gradient along a wall under a high Knudsen number condition. Many studies have used this type of flow as a pump for microtechnology. The flows adopted in these studies were, in most cases, in the slip or transitional regime. Accordingly, in this research, thermal transpiration flow through a two-dimensional channel with nanoscale clearance in the height direction was studied using the molecular dynamics method. The solid atoms composing the channel walls were explicitly considered. The center part of the nanochannel was controlled as a hot reservoir, whereas both ends of the nanochannel were kept cold. The temperatures of the channel wall atoms were also controlled based on their positions by linearly interpolating the temperature between the hot and cold reservoirs. Two Knudsen number conditions were adopted by changing the width of the computational cell. To study the mean velocity distribution inside the nanochannel, these simulations were performed for 10 ns. We successfully obtained a mean velocity distribution inside the nanochannel, showing the thermal transpiration flow in the vicinity of the channel wall using the pressure-driven counterflow at the center in the height direction even under the dense gas condition. The velocity profile across the nanochannel in the height direction indicated that thermal transpiration flow was induced in the adsorption layer of gas molecules on the channel wall under the dense gas condition.

Shallow urban aquifers under hyper-recharge equatorial conditions and strong anthropogenic constrains. Implications in terms of groundwater resources potential and integrated water resources management strategies

Humid equatorial regions are recognized as the least documented in term of hydrogeological functioning of aquifers despite the fact that they house a lot of developing countries and that groundwater is often the main water resource. Regarding this aspect, a study was conducted in sub-Saharan Africa, focusing on the Mio-Pliocene aquifer in Douala megacity (Cameroon) which is the rainiest city in West-Africa (about 4000 mm/year) with one of the greatest demographic growth rate of the African continent. Firstly, groundwater recharge rate has been calculated through water balance and Water Table Fluctuation methods. Results show that the aquifer is characterized by a high recharge of 600–760 mm/year. Then infiltration process and groundwater flow conditions have been examined by combining hydrogeological and isotopic methods. Rainwater infiltrated is recycled in the vadose zone through plants roots transpiration and groundwater flows with a Darcy velocity of 5 m/day. From the recharge area to the estuary, the mineralization increases controlled by anthropogenic activities and water-rocks interactions which are amplified by the residence time and accelerated by the hot and humid climate of Douala. The paper ends with the determination of natural background levels (NBLs) and threshold values (TV) of chemical components in groundwater to assess the contamination for different flow paths. This multi-proxy study and the establishment of NBLs and TV can be beneficial to improve groundwater resources management. Moreover, the conceptual model provided in this study could be used as a reference for porous aquifers submitted to high rainfall amount.

Demonstration of Atmospheric-Pressure Radiometer With Nanocardboard Vanes

Crookes radiometers have been the subject of numerous theoretical, numerical, and experimental studies because of the complicated forces they exhibit as well as their potential applications to light sensing and actuation. The majority of these studies have focused on classical radiometers, which function under low vacuum pressures. In contrast, here we report a radiometer with microengineered vanes that rotates at atmospheric pressure. Its functionality at pressures thousands of times higher than previous light mills is due to unique attributes of the nanocardboard that forms its vanes: 1) the extremely low areal density (0.1 mg/cm2) of nanocardboard reduces the vane masses by two orders of magnitude; 2) its lower thermal conductivity allows a greater cross-vane temperature difference; and 3) its microchannels dramatically increase the thermal transpiration flow that drives the rotation. Intriguingly, the experimentally observed rotation speeds are substantially higher than those theoretically expected. Our device demonstrates new possibilities for micromanipulation, propulsion of aerial vehicles, and light-powered generators. [2020-0165]

Highly dilute gas flows through a non-isothermal planar microchannel

This paper reports theoretical and numerical investigations on free molecular gas flows through microchannels. Both diffusely and specularly reflective channel surfaces are considered. Gas kinetic methods are adopted to develop the analytical solutions for surface and flowfield properties. The crucial steps include constructing the velocity distribution functions (VDFs) for points at the plate surfaces and inside flowfield and then completing the integration over the related velocity phases. For diffusely reflective surfaces, the VDFs are related to the densities and temperatures at the two exits and the plate, respectively. For surfaces with specular reflections, the VDFs at the plate surface and inside the flowfield are identical and are independent of the surface temperature ratio and the geometric aspect ratio. Based on the VDFs and velocity phases, surface property coefficients (e.g., Cp, Cf, and Cq) and flowfield properties (e.g., density, velocity components, and temperature) are obtained. For the diffusely reflective surface scenario, the mass flow rate can be approximated and the results include four non-dimensional parameters: the aspect ratio, the density ratio, and two temperature ratios. For the specularly reflective surface scenario, the surface and flowfield properties are uniform everywhere, and the channel aspect ratio and plate temperatures do not have any influence. Particle simulations with the direct simulation Monte Carlo method are performed, and essentially identical results validate the theoretical work. This work is heuristic and can be used to investigate less rarefied microchannel gaseous flows, for example, aid experimental measurement design for thermal transpiration flows.

Physiological response of two olive cultivars to secondary metabolites of Verticillium dahliae Kleb.

The effects of two purified fractions (formerly D-SXM and ND-SXM) produced in vitro by defoliating (Vd312D) and non-defoliating (Vd315ND) strains of Verticillium dahliae were studied on twigs of Olea europaea cvs Frantoio and Leccino. Symptoms, such as leaf curling, yellowing, vein clearing and defoliation, which are observed on the two cultivars naturally affected by Verticillium wilt, were produced by these fractions. Physiological changes were induced during the first seven days after the absorption of solutions containing ND-SXM or D-SXM. Both fractions increased the transpiration flow from abaxial leaf surfaces. Cell membrane and antioxidant activity were the most important action sites of ND-SXM and D-SXM. ND-SXM influenced malondialdehyde concentration in ‘Leccino’ leaves, while D-SXM increased the percentage of electrolyte leakage in ‘Frantoio’. Both fractions reduced the total non-enzymatic antioxidant activity on the leaves of the treated twigs. The total phenol content increased in both cultivars, without differences to the control. Variations on electrolyte leakage and total antioxidant activity were effective in discriminating the two tested olive cultivars for V. dahliae tolerance or susceptibility. If V. dahliae strains Vd315ND and Vd312D produce ND-SXM and D-SXM in the infected plants, these metabolites may move via the xylem sap, accumulate in the leaves and induce changes that will lead symptoms on the leaf by compromising the cell membranes physiology.

Spatially Resolved Localization of Lanthanum and Cerium in the Rare Earth Element Hyperaccumulator Fern Dicranopteris linearis from China.

The fern Dicranopteris linearis (Gleicheniaceae) from China is a hyperaccumulator of rare earth element (REE), but little is known about the ecophysiology of REE in this species. This study aimed to clarify tissue-level and organ-level distribution of REEs via synchrotron-based X-ray fluorescence microscopy (XFM). The results show that REEs (La + Ce) are mainly colocalized with Mn in the pinnae and pinnules, with the highest concentrations in necrotic lesions and lower concentrations in veins. In the cross sections of the pinnules, midveins, rachis, and stolons, La + Ce and Mn are enriched in the epidermis, vascular bundles, and pericycle (midvein). In these tissues, Mn is localized mainly in the cortex and mesophyll. We hypothesize that the movement of REEs in the transpiration flow in the veins is initially restricted in the veins by the pericycle between vascular bundle and cortex, while excess REEs are transported by evaporation and cocompartmentalized with Mn in the necrotic lesions and epidermis in an immobile form, possibly a Si-coprecipitate. The results presented here provide insights on how D. linearis regulates high concentrations of REEs in vivo, and this knowledge is useful for developing phytotechnological applications (such as REE agromining) using this fern in REE-contaminated sites in China.

Scaling Up Sap Flow Measurements from the Stem Scale to the Individual Scale for Multibranched Caragana Korshinskii on the Chinese Loess Plateau

The traditional heat balance method for measuring plant sap flow (SF) becomes troublesome and uneconomic for multibranched shrub species if all their stems are used for the measurement. The objectives of this study were to explore specific relationships between stem-scale SF and plant morphological traits and then to scale up SF measurements from the stem scale to the individual scale for Caragana korshinskii Kom., a dominant shrub species on the Chinese Loess Plateau. Sap flow was measured for twenty-one stems from three representative individuals from July to September 2018 during the rainy season. The results indicated that the stem-scale SF in C. korshinskii presented a positive linear correlation with the stem base diameter (SBD), stem length (SL), primary branch numbers in the stem (PBN), and estimated stem biomass (W). The SBD-based statistical models performed well in estimating the stem-scale SF, with an R2 value of 0.9726 and root mean squared error (RMSE) of 2.5389 g h−1. Over the canopy projection area, the individual-scale transpiration flows for the three selected C. korshinskii were 1.91, 1.10, and 1.59 mm·d−1. In addition, stem-scale SF was positively and linearly correlated with air temperature, photosynthetically active radiation, vapor pressure deficit, reference crop evapotranspiration, and variable transpiration. This study sheds light on morphological and meteorological influences on stem-scale SF and has made contributes to the accurate and rapid estimation of the plant sap flow from easily available morphological traits for multibranched shrub species in semiarid regions. Limitations, however, may exist for the established model when it is used to estimate SF of C. korshinskii during the water-limited dry season. Our study deserves further exploration of a more general model to have a better estimation of SF for C. korshinskii in both dry and rainy seasons.

Some physiological parameters of the resistance of woody plants in the arid conditions of the Mangystau desert

The purpose of this study was to identify the possibility of using physiological parameters of growth and development of woody plants as markers of their tolerance to the arid conditions of the Mangistau desert zone. Using the generally accepted representative methods for 21 species of trees and shrubs, we studied the seasonal dynamics of the intensity of transpiration and water content of leaves, chlorophyll concentration and heat resistance. According to the magnitude of transpiration consumption of moisture, three groups of introducents were identified: weakly transpiring (<250 mg/g of raw leaves per hour), mediumtranspiring (250-500) and highly transpiring (> 500). A close correlation was established between the intensity of transpiration (IT) and the water content of the leaves of woody plants (r = 0.79). Soil moisture predetermines from 11.6 to 43.6 % of changes in transpiration flow (r = 0.34-0.66). The close connection between the transpiration intensity and relative humidity (r = -0.59) and air temperature (r = 0.46) is credible at 5 % significance level. With the amount of illumination it is associated statistically incredible (r = 0.19). Seasonal dynamics of IT in most introductions looks like a one-peak curve with a maximum in June. For the daytime course of transpiration changes, three types of rhythms are distinguished: “increasing” (from morning to evening), “falling” (from morning to evening) and “variable” (with a maximum at noon). The intensity of the transpiration process due to significant variability and multifactorial nature cannot be counted among the criteria for resistance of woody plants. However, at the same time, a significant correlation was revealed between the biological resistance of introducents and the coefficient of variation of IT. With an increase in its values, the tolerance of plants to arid habitat conditions usually increases due to their increased ability to self-regulate water exchange. Chlorophyll content is characterized by a double-vertex curve with a maximum in June and September. In the most biologically resistant species (elm elm, spinefly), its concentration is less susceptible to seasonal fluctuations. According to the collected research materials, the chlorophyll content cannot yet be considered a credible parameter of plant resistance, since it strongly depends on the bioecological properties of introduced species, especially in adverse conditions of the Mangistau desert. By heat resistance, plants are ranked in three groups: “low” (50 °С) – 3 species; “medium” (60 °С) – 8 and “high” (70 °С) – 3 taxon. As a genetically fixed bioecological parameter, weakly subject to intraspecific changes, it may well be used as a diagnostic characteristic of the introduction value of plants in arid conditions.