An introduction to the theory of NON-uniformity of hygrothermal constituent of the environment

Non-uniformity of the hygrothermal constituent of the environment (NUN) causes problems not only of hot workplaces in industry, but also in lightweight buildings, and air-conditioned and even ventilated buildings. It is almost impossible to avoid cold draughts, unilateral thermal radiation etc. in such situations. The theory and definition of NUN in space and in time, and NUN climatic (convective, radiant, perspiratory) and NUN conductive are described.     

The cost of mutualism: interactions between Trollius europaeus and its pollinating parasites

Summary Photosynthetic acclimation to 5 light environments ranging from 2 to 60% full sun was determined in Alocasia macrorrhiza, a shade tolerant species from tropical forest understories, and Colocasia esculenta, a cultivated species which occurs naturally in open marshy areas. Photosynthetic capacities of both species increased nearly 3 fold with increased photon flux density (PFD). In a given environment, however, photosynthetic capacities of C. esculenta were double those of A. macrorrhiza. Stomatal limitations explained only a small part of this difference. Respiration rates and estimated biochemical capacities increased in parallel to photosynthetic capacity. No differences were observed either between species or environments in the ratio of RuBP regeneration capacity to carboxylation capacity as determined from the CO₂ dependence response of photosynthesis. Quantum yields of both species decreased only slightly with increasing growth PFD, providing little evidence for photoinhibition at high PFD. The results are discussed in terms of the mechanisms of and limitations on acclimation in these two species.     

不同钙离子浓度对低温下降香黄檀幼苗生长及生理特性的影响

以降香黄檀（Dalbergia odorifera T.Chen）为材料,通过人工控制温度的方法,探讨在不同温度条件下施加不同浓度Ca²⁺对降香黄檀幼苗生长及生理特性的影响。结果显示：常温条件下,施加不同浓度的Ca²⁺对降香黄檀的茎高、叶长、净光合速率（P_n）、气孔导度（G_s）、蒸腾速率（T_r）和光合色素含量均有显著影响;而对叶片相对含水量、露点水势、相对电导率、丙二醛（MDA）和可溶性蛋白含量影响较小;促进生长发育的最适Ca²⁺浓度为5 mmol/L。低温对降香黄檀上述生理指标以及水分利用效率（WUE）均有显著影响;低温条件下施加不同浓度的Ca²⁺能使上述指标得到不同程度的缓解,提高降香黄檀低温胁迫耐受性的最适浓度为5 mmol/L。隶属函数分析结果表明,常温和低温条件下,外源Ca²⁺浓度对降香黄檀的调控影响依次为5、10、15、2.5 mmol/L。     

Characteristics of leucine transport by isolated hepatocytes of antarctic fish at low temperatures

Hepatocytes prepared by collagenase perfusion from Antarctic nototheniid fish of genus Trematomus are active in uptake of [¹⁴C]leucine at 0, 5, and 10°C. The system is saturable with apparent $\text{K}{}_{\mathrm{<mtext>m</mtext>}}$ about 1.0 mM. Isoleucine and phenylalanine were major competitors, valine was about one-half as effective, while alanine, glycine and histidine had no effect. Temperature dependency of rates in the 0–10°C range yielded $\text{E}{}_{\mathrm{<mtext>a</mtext>}}\text{= 65}\text{kJ/mol}$ ($\text{Q}{}_{10}\text{= 2.7}$). The average first-order rate constant at 0°C was 0.1 min^?1, one-third the value of 0.3 min^?1 estimated for clearance of [¹⁴C]leucine by liver of these species in vivo. Affinity and specificity agreed well with in vivo data on liver clearance of leucine, both in Antarctic fish at 0°C and in temperate fish acclimated to 10°C and 20°C. The results indicate similar modifications of leucine transport associated with evolutionary cold adaptation and seasonal acclimation in fish.     

The possible functional role of neuronal gangliosides in temperature adaptation of vertebrates

Comparative studies on brain gangliosides of more than 60 vertebrate species show correlations between concentration and the level of evolutionary organization: poikilothermic lower vertebrates (fish, amphibs, reptiles) contain about 110 to 700 μg ganglioside bound NeuAc/g. fresh wt., homeothermic birds and mammals, on the other side, 500 to 1000 μg. The composition of brain gangliosides in poikilotherms is much more complex and variable (more multisialogangliosides) as compared with homeotherms (domination of less polar fractions). There are distinct correlations between brain ganglioside composition and state of thermal adaptation: Fishes being adapted to habitates with extreme temperatures (antarctic icefish — tropic fish) are characterized by quite opposite ganglioside patterns (domination of high versus less polar fractions). During seasonal acclimatization and experimental acclimation of fish to cold or during hibernation and early postnatal development of mammals poly-sialylations of brain gangliosides occur. With regard to this the individual brain structures react differently.

The results are taken for evidence that variations in the composion of synaptic membrane-bound gangliosides may induce long-term alterations in viscosity and permeability of the neuronal membrane by which the neuronal transmission might be kept on a constant level during the process of temperature adaptation.     

Physiological adaptations of coccinellidae to supranivean and subnivean hibernacula

The supranivean hibernaculum of Hippodamia convergens allows exposure of this species to fluctuating temperatures and humidities. Correspondingly, H. convergens is resistant to desiccation, maintains cold-hardiness independent of temperature, and responds to warm acclimation with a reduced respiration rate. Beneath the snow, Coleomegilla maculata is maintained at a constant temperature and high humidity. Warm acclimation in this species results in a loss of cold-hardiness and an increase in respiration rate. This response suggests a transition from an energy-conserving metabolic state associated with overwintering to one of energy expenditure as the beetles prepare for summer feeding and reproduction.     

Production and energy flow in the benthic community of a Texas pond

Energy flow (A = R + P; assimilation = respiration + production) and life-history/density-biomass cycles were followed for 1 year in a mayfly (Brachycercus sp.) population and two chironomid (Procladius sp. and Tendipes decorus) populations in a 0.94 ha pond located in north-central Texas. Temperature (5, 10, 15, 20, 25 and 30°C) effects on R and patterns of metabolic compensation/acclimatization were determined for the mayfly and chironomids. Chironomid and mayfly populations dominated the nine benthic macroinvertebrates identified in the pond, with greatest abundances in winter and winter-spring respectively. Annual energy flow was 51 kcal m^–2 (R = 40 kcal, P = 11 kcal or 1.9 g) in Brachycercus sp., 23 kcal m^–2 (R = 5 kcal, P = 18 kcal or 2.4 g) in Procladius sp. and 74 kcal m^–2 (R = 17 kcal, P = 57 kcal or 6.0 g) in T. decorus. Each species metabolically compensated partially to temperatures en countered during their life histories.     

Light and temperature, but not UV radiation, affect chlorophylls and carotenoids in Norway spruce needles (Picea abies (L.) Karst.)

Concentrations of chlorophyll a/freshweight (Chl a FW) and photosynthetic pigments/chlorophyll a were studied during one growing season in the current year's (CYN) and last year's needles (LYN) from Norway spruce (Picea abies (L.) Karst.) grown under natural or close‐to‐natural climate. Climate regimes differed in photosynthetic active radiation (PAR), temperature (T) and UV‐B radiation. Pigments were not affected by UV‐B but most of the differences between climate regimes, and also seasonal variations within climate regimes, could be related to PAR and T. Generally, two types of response to climate were observed: firstly, pigments reacted primarily to PAR without marked sensitivity to T and exhibited slow response times (> 30 d), and, secondly, pigments were affected by the combined action of PAR and T and responded faster than 20 d. The Chl a FW and chlorophyll b/chloprophyll a ratio exhibited slow‐type response in CYN and fast‐type response in LYN. Higher amplitudes in CYN than in LYN were observed for the latter two parameters, which are known to be associated with levels of pigment–protein complexes. It is suggested that slow response in CYN ensures that the high investments in proteins in these needles occur only in response to longer‐lasting climate episodes.