General Response Patterns Research Articles

Evaluation of a compartmental model to describe non-esterified fatty acid kinetics in Holstein dairy cows

The dynamics of non-esterified fatty acid (NEFA) metabolism in lactating dairy cows requires quantification if we are to understand how dietary treatments and disease influence changes in body condition (adipose reserves) and the production of milk fat. Recently, Thomaseth & Pavan (2003) presented a compartmental model (Thomaseth model), which employs the pattern of plasma insulin concentrations in humans to predict the dynamic changes that occur in the plasma concentrations of glucose and NEFA during an intravenous glucose tolerance test (IVGTT). The Thomaseth model, or at least a similar model, could have potential application to the field of energy metabolism in ruminants because it would enable the estimation of parameters that describe the rates of whole body disposition of glucose, and the production and utilization of NEFA. In this study we investigated the suitability of the Thomaseth model to describe NEFA and glucose kinetics in 10 lactating Holstein-Friesian cows given a standard IVGTT in early lactation. The Thomaseth model described the general pattern of the NEFA response and, in particular, described the downward-slope and nadir in NEFA concentrations reasonably well. However, it failed to describe the initial latency period (the period before NEFA concentrations decline precipitously), and it could not describe terminal 'rebound' plateau in NEFA concentration. Because of these inherent problems, the parameters of the Thomaseth model cannot be considered to provide accurate estimates of rates of NEFA production or utilization. It is concluded that the Thomaseth model is not suitable for describing NEFA kinetics in lactating dairy cows.

Photosynthetic limitations in response to water stress and recovery in Mediterranean plants with different growth forms

* Whether photosynthesis is limited during water stress and recovery because of diffusive or biochemical factors is still open to debate, and apparent contradictions appear when various studies on species with different growth forms are compared. * Ten Mediterranean species, representing different growth forms, were subjected to different levels of water stress, the most severe followed by rewatering. A quantitative limitation analysis was applied to estimate the effects of water stress on stomatal (S(L)), mesophyll conductance (MC(L)) and biochemical limitations (B(L)). * Results confirmed a general pattern of photosynthetic response to water stress among C(3) plants when stomatal conductance (g(s)) is used as a reference parameter. As g(s) values decreased from a maximum to approx. 0.05 mol H(2)O m(-2) s(-1), the total photosynthetic limitation rose from 0 to approx. 70%, and this was caused by a progressive increase of both S(L) and MC(L) limitations, while B(L) remained negligible. When lower values of g(s) were achieved (total photosynthetic limitation increased from 70 to 100%), the contribution of S(L) declined, while MC(L) still increased and B(L) contributed significantly (20-50%) to the total limitation. * Photosynthetic recovery of severely stressed plants after rewatering showed a dominant role of MC(L), irrespective of the degree of photosynthesis recovery.

Persistent anxiety-like behavior in marmosets following a recent predatory stress condition: Reversal by diazepam

Initial investigations indicated the use of the Marmoset Predator Confrontation Test (MPCT) as an experimental procedure to measure fear/anxiety-related behaviors in non-human primates. However, possible long-term habituation effects and re-use of experimental subjects need to be verified. This study, therefore, compared the behavioral response of experienced versus naïve adult black tufted-ear marmosets ( Callithrix penicillata) in the MPCT, with/without diazepam administrations. Subjects were tested in the figure-8 maze and confronted with a taxidermized wild-cat predator stimulus. After four initial 20-min maze habituation sessions, each subject was submitted to two randomly-assigned 20-min predator confrontation sessions: vehicle and 2 mg/kg of diazepam. Confrontation with the predator induced significant behavioral changes; i.e., proximic avoidance and tsik-tsik alarm call. Diazepam administration, concomitant to predator exposure, reversed the behavioral changes observed. In both the experienced and naïve marmosets a similar behavioral profile and response pattern to diazepam was detected, corroborating the important selective pressure that felines seem to have on marmoset behavioral ecology. Therefore, during a more naturalistic-like regimen — i.e., recurring intermittent predator encounters — the general response pattern remains highly consistent, regardless of prior experience. One may consider the re-use of marmoset subjects in the MPCT, particularly under these specific conditions (i.e. repeated 20-min confrontations, 72-h apart).

On-line screening of soil VOCs exchange responses to moisture, temperature and root presence

The exchanges of volatile organic compounds (VOCs) between soils and the atmosphere are poorly known. We investigated VOC exchange rates and how they were influenced by soil moisture, temperature and the presence of plant roots in a Mediterranean forest soil. We measured VOC exchange rates along a soil moisture gradient (5%–12.5%–20%–27.5% v/v) and a temperature gradient (10°C–15°C–25°C–35°C) using PTR-MS. Monoterpenes were identified with GC-MS. Soils were a sink rather than a source of VOCs in both soil moisture and temperature treatments (−2.16 ± 0.35 nmol m−2 s−1 and −4.90 ± 1.24 nmol m−2 s−1 respectively). Most compounds observed were oxygenated VOCs like alcohols, aldehydes and ketones and aromatic hydrocarbons. Other volatiles such as acetic acid and ethyl acetate were also observed. All those compounds had very low exchange rates (maximum uptake rates from −0.8 nmol m−2 s−1 to −0.6 nmol m−2 s−1 for methanol and acetic acid). Monoterpene exchange ranged only from −0.004 nmol m−2 s−1 to 0.004 nmol m−2 s−1 and limonene and α-pinene were the most abundant compounds. Increasing soil moisture resulted in higher soil sink activity possibly due to increases in microbial VOCs uptake activity. No general pattern of response was found in the temperature gradient for total VOCs. Roots decreased the emission of many compounds under increasing soil moisture and under increasing soil temperature. While our results showed that emission of some soil VOCs might be enhanced by the increases in soil temperature and that the uptake of most soil VOCs uptake might be reduced by the decreases of soil water availability, the low exchange rates measured indicated that soil-atmosphere VOC exchange in this system are unlikely to play an important role in atmospheric chemistry.

Perception of Fricatives by Dutch and English Speakers

Two speech perception experiments explored physical and linguistic bases of similarity. Because phonological features are grounded in similarity, these experiments were thus an exploration of bases of distinctive features. Experiment 1 found that Dutch listeners rated (s) and () as more similar to each other than did American English listeners. We attributed this to a pattern of alternation in Dutch phonology involving these sounds. Experiment 1 also found that Dutch listeners rated () and (s), and () and () as more similar to each other than did American English listeners. We attributed this to lack of () in Dutch inventory of native sounds. Experiment 2 found that Dutch and American English listeners did not signficantly differ from each other in a speeded discrimination task with same stimuli as experiment 1. Reaction times in experiment 2 were highly correlated with rating data of experiment 1 (r = -.86 to -.96) indicating that general pattern of response in experiment 1 was based on auditory similarity, with language-specific effects superimposed on general pattern. We conclude that similarity, a base of phonological features, is comprised of three components: (1) auditory similarity, (2) inventory, and (3) language- specific patterns of alternation. This is a paper about similarity. By phonetic we mean a psychological phenomenon - something like the subjective experience of linguistic sound - which is no doubt related to physically measureable acoustic, visual, or motor aspects of speech sounds; but which also may be derived from listener's experience of sounds of language. We will argue on basis of data from two cross-linguistic speech perception experiments, that similarity is a product both of physical aspects of sounds and of linguistic patterning of sounds. This research is relevant to distinctive feature theory because phonological features are grounded in similarity. Phonetic similarity is relevant in poetic use of language to determine near-rhymes (Steriade, 2003), sound change is influenced by perceptibility of sounds involved in change (Hume & Johnson, 2001), and synchronic phonological patterns

The Relationship Between Serial Murder and the American Tourism Industry

Serial murder is a serious national problem, with substantial implications for tourism. In general, serial murder depresses business activity, with one important partial exceptiontourism. The present study analyzes the relationship between serial killing and public travel and tourism associated with such criminal activity. It was found that serial murder is a quantitatively significant criminal conduct, and it is increasing. The general pattern of public response to serial murder includes reduced shopping and tourism behavior, due to fear. However, serial murder also stimulates public interest in visiting serial crime sites, and numerous cases of such travel and tourism have been caused by serial murder, as documented in the present study. Typical serial murder tourism activity includes travel, sightseeing, entertainment, dining, refreshments, lodging, photo-opportunities, and the acquisition of souvenirs. Wound culture theory may explain this type of tourist behavior, which falls within the emerging genre of thanatourism.

Plasticity of sorghum kernel weight to increased assimilate availability

Understanding source or sink limitations on crop yield is critical for the rational design of agricultural practices as well as breeding strategies. In the present article, we studied sorghum [ Sorghum bicolor (L.) Moench] source–sink yield limitations during grain filling, and tested the hypothesis that the time in which kernel maximum water content is reached during grain filling defines a temporal limit for the crop to profit from source increases. Earlier studies have never tested increasing assimilate availability per kernel in different developmental stages. We conducted a field experiment increasing assimilate availability per kernel at anthesis and 15 days after anthesis in commercial hybrids. The anthesis treatment was aimed to increase assimilates per kernel from early grain filling, and the 15 days after anthesis treatment from the stage kernel maximum water content was achieved. Both treatments removed 50% of the kernels from one side of the panicle. Kernel dry weight (KW), kernel water content and kernel volume were measured in apical and basal positions of the panicle throughout grain filling. Increased assimilate availability always yielded a higher KW (∼34% increase). This KW increase was consistent across the two kernel developmental stages when the treatment was imposed, the panicle position and hybrid. Achieving maximum water content did not prevent kernels from increasing their weight when assimilates were subsequently increased. Final KW was closely related to maximum kernel volume ( r 2 = 0.72; n = 42; p < 0.0001). Increased assimilate availability per kernel promoted changes in both kernel growth rate and duration of grain filling. We applied a quantitative approach for determining the magnitude of sorghum KW changes in response to assimilate availability changes during grain filling. This allowed us to compare our data to previously published articles, and to determine any general response pattern across environments. The analysis supported our observation that sorghum KW is highly responsive to increased assimilates, and indicated that increased assimilate availability during filling always increased sorghum KW. As such, growth of sorghum kernels is predominately source limited; breeding and management practices aimed to increase assimilate availability per kernel will be likely to enhance sorghum yield. Results show that the crop has the capacity to profit from source increases even after the initial grain-filling stages have occurred.

Coping With Unemployment: Relationships Between Duration of Unemployment, Coping Styles, and Subjective Well‐Being

The present study examined whether the association between duration of unemployment and impairment in emotional and physical well‐being is mediated by a change in the general pattern of coping responses. A cross‐sectional study with 119 unemployed participants found that (1) duration of unemployment is associated with a decrease in productive coping and an increase in nonproductive coping and that (2) the association between duration of unemployment and somatic complaints is mediated by an increase in nonproductive coping. Further results showed that neuroticism and mood regulation expectancies were meaningfully related to productive and nonproductive coping. These results are discussed within the framework of theories of self‐regulation.

Seasonal contrasting changes of foliar concentrations of terpenes and other volatile organic compound in four dominant species of a Mediterranean shrubland submitted to a field experimental drought and warming

To test the effect of forecasted drought and warming conditions for the next decades by GCM and ecophysiological models on foliar concentrations of volatile organic compounds (VOCs) and especially of volatile terpenes, we studied four typical Mediterranean woody plants (Pinus halepensis L., Pistacia lentiscus L., Rosmarinus officinalis L. and Globularia alypum L.) under a field experimental drought and warming generated using automatically sliding curtains. Terpenes were detected in the four studied species (R. officinalis L., P halepensis L., Pistacia lentiscus L. and G. alypum L.). In general, maximum concentrations of terpenes were found in the coldest periods and minimum concentrations in the summer. Their concentrations ranged between 0.003 mg g−1 DM (eugenol) in G. alypum under drought conditions and 37 mg g−1 DM in R. officinalis under control conditions. Main volatile terpenes found in all studied species except in G. alypum were α‐pinene, camphene, β‐pinene, β‐phellandrene and caryophyllene. In general, VOC leaf concentrations increased when soil moisture increased and decreased when air temperature increased. However, contrasting not consistent responses to the drought and warming treatments were found among species, seasons and years. For example, in P. halepensis, the concentrations decreased in response to drought in winter and instead increased in summer. Contrarily, drought decreased concentrations in summer and increased them in winter in Pistacia lentiscus. In any case, the data on seasonal VOC concentration in Mediterranean woody species provided here will add new knowledge of seasonal variation in essential oil contents of these species. These data might help in the study of flammability of Mediterranean ecosystems and in improving prediction algorithms, inventories and modelling of monoterpene emissions in response to climate change, which mostly do not consider the changes in concentration under drought stress. However, the lack of general and consistent response patterns to increasing drought and warming among species, seasons and years found here makes this task difficult.

Responses of the Crayfish Orconectes Virilis to Chemical Cues Depend upon Flow Conditions

The responses of individuals of the crayfish Orconectes virilis to the same set of chemical cues were tested under flow (lotic) and non-flow (lentic) conditions. The cues presented to the crayfish were food cues, alarm |$\left( { = {\rm{ crushed \,\,conspecifics}}} \right)$| cues, and the combination of |${\rm{food \,\,+\,\, alarm}}$| cues. Crayfish behavior (time in burrows) and posture (lowered posture) were significantly affected by the odor treatment, the flow environment, and an interaction of treatment and environment. While the general patterns of responses to odors (more time spent feeding when food cues were introduced, and more time spent in lowered posture and in burrow when alarm cues were introduced) were qualitatively similar in the two environments, responses were stronger (especially to food odors) in the environment with flow. However, the different strength of these responses seemed not to be related to the directional information provided by the flow but rather was probably the effect of a difference in crayfish behavior between lentic and lotic environments in the control (no added chemical cues). In flow, crayfish spent less time executing feeding movements and more time in the lowered posture and in the burrow than in no-flow conditions.

The Investment Incentive Effects of Land Use Regulations

This paper provides an overview and synthesis of the results from recent studies of how different types of land use regulations affect land development incentives. The presentation is nontechnical and focuses on uncovering general principles for the dynamic effects of such policies. It explains why the risk of regulation leads to faster development of unregulated land and how the effect on structural densities reflects the underlying pattern of growth in the demand for land by competing uses. It also discusses how the general pattern of timing and density responses for regulated property reflect the same growth patterns in demand.

The Use of Wavelength‐selective Plastic Cladding Materials in Horticulture: Understanding of Crop and Fungal Responses Through the Assessment of Biological Spectral Weighting Functions

Plant responses to light spectral quality can be exploited to deliver a range of agronomically desirable end points in protected crops. This can be achieved using plastics with specific spectral properties as crop covers. We have studied the responses of a range of crops to plastics that have either (a) increased transmission of UV compared with standard horticultural covers, (b) decreased transmission of UV or (c) increased the ratio of red (R) : far-red (FR) radiation. Both the UV-transparent and R : FR increasing films reduced leaf area and biomass, offering potential alternatives to chemical growth regulators. The UV-opaque film increased growth, but while this may be useful in some crops, there were trade-offs with elements of quality, such as pigmentation and taste. UV manipulation may also influence disease control. Increasing UV inhibited not only the pathogenic fungus Botrytis cinerea but also the disease biocontrol agent Trichoderma harzianum. Unlike B. cinerea, T. harzianum was highly sensitive to UV-A radiation. These fungal responses and those for plant growth in the growth room and the field under different plastics are analyzed in terms of alternative biological spectral weighting functions (BSWF). The role of BSWF in assessing general patterns of response to UV modification in horticulture is also discussed.

Determining impacts of habitat modification on diversity of tropical forest fauna: the importance of spatial scale

Summary There is an urgent need to understand the impacts of anthropogenic habitat disturbance on biodiversity in tropical forests, but no consensus has yet emerged. We reviewed the literature for the most frequently studied taxon (birds, 37 studies) and found that increased and decreased diversity in response to disturbance (selective logging and shifting agriculture) were reported with approximately equal frequency. The spatial scale at which studies were carried out significantly affected the reported response to disturbance: studies where disturbed and undisturbed habitats were sampled at large spatial scales were more likely to report increased diversity following disturbance, whereas studies that sampled habitats at small spatial scales were more likely to report decreased diversity. These results were not a consequence of sampling method: we divided the studies into those using capture methods and those using observation methods and the same result was obtained when the analysis was restricted to only those studies using observation methods. Previously, we have shown that reported impacts of disturbance on Lepidoptera are also affected by the spatial scale of study. We reviewed the Lepidoptera literature published since then and showed that all 12 new studies conformed to the predicted pattern. While sampling scale significantly affected the reported responses of both birds and Lepidoptera, there were opposite effects of scale in the two taxa: large‐scale bird studies and small‐scale Lepidoptera studies were more likely to report increased diversity following disturbance. Bird studies were generally carried out at larger spatial scales than those of Lepidoptera and these opposite impacts of scale were probably due to a non‐linear effect of habitat disturbance on habitat heterogeneity at different spatial scales. Synthesis and applications. The rapid loss and degradation of tropical forests means that an understanding of the general patterns of responses of species to habitat disturbance is urgently needed. However, there has been little discussion of the most appropriate methods to ensure comparability of results between studies. Data presented here indicate that the spatial scale of sampling chosen in studies has a marked effect on the results obtained, and future studies need to account for this by examining explicitly the effects of disturbance at different spatial scales. The effect of spatial scale differs between taxa, and this may explain why the search for indicator taxa of disturbance effects has so far proved elusive.

MECHANISMS OF FOOD REDUCTION, TRANSPORT AND DEGLUTITION: HOW THE TEXTURE OF FOOD AFFECTS FEEDING BEHAVIOR

ABSTRACTi

A review of postglacial emergence on Svalbard, Franz Josef Land and Novaya Zemlya, northern Eurasia

The pattern of postglacial emergence in the Barents Sea is pivotal to constraining the timing of deglaciation and extent and thickness of the last ice sheet in northern Eurasia. This review unites records of Holocene relative sea level from Svalbard, Franz Josef Land, and Novaya Zemlya to better understand the geometries of past ice sheet loads. Emergence data from northern Eurasia confine the maximum area of glacier loading to the northwestern Barents Sea, where >100 m of emergence is measured on Kongsøya. Deglacial unloading commenced on western and northern Spitsbergen c. 13–12 14C ka ago, and by c. 10.5 14C ka on eastern Svalbard and more distal sites on Franz Josef Land and Novaya Zemlya. The marine limit phase (c. 13–12 14C ka) on western and northern Spitsbergen is characterized by the construction of spits indicating a dominance of long-shore drift over storm-generated fetch, reflecting extensive sea-ice coverage of coastal areas. At sites in proximity to the ice sheet margin on western and northern Spitsbergen there is evidence for a transgressive–regressive cycle c. 6–4 14C ka, possibly reflecting back migration of displaced mantle material. A modern transgression is inferred from the marine erosion of 17th century cultural features and 14C ages of whalebone and terrestrial peat buried by modern storm gravels that place sea level at its present position by c. 2 to 1 ka ago. The greatest observed emergence on Franz Josef Land occurs on Bell Island, with a marine limit at 49 m aht, formed c. >10 14C ka. Available emergence data since 9 ka show rising strandlines toward the southwest at ∼0.3 m/km. The northern limit of emergence on Franz Josef Land is poorly constrained because relative sea-level data is sparse north of 80°30′N. In contrast to Svalbard and Franz Josef Land, the marine limit on northern Novaya Zemlya is only 10–15 m above high tide and formed between 6.5 and 5.0 14C ka when global sea level was stabilizing. All sites show little apparent emergence during the past 2 ka, with the youngest raised landforms at identical heights to storm beaches. This minimal glacio-isostatic signature on Novaya Zemlya and on Vaygach Island, where deglaciation commenced >10 ka ago, indicates ice sheet thicknesses of <1.5 km. The spatial variation in emergence for the Barents Sea indicates that western and northern Spitsbergen and Novaya Zemlya were near the reactive margin of the ice sheet and these areas sustained the briefest ice coverage (2–6 ka) and were probably not in isostatic equilibrium. In contrast, central and eastern Svalbard and southern Franz Josef Land were beneath a substantial ice load and probably sustained this load for c. 10 14C ka and achieved isostatic equilibrium. Isostasy residual from an ice sheet model portrays well the general pattern of uplift and load response at the centre of ice sheets, but deviates substantial at the ice sheet margin or areas covered by thin ice, like Novaya Zemlya.

Interannual and seasonal variation in fluxes of water and carbon dioxide from a riparian woodland ecosystem

Fluxes of water, energy and carbon dioxide (CO 2) were measured using the eddy covariance technique over a mesquite ( Prosopis velutina) woodland along the San Pedro River in southeastern Arizona for the entire growing seasons of 2001 and 2002, between the last freeze event of spring and the first of fall. Although the general pattern of ecosystem response to climate forcing was similar in both years, latent heat and CO 2 fluxes showed significant variations between and within the growing seasons. The main differences between the two years were a consequence of an extended drought that lasted from October 2001 to July 2002. Most of the within season variability was attributable to the timing and magnitude of mid-summer precipitation associated with the North American Monsoon. Following new tree leaf production and prior to the monsoon onset, there was little precipitation; daytime air temperatures were high and relative humidity low. Evapotranspiration and water level data indicated that the mesquite trees always had ready access to groundwater, though they were likely supplementing this with vadose zone soil water when abundant. Nonetheless, decreases in afternoon transpiration and CO 2 uptake suggest stomatal regulation of leaf gas exchange, possibly in response to the high vapor pressure deficit. Because near-surface soil moisture was limited prior to the summer rains, ecosystem respiration was low and there was little evapotranspiration from understory plants and soil. With the arrival of the monsoon rains, understory vegetation activity and, consequently, total ecosystem evapotranspiration increased. Total ecosystem photosynthesis also increased, but the net uptake of carbon decreased, due to enhanced respiration from the abundant carbon sources, stimulated by the precipitation and warm temperatures. The nighttime measurements of CO 2 fluxes, although of questionable accuracy, imply the ecosystem was a net sink of CO 2 for most of the two growing seasons.

Application of random regression models in animal breeding

Random regression models (RRM) have become common for the analysis of longitudinal data or repeated records on individuals over time. Applications in animal breeding research are emphasized while recognizing that RRM are used in many biological situations including human health. The best known application of RRM has been to genetic evaluation of dairy cattle using test day production records. The basic structure of a RRM is given. Other applications include growth traits in all species, genotype by environment interactions, and ad hoc proposals for the analysis of survival data and fertility data. RRM allow the researcher to study changes in genetic variability with time and allow selection of individuals to alter the general patterns of response over time.

The Role of Antimicrobial Peptides in Innate Immunity

Production of antimicrobial peptides and proteins is an important means of host defense in eukaryotes. The larger antimicrobial proteins, containing more than 100 amino acids, are often lytic enzymes, nutrient-binding proteins or contain sites that target specific microbial macromolecules. The smaller antimicrobial peptides act largely by disrupting the structure or function of microbial cell membranes. Hundreds of antimicrobial peptides have been found in the epithelial layers, phagocytic cells and body fluids of multicellular animals, from mollusks to humans. Some antimicrobial peptides are produced constitutively, others are induced in response to infection or inflammation. Studies of the regulation of antimicrobial peptide synthesis in Drosophila have been particularly fruitful, and have provided a new paradigm for the analysis of mammalian host defense responses. It now appears that the general patterns of antimicrobial responses of invertebrates have been preserved in vertebrates ("innate immunity") where they contribute to host defense both independently and in complex interplay with adaptive immunity.

Impaired Visual Attention in Children with Dyslexia

Reading involves the correct and rapid identification of visual stimuli with letters and words. The processing of visual stimuli depends not only on the integrity of the peripheral and central visual system but also on the attentional systems involved. In the present study, a cue-target visual attention task was administered to a population-based sample of 25 children with dyslexia from 10 to 12 years of age. A control group matched for group size, age, and gender was obtained from the same general population. A two-stage screening process involved a spelling task of regular words followed by a battery of five single-word reading tasks. The cue-target task involved both a computer-controlled stimulus presentation and a computer-controlled measurement of reaction time. The data were analyzed by visual field, cue condition (valid, invalid, and no cue), and cue-target interval (CTI). The results showed a general pattern of slower responses in the dyslexia group compared to the control group. The dyslexia group also had longer reaction times in the short CTI condition (covert shift of attention) and in the long CTI condition (overt shift of attention). The findings may reflect a general attentional deficit to visual stimuli in dyslexia, possibly related to problems with the recruitment of necessary cognitive resources for the performance of complex reaction time tasks and for fluent reading.

Effects of light and soil water availability on leaf photosynthesis and growth of Arisaema heterophyllum, a riparian forest understorey plant.

The effects of soil-water availability on leaf light acclimation and whole-plant carbon gain were examined in Arisaema heterophyllum Blume, a riparian deciduous forest understorey plant. Photosynthesis, above-ground morphology and ramet biomass accumulation (relative growth rate: RGR of a corm for a full leaf life-span) were measured on plants raised under three light treatments combined with two soil water conditions. The two higher light treatments during growth (high: max. 550 micro mol photons m(-2) s(-1); medium: 150 micro mol photons m(-2) s(-1)) resulted in a twofold increase in RGRs, 30% higher photosynthetic capacities and 20% less photosynthetic low-light use efficiency than those under a low light condition (50 micro mol photons m(-2) s(-1)). Leaf area was the smallest and leaf mass area ratio was the largest under the high light treatment. Water stress decreased both photosynthetic rate and leaf area and, hence, RGR in all the light regimes. However, water stress did not alter the general patterns of physiological and morphological responses to different light regimes. We estimated that higher photosynthetic low-light use efficiency and larger leaf area in the low light leaf would lead to a threefold carbon gain as compared with the high light leaf under simulated low light conditions. Both experimental and simulation results suggest that the physiological and morphological acclimations tend to be beneficial to carbon gain when light availability is low, whereas they favor increased water use efficiency when light availability is sufficiently high.