Implementation of the Acclimatization Process for Ginger Plantlets (Zingiber officinale Roscoe)

Ginger (Zingiber officinale Roscoe) is an important culinary and medicinal spice but is rarely cultivated due to the unavailability of seeds. Given the difficulties in adapting to plantlets produced in natural environments, it is important to analyze the survival conditions of ginger plantlets. For this reason, we varied the incubation temperature and humidity as well as the substrate during the weaning phase. Then, we varied the nutrients contained in the watering solution during the hardening phase. The statistical analysis showed that physical factors and substrates significantly influenced (p < 0.0001) plantlet survival. Nutrient solutions significantly influenced the phylogenesis, rhizogenesis, and height growth of the plantlets. The suitable physical factors for good development of plantlets are a temperature of 26.54˚C and a humidity of 96.16%. The 1C2T2TC substrate (1 Compost + 2 Soil + 2 Coconut Peat) had a significant survival rate of approximately 92.5%. During hardening, the Plantzym solution promoted good growth in terms of plantlet height (0.6 cm) and good development of roots (30 roots) and leaves (03 leaves). This work will make it possible to develop a technical seed production sheet for better development of ginger cultivation in Benin.

Evaluation of Different Substrates Compositions for Acclimatization of Tissue Culture Taro Plantlets in a Propagator

Taro is cultivated in most Regions of Cameroon and it is affected by taro leaf blight disease since 2010 which has decreased its production. Lack of disease-free planting materials has been a main problem to farmers. This study was carried out at International Institute of Tropical Agriculture (IITA) Yaounde and Institute of Agricultural Research for Development (IRAD) Bambui to assess different substrates for acclimatization of tissue culture taro plantlets in apropagator. No information is available on acclimatization of Cameroonian taro plantlets in different substrates. Taro plantlets from tissue culture were acclimatised in a propagator for six weeks under different substrates, the first substrate consisted of sterile three parts of soil and one part of river sand mixed together (3:1), the second substrate consisted of sterile two parts of soil and two parts of river sand mixed together (2:2), the third substrate consisted of sterile two parts of soil, one part of rice husk and one part of river sand mixed together (2:1:1) and the fourth substrate consisted of sterile one part of soil and three parts of river sand mixed together (1:3). After acclimatisation of the different taroplantlets (Dark green petiole with small leaves (L1), Red petiole with small leaves (L2), Light green petiole with large leaves (L3) and Light green petiole with small leaves (L4) in these four substrates, it was observed that the best growth rate of plant was recorded on substrate sand + soil (1:3). The other substrates showed moderate growth of plants. Substrate sand + soil (1:3) can be recommended for acclimatization of Cameroonian taro plantlets.

Acclimatization of <i>in Vitro</i>Propagated Pineapple (<i>Ananas comosuss</i>(L.), var. Smooth cayenne) Plantlets to <i>ex Vitro</i>Condition in Ethiopia

Pineapple (Ananas comosuss, var. Smooth cayenne), which is a popular tropical fruit, is propagated vegetatively. Conventional propagation alone does not provide clean and adequate planting material demanded in Ethiopia. Recently, in vitro multiplication has become a promising technique for large-scale production. However, the acclimatization to the external environment procedure impedes the efficiency, which needs carefully optimized acclimatization techniques. We report optimized acclimatization procedures following first- and second-stage hardening methods for in vitro pineapple plantlets. Primarily, Jiffy-7 peat pellet allowed growing plants vigorously and provided above 8% survival rate over soil mix. Nevertheless, in Ethiopia, soil mix is cheaper and locally accessible. The primarily acclimatized plantlets are needed to be hardened further for better establishment and survival in the field. Black polybag and polysleeve pots filled with soil mix were evaluated in the greenhouse. A significant difference was obtained between pots for number of roots and substrate weight. Polybags had higher root number than polysleeves and saved about 27% of substrates per plant, which is a reduction of 25% of total transportation cost. Hence, the soil mix and polybags were found to be preferable over substrates and pots, for subsequent in vitro pineapple acclimatization.

Ascent schedules,acute altitude illness,and altitude acclimatization:Observations on the Yushu Earthquake

During the Yushu Earthquake on April 14,2010,a large number of rescuers from sea level or lowlands ascended to the quake areas very rapidly or rapidly less than 24 h. However,Yushu Earthquake is the highest quake in the world at altitudes between 3 750 m and 4 878 m where is a serious hypoxic environment. A high incidence of acute altitude illness was found in the unacclimatized rescuers;the mountain rescue operation changed as "rescue the rescuers". Lesson from the Yushu Earthquake is that the occurrence of acute altitude illness may be closely related to the ascent schedules. This prompted us to study the relationship between ascent rate and the incidence and severity of acute altitude illness;five different groups were compared. The first group was 42 sea level male young soldiers who ascended to quake area very rapidly within 8 h at 4 000 m;the second group was 48 sea level male young soldiers who ascended to 4 000 m rapidly less than 18 h;the third group was 66 acclimatized medical workers from 2 261 m who ascended to 4 000 m rapidly within 12 h;the fourth group was 56 Tibetan medical workers from 2 800 m who ascended to 4 000 m rapidly within 8 h;the fifth group was 50 male sea level workers who ascended to 4 000 m gradually over a period of 4 d. The results showed that the sea level rescuers ascended to 4 000 m very rapidly or rapidly had the highest incidence of acute mountain sickness (AMS) with the greatest AMS scores and the lowest arterial oxygen saturation (SaO2);the sea level workers ascended to 4 000 m gradually had moderate incidence of AMS with moderate AMS scores and SaO2 values;whereas the acclimatized and adapted rescuers had the lowest incidence of AMS,lowest AMS scores and higher SaO2;especially none AMS occurred in Tibetan rescuers. AMS score is inversely related to the ascent rate (r=-0.24,p< 0.001). Additionally,acute altitude illness is significantly influenced by altitude acclimatization. The ascent rate is inversely re- lated to the period of altitude acclimatization whereas the time of perfect recovered from AMS is positively correlated to the time taken to acclimatize. Generally,the best means of preventing acute altitude illness is slow and gradual ascent to high altitude,as this allows time for establishing altitude acclimatization and tolerance to the hypoxic environment. However,during an emergency circumstance,such as mountain rescue operation,the rescuers must rapidly ascend to high altitude,so a series of preventive strategies including pre-acclimatization,using some prophylactic drugs and oxygen supplementary are sorely necessary.

Thermogenic responses in Eurasian Tree Sparrow(Passer montanus)to seasonal acclimatization and temperature-photoperiod acclimation

Background:Small birds in temperate habitats must either migrate,or adjust aspects of their morphology,physiology and behavior to cope with seasonal change in temperature and photoperiod.It is,however,difficult to accurately measure how seasonal changes in temperature and photoperiod affect physiological processes such as basal metabolic rate(BMR)and metabolic activity.To address this problem,we collected data in each month of the year on body mass(Mb)and BMR,and conducted a series of experiments to determine the effect of temperature and photoperiod on Mb,BMR and physiological markers of metabolic activity,in the Eurasian Tree Sparrow(Passer montanus).Methods:In one experiment,we measured monthly change in Mb and BMR in a captive group of birds over a year.In another experiment,we examined the effects of acclimating birds to two different temperatures,10 and 30℃,and a long and a short photoperiod(16 h light:8 h dark and 8 h light:16 h dark,respectively)for 4 weeks.Results:We found that these treatments induced sparrows to adjust their Mb and metabolic rate processes.Acclimation to 30℃for 4 weeks significantly decreased sparrows’Mb,BMR,and energy intake,including both gross energy intake and digestible energy intake,compared to birds acclimated to 10℃.The dry mass of the liver,kidneys and digestive tract of birds acclimated to 30℃also significantly decreased,although their heart and skeletal muscle mass did not change significantly relative to those acclimated to 10℃.Birds acclimated to 30℃also had lower mitochondrial state-4 respiration(S4R)and cytochrome c oxidase(COX)activity in their liver and skeletal muscle,compared to those acclimated to 10℃.Birds acclimated to the long photoperiod also had lower mitochondrial S4R and COX activity in their liver,compared to those acclimated to the short photoperiod.Conclusions:These results illustrate the changes in morphology,physiology,and enzyme activity induced by seasonal change in temperature and photoperiod in a small temperate passerine.Both temperature and photoperiod probably have a strong effect on seasonal variation in metabolic heat production in small birds in temperate regions.The effect of temperature is,however,stronger than that of photoperiod.

Variation in metabolic enzymatic activity in white muscle and liver of blue tilapia,Oreochromis aureus,in response to long-term thermal acclimatization

The effects of rearing temperature on white muscle and hepatic phosphofructokinase （PFK）, pyruvate kinase （PK）, lactate dehydrogenase （LDH）, aspartate aminotransferase （AST） and alanine aminotransferase （ALT） were examined in fingerlings of blue tilapia, Oreochromis aureus. The experiment was conducted for 14 weeks at temperatures of 18, 22, 26, 30, and 34℃. The activity of the glycolytic enzymes PFK, PK, and LDH in white muscle increased significantly with increase in water temperature. A reverse trend was observed for these enzymes in the liver, except for LDH, which behaved in the same manner as in white muscle. Cytosolic AST and ALT activity increased in both white muscle and liver in response to warm thermal acclimatization, while a reduction in mitochondrial AST and ALT activity was noticed at high temperatures in comparison with those at a lower temperature.

CO_2, H_2O exchange and stomatal regulation of regenerated Camptotheca acuminata plantlets during ex vitro acclimatization

For finding the changes in CO2, H20 exchange and their stomatal regulation during ex vitro acclimatization of regenerated Camptotheca acuminata plantlets, the net photosynthesis rate （Pn）, respiration rate （Ro）, light compensation point （Lc） and light saturation point （Ls）, transpiration rate （Tr）, stomatal conductance （gs） and water use efficiency（WUE） were measured during 37 days of ex vitro acclimatization. The results showed that Pn sharply increased until 29 days, then slightly decreased. A substantial decrease in Lc and a substantial increase of Ls in the former two weeks were observed, indicating the light regime enlargement for effective leaf photosynthesis. Tr and gs abruptly decreased during the first week then linearly increased until 29days ex vitro acclimatization, reflecting the strong regulation effect of stomata on water changes of ex vitro acclimating plantlets. Stomatal regulation effect on CO2 exchange was different from that on water exchange, i.e. P, was almost independent of gs during the first week, while P. was significantly correlated with gs thereafter （i.e. dual patterns）. Different from dual patterns of gs-Pn relation, the Tr monotonously linearly increased with gs. Furthermore, WUE was almost independent on gs during the first week, while a marked decreasing tendency with gs was found thereafter. At the beginning of the acclimatization, WUE was mainly determined by photosynthetic capacity, while transpiration becomes a main determinant factor for WUE from 7 to 37 days＇ acclimatization.

Safety-efficiency trade-offs in the cotton xylem：acclimatization to different soil textures

The acclimatization of plant xylem to altered environmental conditions has attracted considerable attention from researchers over several decades. Plants growing in natural environments must seek a balance between water uptake and the water loss of leaves from evaporation. Thus, the adaptation of xylem to different soil textures is important in maintaining plant water balance. In this study, we investigated the xylem changes of cotton（Gossypium herbaceum L.） xylem in sandy, clay and mixed soils. Results showed that soil texture had a significant effect on xylem vessel diameter and length of stems and roots. Compared with G. herbaceum growing in the clay soil, those plants growing in the sandy soil developed narrower and shorter xylem vessels in their roots, and had a higher percentage of narrow vessels in their stems. These changes resulted in a safer（i.e. less vulnerable to cavitation）, but less-efficient water transport system when soil water availability was low, supporting the hydraulic safety versus efficiency trade-off hypothesis. Furthermore, in sandy and mixed soils, the root： shoot ratio of G. herbaceum increased twofold, which ensures the same efficiency of leaves. In summary, our finding indicates that the morphological plasticity of xylem structure in G. herbaceum has a major role in the acclimatization of this plant species to different soil textures.

Acclimatization of microalgae Arthrospira platensis for treatment of heavy metals in Yamuna River

Bioaccumulation and biosorption in microalgae are effective approaches for the removal of heavy metals(HMs)from river water.The objective of this study was to investigate the potential for use of acclimatized microalgae in the removal of HMs from the Yamuna River water as an acclimatizing medium.An active culture of Arthrospira platensis(A.platensis)was acclimatized to HMs up to a concentration of 100 mg/L.It was gradually exposed to increasing concentrations of HMs in five subsequent batches with a step increase of 20 mg/L to acclimatize live cells in the simulated Yamuna River water.The presence of high levels of HMs in the Yamuna River water caused growth inhibition.An empirical growth inhibition model was developed,and it predicted high threshold concentrations of HMs(210.7e424.5 mg/L),producing a positive specific growth rate of A.platensis.A.platensis also showed high average removal efficiencies of HMs,including 74.0%for Cu,77.0%for Cd,50.5%for Ni,76.0%for Cr,76.5%for Pb,and 63.5%for Co,from HMs-enriched Yamuna River water.The findings demonstrated that the maximum specific removal amounts of Cu,Cd,Ni,Cr,Pb,and Co were 54.0,58.0,39.0,62.8,58.9,and 45.3 mg/g,respectively.The maximum yields of the value-added products chlorophyll and phycocyanin were 2.5 mg/g(in a batch of 40 mg/L for Cd)and 1054 mg/g(in a batch of 20 mg/L for Cu),respectively.Therefore,acclimatized A.platensis was proven to be a potential microalga not only for sequestration of HMs but also for production of valuable pigments.

Experimental study on the method of efficient heat acclimatization in macaques

Twenty-eight adult macaques were divided into five groups for differenttreatments.Of these five groups,groups 1 to 3 were exposed to heat once dailyfor 10d until the rectal temperature (RT) rose to 40℃,40.8℃ and 41.6℃,respectively.The other two groups (groups 4 and 5) were exposed to heat twicedaily and every other day,respectively,until the RT of both groups reached41.6℃.The method of heat exposure to obtain the required RT was to keep themacaques in a hot chamber (Td 41℃,Tw 38℃).Before and after theacclimatization period,the macaques were given a standard high temperature testin the same environment as the heat acclimatization (HA) period until the RTrose to 41.6℃.The results revealed that the animals in groups 3 to 5 whose RTin HA increased to 41.6℃ showed a significant HA effect by prolonging the dura-tion of exposure (P【0.05～0.001) and decreasing the RT (1.14～1.83℃),especiallyin the daily exposed group.Therefore,one of the most effective ways for devel-oping full acclimatization in macaques is to expose to heat once daily for 10duntil the RT rises to 41.6℃.

Rooting and acclimatization of in vitro plantlets of mtl-D gene modified Robinia pseudoacacia 'Idaho'

Robinia pseudoacacia ‘Idaho＇ （Robinia x ambigua ‘Idahoensis＇, R. pseudoacacia x R. viscosa） modified by a mtLD gene went through five lines and had characteristics of drought tolerance. Three stages of their micropropagation had been studied by pre- vious investigators. The other two stages, in vitro shoot rooting and plantlet acclimatization, still remained unsolved in the laboratory. For this paper, we studied the later two stages based on the previous achievements. Results showed that the highest rooting rate of Idaho locust was 98.4% when the in vitro shoots, over 2.5 cm in height and 0.08 cm in diameter, were placed on a half strength MS basal medium with 0.4 mg.U1 IBA and 0.1 mg＇U1 NAA as supplements and were solidified with 0.5% agar; the highest survival rate was 98.3% when the rooted plantlets were potted in vermiculite. All the stages for micropropagation of the Idaho locust, modified by the mtl-D gene, were assembled completely. The tissue culture plants grow well in the field.

Effect of natural and synthetic growth stimulators on <i>in vitro</i>rooting and acclimatization of common ash (<i>Fraxinus excelsior</i>L.) microplants

Application of growth stimulators can be especially effective on plantlets in vitro of tree species which are usually worse rooted and adapted in comparison with annual plants. In our work we evaluate effects of natural (dihydroquercetin, Zircon) and synthetic growth stimulators (Melafen, Fumar, Epin-Extra) on rooting and acclimatization of common ash (Fraxinus excelsior L.) microplants. The 0.05% -?0.2% Zircon and 10-5%?Melafen enhanced in vitro rooting by 29% -?37% and 31%, respectively. Melafen also stimulated root formation faster compared to control plants. The dihydroquercetin concentration of 0.01% increased rooting by 24% and root number per shoot by 1.8 times. In vitro plants rooted on media supplemented with Melafen, Fumar and Zircon demonstrated enhanced ability to adapt to non-sterile conditions and accelerated growth. Two months after planting to the greenhouse, plants rooted on 0.01% dihydroquercetin were 45% taller than the control. Weekly spraying of plantlets with 0.02% Epin-Extra containing 24-epibrassinolid stimulated growth of uniform plants with large leaves. The obtained results support the use of growth stimulators for application in clonal micropropagation of common ash both for large-scale production of planting stock and for conservation of rare and valuable genotypes.

Influence of Watering Solution and Phenotype on the Growth of <i>in Vitro</i>Propagated Pineapple (Smooth Cayenne Cultivar) Plantlets during Acclimatization

Pineapple is the first fruit crop cultivated in south Benin that greatly contributes for food and nutritional security and farmers’ income. But the lack of homogenous planting material constitutes the major constraint for improving pineapple yield. In vitro micropropagation is now used in the production of homogenous and free disease planting materials of pineapple. However, the acclimatization to natural condition of pineapple plantlets is an important step in planting material production of this crop. Here, we determined the intrinsic and extrinsic factors which influence the behavior of plantlets during the acclimatization process. For this purpose, plantlets from different categories were selected, trimmed and planted on a horticultural substrate made up of potting soil, white sawdust and compost previously sterilized. The plantlets were then incubated in under acclimatization greenhouse with average temperature of 29˚C and 70.2% of humidity. A batch of plantlets was subjected to two different watering solutions: Shive and Robbins solution and NPK 14-6-5 foliar fertilizer. The results obtained initially showed high rate (100%) of survival and growth of the plantlets watered with Shive and Robbins solution against 50% of the plantlets watered with the foliar fertilizer solution. In addition, the plantlets with spread pores exhibiting the characteristics of which the number of leaves varies between 9 and 11, the weight between 1.2 and 1.5 g, the size of 4.5 to 5.5 cm, and a good junction between the aerial part and the root system were those which were successfully grown in acclimatization phase under greenhouse, unlike plantlets with erected pores having lower success rate. This study goes a long way in providing good procedures of acclimatization of homogenous and free disease planting material of pineapple to the famers.

Daytime Heat Stress, Thermal Pattern, Hyperthermia and Body Caloric Overload in Tropical Acclimatized Holstein and Jersey Heifers

The influence of daytime tropical heat stress in the summer was studied in Holstein and Jersey heifers already acclimatized to tropical environments to determine their physiological response based on body thermal patterns and respiratory alterations according to psychrometric caloric indicators. Daytime psychrometric elements showed a tropical caloric potential for developing moderate to severe heat stress in dairy cattle. Body temperature and respiratory rate increased in both breeds open and pregnant (P < 0.01). Thermal body overload and respiratory works increased from 09 am to 12 md (P < 0.001);reaching and sustaining hyperthermia under the highest caloric pressure from 12 md to 03 pm. Rectal temperature increased +1.5˚C in open Holstein (OH), +1.3˚C in pregnant Holstein (PH), +0.8˚C in open jersey (OJ) and +0.8˚C in pregnant Jersey (PJ). The lowest heat stress index (HSI) was at 06 am, where OH and PH showed a HIS +2.25 and +2.30 and OJ and PJ +2.34 and +2.38. Maximum heat stress occurred at 12 md where OH averaged +3.28 and Pregnant Holsteins showed +3.85 at 03 pm. Open Jersey (OJ) showed a maximum HSI at 12 md (3.54) and PJ resulted in +3.89 at 03 pm. Open and pregnant Jersey heifers were more tolerant to heat stress based on lower body mass, insulation, feed consumption and greater relation between body surface and metabolic body size for thermolysis. Acclimatization between five and twenty-five months under tropical heat stress allowed Holstein and Jersey heifers to develop thermal tolerance. Middle thermal acclimatization lowered thermal sensitivity, hyperthermia and hyperpnea in Holstein and Jersey heifers in the morning;however, pregnant heifers in both breeds showed higher thermal alteration in the afternoon. Tropical acclimatization at low altitudes could be integrated with environmental improvements and nutritional and health management to reduce influences of severe heat stress and improve physiological comfort and welfare in Holstein and Jersey heifers in the summer. Those combined strategies will reduce daytime thermal and respiratory responses and allow growth, pregnancy and health with lower body heat overload and less hyperthermia.

Liver mitochondrial and whole-animal level metabolic compensation in a catfish during seasonal acclimatization

To examine whether metabolic compensation during seasonal acclimatization at the liver mitochondrial level is consistent with that at the whole-animal level, respiration rates of liver mitochondria and resting metabolic rates in winter- and sum- meracclimatized southern catfish （Silurus meridionalis Chen） were measured. At 12.5, 17.5, 22.5, 27.5 and 32.5~C, the mean values of state 3 respiration rates were 12.21, 13.84, 18.96, 24.78 and 32.01 nmol O2min-1 mg-1 mitochondrial protein in the winter group, and 8.56, 9.20, 17.32, 22.74 and 26.32 nmol 02 min-1 mgq in the summer group, respectively. At the five assay temperatures the resting metabolic rates were 24.86, 42.68, 61.59, 84.10 and 125.65 mg 02 h-1 kgI body mass in the winter group, and 22.89, 40.59, 52.94, 75.13 and 109.35 mg Oz h-1 kg-1 in the summer group, respectively. Total mitochondrial respiration rates in the liver organ were estimated based on state 3 respiration rates, mitochondrial protein content and organ mass, and the mean values were 72.96, 71.87, 112.47, 167.35 and 183.27 nmol Ozmin-lin the winter group, and were 47.89, 47.39, 105.67, 138.18 and 132.29 nmol 02 min-1 in the summer group, respectively. Metabolic compensation caused by seasonal acclimatization occurred at the liver mitochondrial level and compensation at the liver organ level was found to be more efficient because of an in- crease in metabolic capacity of mitochondria and a boost in organ mass. Metabolic compensation at the whole-animal level was not detected. During seasonal acclimatization, the effect of metabolic compensation at liver mitochondrial level is inconsistent with that at the whole-animal level in the southern catfish. This may be due to different degrees of regulation of metabolic mechanisms among various tissues and organs in an acclimatized organism

Using Composite Phenotypes to Reveal Hidden Physiological Heterogeneity in High-Altitude Acclimatization in a Chinese Han Longitudinal Cohort

Altitude acclimatization is a human physiological process of adjusting to the decreased oxygen availability.Since several physiological processes are involved and their correlations are complicated,the analyses of single traits are insufficient in revealing the complex mechanism of high-altitude acclimatization.In this study,we examined these physiological responses as the composite phenotypes that are represented by a linear combination of physiological traits.We developed a strategy that combines both spectral clustering and partial least squares path modeling(PLSPM)to define composite phenotypes based on a cohort study of 883 Chinese Han males.In addition,we captured 14 composite phenotypes from 28 physiological traits of high-altitude acclimatization.Using these composite phenotypes,we applied k-means clustering to reveal hidden population physiological heterogeneity in high-altitude acclimatization.Furthermore,we employed multivariate linear regression to systematically model(Models 1 and 2)oxygen saturation(SpO_(2))changes in high-altitude acclimatization and evaluated model fitness performance.Composite phenotypes based on Model 2 fit better than single trait-based Model 1 in all measurement indices.This new strategy of using composite phenotypes may be potentially employed as a general strategy for complex traits research such as genetic loci discovery and analyses of phenomics.

Hypoxia Conditioning for High-Altitude Pre-acclimatization Martin

Purpose Main purposes of pre-acclimatization by hypoxia conditioning(HC)are the prevention of high-altitude illnesses and maintenance of aerobic exercise performance.However,robust evidence for those effects or evidence-based guidelines for exposure strategies,including recommendations to ensure safety,are largely lacking.Therefore,we summarize the current knowledge on the physiology of acclimatization to hypoxia and HC with the aim to derive implications for pre-acclimatization strategies before going on high-altitude treks and expeditions.Methods Based on the literature search and personal experience,core studies and important observations have been selected in order to present a balanced view on the current knowledge of high-altitude illnesses and the acclimatization process,specifically focusing on pre-acclimatization strategies by HC.Results and Conclusions It may be concluded that in certain cases even short periods(e.g.,7 h)of pre-acclimatization by HC are effective,but longer periods(e.g.,>60 h)are needed to elicit more robust effects.About 300 h of HC(intermittently applied)may be the optimal preparation for extreme altitude sojourns,although every additional hour spent in hypoxia may confer further benefits.The inclusion of hypobaric exposures(i.e.,real altitude)in pre-acclimatization protocols could further increase their efficacy.The level of simulated altitude is progressively increased or individually adjusted ideally.HC should not be terminated earlier than 1-2 weeks before altitude sojourn.Medical monitoring of the pre-acclimatization program is strongly recommended.

North-South Comparatism:New Worldism,Theories of Lack and Acclimatization

In this essay I will use the expression New Worldism to refer to a particular representation of the New World,developed in Europe.I will take some theories related to this expression(theories of lack and acclimatization)to provide a short introduction to them,taking into special consideration their connection to comparatism as it was developed in 19th-century Brazil.

The first cavefish in the Dinaric Karst?Cave colonization made possible by phenotypic plasticity in Telestes karsticus

Cave animals are an excellent model system for studying adaptive evolution.At present,however,little is known about the mechanisms that enable surface colonizers to survive in the challenging environment of caves.One possibility is that these species have the necessary genetic background to respond with plastic changes to the pressures of underground habitats.To gain insight into this process,we conducted a comparative study with the fish species Telestes karsticus,which occurs in a hydrological system consisting of an interconnected stream and a cave.Results showed that T.karsticus resided year-round and spawned in Sušik cave,making it the first known cavefish in the Dinaric Karst.Cave and surface populations differed in morphological and physiological characteristics,as well as in patterns of gene expression without any evidence of genetic divergence.To test whether observed trait differences were plastic or genetic,we placed adult fish from both populations under light/dark or constant dark conditions.Common laboratory conditions erased all morphometric differences between the two morphs,suggesting phenotypic plasticity is driving the divergence of shape and size in wild fish.Lighter pigmentation and increased fat deposition exhibited by cave individuals were also observed in surface fish kept in the dark in the laboratory.Our study also revealed that specialized cave traits were not solely attributed to developmental plasticity,but also arose from adult responses,including acclimatization.Thus,we conclude that T.karsticus can adapt to cave conditions,with phenotypic plasticity playing an important role in the process of cave colonization.