High Relative Air Humidity Research Articles

Production of stable amorphous form by means of spray drying

ABSTRACTSpray drying is a very useful method for manufacturing of amorphous solid materials. This is mainly due to the possibility of fast solvent evaporation that leads to a rapid transformation of solution to a solid state. Besides evaporation kinetics, there are various process parameters that influence physical and chemical characteristics of such obtained material. The possibility of obtaining a stable amorphous structure of the active pharmaceutical ingredient in a spray dryer was examined. A solution of the hydrochloride crystalline structure of the active pharmaceutical ingredient in a mixture of water and acetonitrile was dried at different temperatures and flowrates of nitrogen used for atomization, as well as the flowrates of the solution. The influence of the process conditions on the properties of the product was analyzed. The final dried products were characterized and identified with a variety of analytical and physical methods. The results showed that a stable amorphous structure of the high purity active pharmaceutical ingredient is obtained, and that the optimal conditions of the process are defined. The amorphous structure is stable at temperatures below 200°C when it is transformed into a new crystal structure. Conditions of high relative air humidity lead to partial transformation.

The Effect of Storage Condition and Duration on the Deterioration of Primed Rice Seeds.

Seed priming is a successful practice to improve crop establishment under adverse environment. However, reduced longevity of primed rice (Oryza sativa L.) seeds during storage limited the adoption of this technique. Present study investigated the effect of temperature, relative air humidity (RH) and oxygen on the longevity of primed rice seeds in a range of 60 days storage. In addition, the biochemical and morphological mechanisms associated with deterioration of primed seeds during storage were explored. Three types of priming treated rice seeds and one non-primed control were stored under (1) low temperature-vacuum (LT-V), (2) room temperature-vacuum (RT-V), (3) room temperature-aerobic-low RH (RT-A-LH) and (4) room temperature-aerobic- high RH (RT-A-HH) for 0, 15, 30, 45, and 60 days. The results showed that storage of seeds under different conditions for 15–60 days did not influence the longevity of non-primed rice seeds. Meanwhile, the viability of primed rice seeds did not reduce when stored under LT-V, RT-V, and RT-A-LH, but was significantly reduced under RT-A-HH. Under vacuum condition, the increases of storage temperature (30°C) did not reduce the longevity of primed seeds. Likewise, the oxygen did not influence the longevity of primed rice seeds stored under low RH. Nevertheless, increase of RH significantly reduced the viability of primed seeds stored for 15–60 days. Reduced starch metabolism, the consumption of starch reserves in rice endosperms, the accumulation of malondialdehyde and the decreases of antioxidant enzyme activities might be associated with the deterioration of primed rice seeds during storage. In conclusion, storage of primed seeds under high RH condition beyond 15 days is deteriorative for germination and growth of rice. The primed rice seeds are recommended to store at vacuum or low RH or low temperature condition to ensure good crop establishment.

Diversity and main properties of soils of the Gronfjord area (Svalbard archipelago)

Svalbard archipelago is characterized by specific climate conditions, high air temperature and relative air humidity, which are not typical for high latitudes. Such conditions affect soil-forming processes. Classification and morphological structure of the soil cover on the Spitsbergen archipelago are still poorly understood. The aim of current research was to reveal diverse soil taxons in the Gronfjord area and characterize framework of its formation. As the results of this work, the authors provide the description of the investigated soils and their taxonomy in accordance with World Reference Base for Soil Resources (IUSS Working Group 2015) and the new Russian soil classification system. Chemical parameters of the soil, as well and the data on soil horizons properties were measured using vertical electric resistivity sounding method. In total, 15 soil profiles were made and the studied soils were referred to six Soil Reference Groups with domination of Leptosols and Regosols. The profiles were made in different landscapes that allowed to determine the similarities and differences in soil cover of the area. The main factors affected soil formation are cryogenic processes combined with gleyfication and cambic alteration of soil material.

Performance Evaluation of a Desiccant Dehumidifier with a Heat Recovery Unit

In order to effectively increase the drying rate and reduce the energy consumption, a dryer which reduces the air humidity at the dryer inlet using desiccant and regenerates the desiccant by recovering waste heat using a heat pipe heat exchanger was developed in this study. Both the adsorption rate and desorption rate of the dryer were measured at several ambient temperatures ranging from 15 °C to 35 °C, relative humidity levels of air ranging from 20% to 85%, and airflow rates ranging from 30 m3/h to 150 m3/h. The results showed that the adsorption rate in an environment of high relative humidity of air was 4.89 times higher than that of low relative humidity of air at 15 °C. Moreover, the difference in adsorption rate between two given relative humidity of air increased as the ambient temperature decreased. The specific energy consumption estimated with both energy consumption during desorption and the desorption rate indicated that the energy consumption was 8.27 kJ/g H2O without using recovered heat, while the energy consumption was 4.77 kJ/g H2O using recovered heat at 130 °C.

Identification, incidence and control of bacterial blotch disease in mushroom crops by management of environmental conditions

Abstract Bacterial brown blotch disease is one of the most serious bacterial diseases in cultivated mushrooms. Fluorescent pseudomonas isolated from different lesions on the caps of cultivated Agaricusbisporus were identified as strains of Pseudomonas tolaasii and the poorly described Pseudomonas “reactans”. Anaccurate identification of P. tolaasii was carried out by sequencing 16SrDNA gene. Phenotypically the isolates were heterogeneous, which further hindered their correct identification. Regarding P. “reactans”, this bacterial name is not regarded as a valid name and there is no type strain. In this work we have named as P. reactans type those isolates that induce the precipitation of tolaasin. This would suggest that we are not dealing with one species but a group of bacteria. Both, P. tolaasii and P. reactans were shown to be pathogenic in the assays performed, so the aetiology of the disease can be manifold.The incidence of blotch disease in Spanish mushroom crops was evaluated to affect up 15% of the total yield, with the highest losses detected for the second flush. The development of the disease wasassociated with high relative air humidity registered on the irrigation day closest to the harvesting of the second flush, which may lead to condensation on the caps as soon as the air temperature changesif there is no adequate ventilation. Modifying the environmental conditions by increasing the temperature prior to irrigation and moderating the manoeuvres of the drying processhelped control bacterial blotch disease.

Modelled performance of energy saving air treatment devices to mitigate heat stress for confined livestock buildings in Central Europe

Intensive pig and poultry production are predominantly performed in confined livestock buildings which are equipped with mechanical ventilation systems. The frequency of heat stress will increase due to climate change. Heat stress events are accompanied by performance depressions (e.g. daily weight gain, egg production, mortality, feed conversion rate). Consequently, appropriate air treatment devices can become necessary to optimise the indoor climate of confined livestock buildings because of a high inlet air temperature. In this study, we analysed the effects of three energy saving air treatment devices: (1) earth-air heat exchanger, (2) direct evaporative cooling by cooling pads, and (3) indirect evaporative cooling systems which combine evaporative cooling (e.g. by cooling pads) with a subsequent heat recovery system. All systems are compared to a reference ventilation system without air treatment, which is today's typical housing system. The results show that the earth-air heat exchanger (1) is the most efficient air treatment device. It eliminates heat stress and can also be used during wintertime to increase the inlet air temperature. The two adiabatic cooling systems (2) and (3) can reduce heat stress by about 90%. Cooling pads can lead to a high relative humidity of the inlet air between 75% and 100%, which can cause problems inside the livestock buildings, e.g. increasing the moisture content of the bedding material. The indirect cooling device can avoid this disadvantage at the expense of a reduced temperature reduction of the inlet air temperature and higher investment costs.

Dry-season deficit irrigation increases agricultural water use efficiency at the expense of yield and agronomic nutrient use efficiency of Sacha Inchi plants in a tropical humid monsoon area

Application of deficit irrigation (DI) will be problematic in tropical humid monsoon areas, since high relative air humidity during growth there leads to stomata malfunctioning. A field split-plot experiment was used to evaluate the physiological features, growth and seed and oil yield of Sacha Inchi (Plukenetia volubilis Linneo) plants, a tropical promising woody oilseed crop, responded to DI and fertilization in southwest China. The field experiment consisted of a factorial combination of five irrigation levels applied in the dry season [rainfed; DI20, DI50, DI100 (i.e., with irrigation amount of 20, 50 and 100% crop evapotranspiration, respectively); and full irrigation (irrigation of water saturated soil)] combined with two levels of compound fertilizer (0 and 200kgha−1) over two growing seasons, in a randomized complete block design with three replicates.Results showed the growth and root to stem mass ratio had lower sensitivity responded to DI, probably owing to their extremely low root mass fraction and seasonal short-term effect of DI on leaf photosynthetic traits. Irrigation affected the seasonal variations in seed size, seed oil concentration and seed yield, depending on the harvest date; whereas, with constant mean seed size and mean seed oil concentration across irrigation and fertilization treatments, the total seed and seed oil yield over the growing seasons were largely determined by the seed numbers per unit area. The soluble sugar and nitrogen storages as the active process, are related to effective flower formation, fruit (seed) development and enhance productivity of Sacha Inchi plants, which was indicated by the positive relationships between total seed yield and total nitrogen pool in the vegetative tissues or sugar pool in stems across all treatments. Fertilization increased total seed and seed oil yield, but no interaction between irrigation and fertilization was found. Compared with DI100, DI50 and DI20 had significant lower total seed yield, especially under the fertilized condition, although having higher agronomic water use efficiency (WUEagr, yield divided by irrigated water applied) but lower agronomic nutrient use efficiency (NUEagr, increased yield divided by fertilization rate). As a water-demanding crop species, Sacha Inchi plants under DI100 with the similar values to full irrigation had the highest total seed yield and NUEagr, but at the expense of water use efficiency. The maximum seed yield and maximum WUEagr, or maximum WUEagr and maximum NUEagr of Sacha Inchi plants are not compatible because the negative relationships existed between each of them. The polynomial regression relationships between total seed or seed oil yield and relative evapotranspiration could help to develop appropriate water-saving techniques for Sacha Inchi plantation in the tropical humid monsoon region.

Differential effects of elevated air humidity on stomatal closing ability of Kalanchoë blossfeldiana between the C3 and CAM states

High relative air humidity (RH≥85%) impairs stomatal functionality, attenuating plant capacity to cope with abiotic stress. Previous studies were limited to C3 species, so the RH effect on stomatal physiology of CAM plants remains unexplored. We addressed the topic through comparisons of C3 and CAM states in a facultative CAM species. These states were validated by diel measurements of net assimilation rate and malate level. In the first two experiments, three Kalanchoë interspecific hybrid cultivars were exposed to moderate (60%) or high (90%) RH. Both leaves that expanded at high RH and leaves that had expanded at moderate RH and were subsequently exposed to high RH (for nine days) showed increased stomatal conductance. In the third experiment, both C3 and CAM state plants of one K. blossfeldiana cultivar were exposed to low (40%), moderate (60%) or high (90%) RH. Plant transpiration during night-time was inversely related to ambient RH in either state, whereas during day-time a significant effect was only noted at 90% RH. Kalanchoë leaves showed a very effective control of water loss upon water deprivation, especially in the CAM state. Following a single week exposure to 90% RH, detached leaves showed increased rates of water loss during desiccation in C3 state plants. No effect of high RH on stomatal response to desiccation was noted in leaves detached from plants in CAM-state. It is concluded that the negative effect of either growth or one-week exposure to high RH is restricted to the C3 state in Kalanchoë.

Effects of strong earthquakes in variations of electrical and meteorological parameters of the near-surface atmosphere in Kamchatka region

The diurnal variations in electrical (quasistatic electric field and electrical conductivity) and meteorological (temperature, pressure, relative humidity of the atmosphere, and wind speed) parameters, measured simultaneously before strong earthquakes in Kamchatka region (November 15, 2006, М = 8.3; January 13, 2007, М = 8.1; January 30, 2016, М = 7.2), are studied for the first time in detail. It is found that a successively anomalous increase in temperature, despite the negative regular trend in these winter months, was observed in the period of six–seven days before the occurrences of earthquakes. An anomalous temperature increase led to the formation of “winter thunderstorm” conditions in the near-surface atmosphere of Kamchatka region, which was manifested in the appearance of an anomalous, type 2 electrical signal, the amplification of and intensive variations in electrical conductivity, heavy precipitation (snow showers), high relative humidity of air, storm winds, and pressure changes. With the weak flow of natural heat radiation in this season, the observed dynamics of electric and meteorological processes can likely be explained by the appearance of an additional heat source of seismic nature.

Effect of Handling, Packing and Transportation on the Moisture of Timber Wood

In order to improve the efficiency of moisture meters calibrations, we studied the effect of ambient humidity, sample handling, packing and transportation on the timber wood (spruce) moisture determination. It was proved by experiments that dry timber samples ( $$12 \times 12 \times 2.5$$ cm) reach equilibrium within 30–40 days even when moisturizing them at a high relative air humidity (80 %). On the other hand, the major mass loss of moist samples placed at normal laboratory conditions was found to occur during the first few days while the first 5 days are critical. The effects of sample handling, packing and transportation were studied by means of interlaboratory comparison between CMI, CETIAT, INRIM, NIS and KRISS. The obtained results show that samples with moisture content less than 7 % tend to absorb small amount of water, whereas samples with moisture content larger than 15 % tend to desorb small amount of water during the handling and transporting even when using vacuum packing and short handling times.

Moderate salinity improves stomatal functioning in rose plants grown at high relative air humidity

Plants grown at high relative air humidity (RH≥85%) show hampered stomatal closure in response to closing stimuli. We hypothesized that a moderate salinity during growth could trigger a stress response and stimulate stomatal functioning due to an increased leaf abscisic acid concentration ([ABA]). Cut rose ‘Prophyta’ was grown at moderate (63%) or high (89%) RH combined with three electrical conductivities (EC) in the nutrient solution (2, 4 and 6dSm−1; adding NaCl). High RH resulted in higher pore area per leaf area in intact leaves, and higher stomatal conductance (gs) both in leaves subjected to desiccation and to light/dark transition, as compared to moderate RH. Increasing EC in high RH-grown plants lead to higher stomatal density but it enhanced stomatal closure in response to leaflet desiccation. This enhanced stomatal functioning was associated with increased [ABA] and [ABA+metabolites]. Nonetheless, plants grown at EC6 showed a significantly lower chlorophyll content, total plant dry weight and total leaf area. This negative effect on plant growth is related to ionic stress as the sodium and chloride concentrations increased in plants grown at EC6 compared to EC2 (up to 111- and 14-fold, respectively). This is the first study on the interactive effects of RH and salinity on stomatal functioning and anatomy during leaf development. It is shown that, when these two environmental factors that influence stomatal responsiveness in an opposite way are combined, moderate EC is able to improve stomatal responsiveness to leaflet desiccation in high RH-grown plants due to increased leaf [ABA].

Ethylene sensitivity and relative air humidity regulate root hydraulic properties in tomato plants.

The effect of ethylene and its precursor ACC on root hydraulic properties, including aquaporin expression and abundance, is modulated by relative air humidity and plant sensitivity to ethylene. Relative air humidity (RH) is a main factor contributing to water balance in plants. Ethylene (ET) is known to be involved in the regulation of root water uptake and stomatal opening although its role on plant water balance under different RH is not very well understood. We studied, at the physiological, hormonal and molecular levels (aquaporins expression, abundance and phosphorylation state), the plant responses to exogenous 1-aminocyclopropane-1-carboxylic acid (ACC; precursor of ET) and 2-aminoisobutyric acid (AIB; inhibitor of ET biosynthesis), after 24h of application to the roots of tomato wild type (WT) plants and its ET-insensitive never ripe (nr) mutant, at two RH levels: regular (50%) and close to saturation RH. Highest RH induced an increase of root hydraulic conductivity (Lpo) of non-treated WT plants, and the opposite effect in nr mutants. The treatment with ACC reduced Lpo in WT plants at low RH and in nr plants at high RH. The application of AIB increased Lpo only in nr plants at high RH. In untreated plants, the RH treatment changed the abundance and phosphorylation of aquaporins that affected differently both genotypes according to their ET sensitivity. We show that RH is critical in regulating root hydraulic properties, and that Lpo is affected by the plant sensitivity to ET, and possibly to ACC, by regulating aquaporins expression and their phosphorylation status. These results incorporate the relationship between RH and ET in the response of Lpo to environmental changes.

Weather as a risk factor for epileptic seizures: A case-crossover study.

Most epileptic seizures occur unexpectedly and independently of known risk factors. We aimed to evaluate the clinical significance of patients' perception that weather is a risk factor for epileptic seizures. Using a hospital-based, bidirectional case-crossover study, 604 adult patients admitted to a large university hospital in Central Germany for an unprovoked epileptic seizure between 2003 and 2010 were recruited. The effect of atmospheric pressure, relative air humidity, and ambient temperature on the onset of epileptic seizures under temperate climate conditions was estimated. We found a close-to-linear negative correlation between atmospheric pressure and seizure risk. For every 10.7 hPa lower atmospheric pressure, seizure risk increased in the entire study population by 14% (odds ratio [OR] 1.14, 95% confidence interval [CI] 1.01-1.28). In patients with less severe epilepsy treated with one antiepileptic medication, seizure risk increased by 36% (1.36, 1.09-1.67). A high relative air humidity of >80% increased seizure risk in the entire study population by up to 48% (OR 1.48, 95% CI 1.11-1.96) 3 days after exposure in a J-shaped association. High ambient temperatures of >20°C decreased seizure risk by 46% in the overall study population (OR 0.54, 95% CI 0.32-0.90) and in subgroups, with the greatest effects observed in male patients (OR 0.33, 95% CI 0.14-0.74). Low atmospheric pressure and high relative air humidity are associated with an increased risk for epileptic seizures, whereas high ambient temperatures seem to decrease seizure risk. Weather-dependent seizure risk may be accentuated in patients with less severe epilepsy. Our results require further replication across different climate regions and cohorts before reliable clinical recommendations can be made.

Role of Sand Grains in Sorption Processes by Surface Layers of Components of Sand Moulds

Abstract The results of researches of sorption processes of surface layers of components of sand moulds covered by protective coatings are presented in the hereby paper. Investigations comprised various types of sand grains of moulding sands with furan resin: silica sand, reclaimed sand and calcined in temperature of 700°C silica sand. Two kinds of alcoholic protective coatings were used - zirconium and zirconium - graphite. Tests were performed under condition of a constant temperature within the range 30 - 35°C and high relative air humidity 75 - 80%. To analyze the role of sand grains in sorption processes quantitavie moisture sorption with use of gravimetric method and ultrasonic method were used in measurements. The tendency to moisture sorption of surface layers of sand moulds according to the different kinds of sand grains was specified. The effectiveness of protective action of coatings from moisture sorption was analyzed as well. Knowledge of the role of sand grains from the viewpoint of capacity for moisture sorption is important due to the surface casting defects occurrence. In particular, that are defects of a gaseous origin caused by too high moisture content of moulds, especially in surface layers.

Current asthma, respiratory symptoms and airway infections among students in relation to the school and home environment in Japan

ABSTRACTObjective: To study associations between the school and home environment and current asthma, respiratory symptoms and airway infections among Japanese students. Methods: Japanese students (12–15 y) (N = 1048) in four schools responded to a questionnaire on respiratory health, allergy and the home environment. Temperature, relative air humidity (RH) and student density (students/m2 floor area) was measured in the classrooms: dust was collected from floors and in classroom air and analysed for cat (Fel d 1) and dog (Can f 1) allergens. Health associations were analysed by multi-level logistic regression. Results: Doctor's diagnosed asthma was common (13.4%), 8.8% reported cat allergy and 6.1% dog allergy. The median level in floor dust was 41 ng/g (IQR 23–92) for Fel d 1 and 101 ng/g (IQR 54–101) for Can f 1. The median level in air was 18.6 ng/ m2/ day (IQR5.9–25.1) for Fel d 1 and 18.6 ng/ m2/ day (IQR 6.0–13.3) for Can f 1. High RH, high student density and airborne cat allergen was associated with airway infections. In the home environment, recent indoor painting, new floor materials, odour, having cats as pets, window pane condensation in winter, and dampness in floor construction were associated with respiratory illness. Conclusion: High relative air humidity, high student density and airborne cat allergens at school may increase the risk of airway infections. Having cats as pets, chemical emissions from paint and new floor materials, odour and dampness can constitute domestic risk factors for respiratory symptoms while having dogs as pets could be protective.

Daily changes in VPD during leaf development in high air humidity increase the stomatal responsiveness to darkness and dry air

Previous studies have shown that plants developed under high relative air humidity (RH>85%) develop malfunctioning stomata and therefor have increased transpiration and reduced desiccation tolerance when transferred to lower RH conditions and darkness. In this study, plants developed at high RH were exposed to daily VPD fluctuations created by changes in temperature and/or RH to evaluate the potential improvements in stomatal functioning. Daily periods with an 11°C temperature increase and consequently a VPD increase (vpd: 0.36–2.37KPa) reduced the stomatal apertures and improved the stomatal functionality and desiccation tolerance of the rosette plant Arabidopsis thaliana. A similar experiment was performed with only a 4°C temperature increase and/or a RH decrease on tomato. The results showed that a daily change in VPD (vpd: 0.36–1.43KPa) also resulted in improved stomatal responsiveness and decreased water usage during growth. In tomato, the most effective treatment to increase the stomatal responsiveness to darkness as a signal for closure was daily changes in RH without a temperature increase.

Effectiveness of Protective Action of Coatings from Moisture Sorption into Surface Layer of Sand Moulds

Abstract The results of investigations of the sorption process of surface layers of sand moulds covered by zirconium and zirconium - graphite alcohol coatings are presented in the paper. Investigations comprised two kinds of sand grains (silica sand and reclaimed sand) of moulding sand with furan resin. Tests were performed under conditions of a high relative air humidity 75 - 85% and a constant temperature within the range 28 – 33°C. To evaluate the effectiveness of coatings protective action from moisture penetration into surface layers of sand moulds gravimetric method of quantitavie moisture sorption and ultrasonic method were applied in measurements. The optimal number and kind of coatings from the viewpoint of protection from moisture sorption were specified for furan moulding sands with quartz sand and reclaimed sand as well. Knowledge of proper coatings selection is important due to protection from high air humidity and its adverse effects. What is more, it can allow to select the proper storage conditions of casting moulds waiting for being poured with liquid metals. This can limit the occurrence of surface defects which are caused by too high humidity of casting moulds, especially in surface layer.

Gene expression and physiological responses associated to stomatal functioning in Rosa × hybrida grown at high relative air humidity

High relative air humidity (RH≥85%) during growth disturbs stomatal functioning, resulting in excessive water loss in conditions of high evaporative demand. We investigated the expression of nine abscisic acid (ABA)-related genes (involved in ABA biosynthesis, oxidation and conjugation) and two non-ABA related genes (involved in the water stress response) aiming to better understand the mechanisms underlying contrasting stomatal functioning in plants grown at high RH. Four rose genotypes with contrasting sensitivity to high RH (one sensitive, one tolerant and two intermediate) were grown at moderate (62±3%) or high (89±4%) RH. The sensitive genotype grown at high RH showed a significantly higher stomatal conductance (gs) and water loss in response to closing stimuli as compared to the other genotypes. Moreover, high RH reduced the leaf ABA concentration and its metabolites to a greater extent in the sensitive genotype as compared to the tolerant one. The large majority of the studied genes had a relevant role on stomatal functioning (NCED1, UGT75B2, BG2, OST1, ABF3 and Rh-APX) while two others showed a minor contribution (CYP707A3 and BG1) and AAO3, CYP707A1 and DREB1B did not contribute to the tolerance trait. These results show that multiple genes form a highly complex regulatory network acting together towards the genotypic tolerance to high RH.

English

Renewable energy benefits and disadvantages have been subject of major discussions and studies. Thus, this study aimed at assessing the smoke opacity from a farming tractor running two types of diesel, B S1800 (B0) and B S10 (B0), and ethyl biodiesel from babassu oil at two rates (B50 and B100), at six day periods (2, 6, 10 am, 2, 6 and 10 pm). The study was conducted at the Department of Agricultural Engineering of the Faculty of Agricultural and Veterinary Sciences, UNESP, in Jaboticabal - SP, Brazil. The results showed a reduced smoke opacity during daytimes of lower ambient temperature and higher air relative humidity. In addition, smoke opacity was reduced as higher rates of babassu biodiesel were added to B S1800 diesel and B S10; thus, consisting of an efficient procedure of reducing smoke opacity in farming tractor engines. Key words: Biofuel, emissions, pollutants, renewable energy, diesel engine cycle, Orbinya martiana.

Morphological and physiological responses of three plant species occurring in distinct altitudes in the Neotropical savannah

Rupestrian fields are located above 900 m of altitude and have many endangered plants. They may present patches of Campo sujo (shrub savannah), which is a phytophysiognomy commonly found in Neotropical savannah at lower altitudes. Based on the atypical occurrence of the Campo sujo area were studied the morphological and physiological responses of three plant species in two altitudinal levels. Morphology parameters, stomatal conductance, and water potential were evaluated in leaves at rainy season. Environmental conditions and physiology were taken along specific days. High-altitude area presented lower temperatures and higher air relative humidity during the day than low-altitude area. Distinct and uneven responses in the production of stomata and the caliber of the sieve and tracheal elements among plants in the two areas were observed. Stomatal conductance was normally lower than high altitude. Water potential at high altitude was lower at predawn, similar at noon, and higher at the end of the daylight. We observed different strategies among the three species, without clear anatomy pattern. The lower stomatal conductance rates at high altitude that do not follow the pattern expected for the humidity levels are found, which may be the result of strong and frequent winds and low temperature. Water potential recovery may reflect higher air humidity observed on this site.