Variation In Growth Rate Research Articles

Analyzing structure loss in Czochralski silicon growth: Root causes investigation through surface examination

A considerable proportion of the grown Czochralski Si ingots are remelted due to the generation of dislocations or the so-called structure loss. The assessment of the failed ingots is a crucial step toward achieving higher yield. Nonetheless, characterizing Si ingots poses a challenge attributed to their inherent high brittleness and the elevated concentration of dislocations, further complicating the cutting process. In this work, we utilize a non-destructive method to categorize the failed ingots and reveal the root causes of this failure. This study is performed on roughly 80 industrial monocrystalline silicon ingots that are grown for solar cell applications. Most of these ingots have experienced structure loss during the body growth. Analyzing the surface features reveals major categories of the structure loss ingots. Approximately, 66% of the examined ingots seem to be linked with temperature fluctuations, specifically a sudden drop in the melt temperature, and contamination by foreign particles. It is found that the primary causes can be categorized into four major groups: melt contamination, thermal fluctuations, melt vibration, and variations in growth rate. The primary root causes are identified within a fishbone diagram.

Physiological responses of Caulerpa spp. (with different dissolved inorganic carbon physiologies) to ocean acidification

ABSTRACT Caulerpa is a widely distributed genus of chlorophytes (green macroalgae) which are important for their dietary, social and coastal ecosystem value. Ocean acidification (OA) threatens the future of marine ecosystems, favouring macroalgal species that could benefit from increased seawater carbon dioxide (CO2) concentrations. Most macroalgae species possess CO2 concentrating mechanisms (CCMs) that allow active uptake of bicarbonate (HCO3 −). Those species without CCMs are restricted to using CO2, which is currently the least abundant species of dissolved inorganic carbon (DIC) in seawater. Thus, macroalgae without CCMs are predicted to be likely benefit from OA. Caulerpa is one of the rare few genera that have species both with and without CCMs. The two most common Caulerpa species in New Zealand are C. geminata (possesses a CCM) and C. brownii (non-CCM). We investigated the responses of growth, photo-physiology and DIC utilisation of C. geminata and C. brownii to four mean seawater pH treatments (8.03, 7.93, 7.83 and 7.63) that correspond to changes in pH driven by increases in pCO2 simulating future OA. There was a tendency for the mean growth rates for C. brownii (non-CCM) to increase under lower pH, and the growth rates of C. geminata (CCM) to decline with lower pH, although this was not statistically significant. However, this is likely because variability in growth rates also increased as seawater pH declined. There were few other differences in physiology of both species with pH, although there was tendency for greater preference for CO2 over HCO3 − uptake in the CCM species with declining seawater pH. This study demonstrates that DIC-use alone does not predict macroalgal responses to OA.

Exploiting fucoxanthin mono-carrier nanoparticles to modulate digestion and metabolic regulation in an obesity model

Fucoxanthin (FX), a natural compound derived from marine algae, and FX-based nanoparticles (FZ) were investigated for their potential in regulating glucose and lipid metabolism. Gavage interventions with FX, FZ, and zein hydrolysate (ZH) were administered to obese mice, resulting in significant outcomes. These interventions led to variations in growth rates, reduced blood glucose levels, improved lipid profiles, and ameliorated liver pathology. Our mRNA expression analysis revealed modulation of key genes involved in glucose metabolism. Gut analysis, including short-chain fatty acid detection and 16S rRNA gene sequencing, provided insights into gut microbiota modulation. Notably, differences observed in vivo between FX and FZ were attributed to their distinct release rates during in vitro digestion in the stomach and intestine. This comprehensive study validates our methods, modeling, and metabolic parameter determination, reinforcing the significance of our results. In conclusion, our findings highlight the promising potential of FX-encapsulated interventions in modulating metabolic pathways. Furthermore, they emphasize the crucial role of gut microbiota dynamics in the strategic mitigation of disorders associated with obesity.

EXAMINATION OF THE PHYSIOLOGICAL AND BIOCHEMICAL CHANGES AFFECTING NUTRITIONAL REQUIREMENTS THAT OCCUR IN DIFFERENT LIFE STAGES OF FISH

Fish undergo many physiological and biochemical changes throughout life, each demanding distinct nutritional consideration. This study explores the nuanced relationship between physiological and biochemical changes influencing nutritional requirements in different life stages of fish. The research involved an ethical and comprehensive investigation into various fish species' embryonic, larval, juvenile, and adult phases. Results demonstrated significant variations in growth rates, emphasizing rapid larval growth and unique reproductive hormone patterns during adulthood. Enzymatic activities reflected stage-specific digestive and metabolic demands, with larval stages exhibiting elevated digestive enzyme activities. Proximate composition analyses showcased protein, lipid, and carbohydrate content fluctuations, illustrating the evolving nutritional needs.

From Takeoff to Touchdown: A Decade’s Review of Carbon Emissions from Civil Aviation in China’s Expanding Megacities

The rapid growth of urbanization in China has led to a substantial escalation in the demand for civil aviation services, consequently propelling China to the third-largest contributor of carbon emissions within the aviation sector. Using the 2012–2021 data on takeoffs and landings of civil aviation aircraft in China, the aircraft engine emission factor database of the Base of Aircraft Data (BADA) from EUROCONTROL, this paper investigates the spatial-temporal distribution characteristics of atmospheric pollutants, primarily carbon emissions from Chinese civil aviation aircraft in 19 megacities. The results indicate that (1) China’s aviation CO2 emissions equivalent between 2012 and 2022 has been on an upward trajectory, peaking at 186.53 MT in 2019 with an average annual growth of 12.52%. The trend, albeit momentarily interrupted by the COVID-19 pandemic, appears to persist. (2) CO2 constitutes the highest proportion of aircraft emissions at 83.87%, with Cruise Climb Descent (CCD) cycle emissions accounting for 96.24%. CO2 and NOX, with the highest increase rates in the CCD and Landing and Takeoff (LTO) phases, respectively, are identified as the chief culprits in aviation-related greenhouse effects. (3) There is a marked spatial imbalance, with 19 megacities contributing 62.08% of total CO2 emissions, compared to the 207 least-emitting cities contributing just 9.29%. (4) The pattern of city carbon emissions is changing, with rapid growth rates in the western cities of Xinjiang, Tibet, Shaanxi, and Guizhou, and varied growth rates among megacities. The implications of this study emphasize the urgency for advancements in aviation fuel technology, rigorous management of CCD phase pollutants, strategic carbon emission controls in populous cities, fostering green aviation initiatives in western regions, diverse carbon mitigation tactics, and strengthening the precision and surveillance of aviation carbon accounting systems. Collectively, this study paints a grand picture of the complexities and challenges associated with China’s urban sprawl and aviation carbon emissions.

Technological Advancement and Its Impact on International Trade Dynamics: A Comprehensive Study of Bangladesh

This research delves into the intricate relationship between technological advancement and international trade dynamics in Bangladesh, a nation experiencing a burgeoning number of internet users and technological immersion. Analyzing data from a sample of 25 firms across diverse sectors, the study unveiled a potent correlation between technological adoption and firm growth. Notably, large firms in the Ready-Made Garments (RMG) and IT sectors demonstrated pronounced technological integration, positively influencing their trade growth. In contrast, the agriculture (AGRI) sector presented unique challenges, with medium and small enterprises perceiving technological assimilation as a significant barrier. Regression analyses reinforced technological adoption as a paramount determinant of growth, elucidating approximately 91.2% of the variance in firm growth rates. Despite the overarching positive trajectory, the research underscores variances in technological impact across sectors and firm sizes. Conclusively, while technology emerges as a catalyst for growth in Bangladesh's international trade, its uniform adoption and consequent benefits necessitate tailored strategies and infrastructural enhancements.

Single crystal growth of 2 in. diameter LiI:Eu in carbon coated crucible and effect of post growth thermal treatment on scintillation

This study focuses on economically and efficiently growing 2-inch diameter, 2-inch length LiI:Eu single crystals using Bridgman technique in carbon coated quartz crucible. Further, the impact of growth rate variation to expedite crystal growth is investigated and the influence of heat treatment on grown crystal and its scintillation properties is explored. Our research demonstrates more than 1.5-fold improvement in the scintillation light yield after heat treatment for the LiI:Eu crystals grown at translation rate of 2.5 mm/hr. Furthermore, more than twofold enhancement in scintillation light yield for both gamma and thermal neutron radiations in LiI:Eu crystals grown at 1 mm/hr rate is observed after vacuum heat treatment at 300 °C.

Intervention effect of freeze-dried probiotic and unripe banana pulp combination on set-type Bio-yogurt production during storage

AbstractWe structurally pinpoint a loop that investigates various probiotic properties of free and freeze-dried Levilactobacillus brevis (LAC and LACFD) in vitro including growth rate, pH, bile endurance, antibiotic sensitivity, and antagonism against food-borne pathogens. An innovative Set-type Bio-yogurt by combining Levilactobacillus brevis with unripe banana pulp was produced. Set-type Bio-yogurt treatments came in three different treatments (BYP3, BYP6, and BYP9) were created as set yogurt type enriched with 3, 6, and 9% (w/v) unripe banana pulp, respectively, while (CTY and CPYFD) served as control yogurt usingfree and freeze-dried Levilactobacillus brevis. In vitro studies demonstrated that there were no significant variations in growth rate or pH although bile had a significant influence. Furthermore, the presence of some antibiotics had a substantial impact when both free and freeze-dried probiotics were compared. The antagonistic activity against foodborne bacteria was significantly affected. Once unripe banana pulp was combined with free or freeze-dried Levilactobacillus brevis, substantial results were obtained, BYP9 has the most favorable technical properties, whereas BYP6 has the greatest overall sensory evaluation (94.4 ± 0.55 points). Therefore, we recommended combining the freeze-drying process with plants such as bananas to develop affordable strategies for surviving Levilactobacillus brevis while producing symbiotic Bio-yogurt.

Core genes of biomineralization and cis-regulatory long non-coding RNA regulate shell growth in bivalves

IntroductionBivalve molluscs are abundant in marine and freshwater systems and contribute essential ecosystem services. They are characterized by an exuberant diversity of biomineralized shells and typically have two symmetric valves (a.k.a shells), but oysters (Ostreidae), some clams (Anomiidae and Chamidae) and scallops (Pectinida) have two asymmetrical valves. Predicting and modelling the likely consequences of ocean acidification on bivalve survival, biodiversity and aquaculture makes understanding shell biomineralization and its regulation a priority. ObjectivesThis study aimed to a) exploit the atypical asymmetric shell growth of some bivalves and through comparative analysis of the genome and transcriptome pinpoint candidate biomineralization-related genes and regulatory long non-coding RNAs (LncRNAs) and b) demonstrate their roles in regulating shell biomineralization/growth. MethodsMeta-analysis of genomes, de novo generated mantle transcriptomes or transcriptomes and proteomes from public databases for six asymmetric to symmetric bivalve species was used to identify biomineralization-related genes. Bioinformatics filtering uncovered genes and regulatory modules characteristic of bivalves with asymmetric shells and identified candidate biomineralization-related genes and lncRNAs with a biased expression in asymmetric valves. A shell regrowth model in oyster and gene silencing experiments, were used to characterize candidate gene function. ResultsShell matrix genes with asymmetric expression in the mantle of the two valves were identified and unique cis-regulatory lncRNA modules characterized in Ostreidae. LncRNAs that regulate the expression of the tissue inhibitor of metalloproteinases gene family (TIMPDR) and of the shell matrix protein domain family (SMPDR) were identified. In vitro and in vivo silencing experiments revealed the candidate genes and lncRNA were associated with divergent shell growth rates and modified the microstructure of calcium carbonate (CaCO3) crystals. ConclusionLncRNAs are putative regulatory factors of the bivalve biomineralization toolbox. In the Ostreidae family of bivalves biomineralization-related genes are cis-regulated by lncRNA and modify the planar growth rate and spatial orientation of crystals in the shell.

What Do Cross-Range Germination, Growth, and Interaction Studies Reveal about the Behaviour of an Expansive Plant Species?

Understanding the invasion potential of any plant species is crucial for early detection in habitat conservation, particularly when observing their expansion within their native region. As a test species, we utilised Allium ursinum L., a dominant clonal species in early spring forest floors. We compared the species’ germination capacity in native (Hungarian) and non-native (North American) soils, its seedling growth, and competing performances with two co-occurring dominant species, Melica uniflora Retz. and Carex pilosa Scop., in ten soil types and three soil compositions, respectively. Additionally, the competitive interactions of A. ursinum with Convallaria majalis L., a species already introduced in North America, were assessed under three moisture conditions. The results revealed that A. ursinum exhibited enhanced germination in non-native soils, while its shoot growth was most vigorous in control soil. When grown in soils with different co-dominant species, A. ursinum seedlings exhibited varying growth rates, significantly influenced by solar radiation intensity. A. ursinum shoots displayed superior growth in soil collected from C. pilosa stands compared to soil originating from its own stands. Notably, A. ursinum effectively competed against C. majalis in moderate soil moisture conditions. Furthermore, increasing sand content improved the competitive ability of A. ursinum against C. pilosa and M. uniflora. Based on our findings, A. ursinum possesses an invasion potential for particular North American habitats. However, the extent of its potential is dependent upon soil and climatic conditions. Under medium moisture regime, A. ursinum might outcompete the already established C. majalis from its habitats. Additionally, it can potentially displace native species with comparable ecological characteristics, such as C. pilosa and M. uniflora, especially in loose soils. Similar cross-range seed germination, growth, and paired competition experiments with potential competitor species are highly recommended as these can not only elucidate its native range expansion but also various growth scenarios for its agricultural cultivation.

Highland and lowland forest birds differ in their feather growth rates: a multispecies test in the southwestern Palaearctic

Mountain birds face numerous challenges caused by altitude‐dependent environmental seasonality. Although elevation gradients may affect bird morphology, migration strategy and/or phenology of seasonal events (breeding and moulting), the life histories of highland compared with lowland birds have been little explored. In this study we compared the growth rate and mass of the tail feathers of six forest passerine species sampled at different elevations in the Iberian Peninsula (north) and the Maghreb (south) to assess potential differences in moult duration and feather quality between highland and lowland bird populations. As timing is crucial in seasonal environments, we also explored seasonal changes in temperature in the different study areas as a proxy for the duration of the optimal temporal windows available in summer for breeding and moulting. In addition, we compared wing configuration between highland and lowland populations, which could reflect differences in their migration strategy (migratory versus sedentary). The results showed that highland birds had less time available for breeding and moulting, longer and more concave wings, and faster feather growth rates than lowland populations, but we found no consistent patterns of variation in feather mass. These results suggest that selection might have favoured an accelerated moult and a more migratory behaviour in highland populations to cope with the reduction in the optimal temporal window as elevation increases. These patterns are similar to those observed in migratory populations moving along latitudinal gradients to breed in highly seasonal northern environments. We therefore hypothesize that elevational gradients at the southern limit of the Palaearctic could be an important driving force promoting variation in feather growth rate and wing configuration, and probably also other avian life‐history characteristics.

Revealing the Removal Mechanism of Vanadium Addition on Nitrogen Pores in 30Cr15Mo1N High‐Nitrogen Steel Ingot

The removal mechanism of vanadium addition on nitrogen pores in 30Cr15Mo1N ingot is systematically investigated through statistical analysis and theoretical calculation. The nitrogen solubility is obtained by the thermodynamic model, and the nitrogen content is obtained by combining the ProCAST software and the C–K model. Then, according to the formula of critical nucleation radius and growth rate of nitrogen bubbles, the variation of critical nucleation radius and growth rate of nitrogen bubbles with different vanadium contents is calculated. As the vanadium content increases, the number and mean area of nitrogen pores decrease. In comparison to the 0 V ingot, the number of nitrogen pores decreases in the 0.2 V ingot, but there is an increase in the number of large‐sized nitrogen pores (>3000 μm in diameter). When the vanadium content increases to 0.4, the nitrogen pores are completely removed. The results demonstrate that increasing vanadium content can remove nitrogen pores. Since the solidification mode remains unchanged with increasing vanadium content, increasing the vanadium content cannot remove nitrogen pores by changing the solidification mode of the 30Cr15Mo1N ingots. Therefore, increasing the vanadium content removes the nitrogen pores mainly by inhibiting the nucleation of nitrogen bubbles and promoting nitrogen bubble overflow in 30Cr15Mo1N ingots.

Metabolomic, lipidomic, and proteomic profiles provide insights on meat quality differences between Shitou and Wuzong geese

A comprehensive comparison of metabolomic, lipidomic, and proteomic profiles was conducted between the breast and leg muscles of Shitou goose (STE) and Wuzhong goose (WZE), which exhibit significant variations in body size and growth rate, to evaluate their impact on meat quality. WZE had higher intramuscular fat content in their breast muscles, which were also chewier and had higher drip and cooking losses than STE. Metabolomic analysis revealed differential regulation of amino acid and purine metabolism between WZE and STE. Lipidomic analysis indicated a higher abundance of PE and PC lipid molecules in WZE. Integration of proteomic and metabolomic data highlighted purine metabolism and amino acid biosynthesis as the major distinguishing pathways between STE and WZE. The primary differential pathways between breast and leg muscles were associated with energy metabolism and fatty acid metabolism. This comprehensive analysis provides valuable insights into the distinct meat quality of STE and WZE.

Unveiling a Biomarker Signature of Meningioma: The Need for a Panel of Genomic, Epigenetic, Proteomic, and RNA Biomarkers to Advance Diagnosis and Prognosis.

Meningiomas are the most prevalent primary intracranial tumors. The majority are benign but can undergo dedifferentiation into advanced grades classified by World Health Organization (WHO) into Grades 1 to 3. Meningiomas' tremendous variability in tumor behavior and slow growth rates complicate their diagnosis and treatment. A deeper comprehension of the molecular pathways and cellular microenvironment factors implicated in meningioma survival and pathology is needed. This review summarizes the known genetic and epigenetic aberrations involved in meningiomas, with a focus on neurofibromatosis type 2 (NF2) and non-NF2 mutations. Novel potential biomarkers for meningioma diagnosis and prognosis are also discussed, including epigenetic-, RNA-, metabolomics-, and protein-based markers. Finally, the landscape of available meningioma-specific animal models is overviewed. Use of these animal models can enable planning of adjuvant treatment, potentially assisting in pre-operative and post-operative decision making. Discovery of novel biomarkers will allow, in combination with WHO grading, more precise meningioma grading, including meningioma identification, subtype determination, and prediction of metastasis, recurrence, and response to therapy. Moreover, these biomarkers may be exploited in the development of personalized targeted therapies that can distinguish between the 15 diverse meningioma subtypes.

Investigation of frequency-dependent fatigue crack growth behavior in perfluorosulfonic-acid membrane: In-situ experiment, constitutive modeling and crack growth prediction

Fatigue crack growth behavior of perfluorosulfonic-acid membrane is investigated under distinct loading frequencies. The evolution of cyclic plastic zone (CPZ) is traced based on in-situ optical microscopy testing and digital image correlation (DIC) technique. The crack tip deformation process is directly observed by in-situ scanning electron microscope (SEM). The experimental results show that fatigue cracks experiencing a higher loading frequency display a comparatively reduced propagation rate. The CPZ can be solely used to interpret the fatigue crack growth rate variation under different loading frequencies. The crack-front microspores are easily formed under lower loading frequency due to the enhancement of near-tip plasticity deformation. Then, a cyclic elastic-viscoplastic constitutive model is developed, which successfully capture the mechanical behavior of the membrane. Finally, based on the plastically dissipated energy, a numerical method incorporated with the developed material’s constitutive relationship is established, which gives reasonable prediction of fatigue crack growth under various loading frequencies.

The British Ixworth: individual growth and egg production of a purebred dual-purpose chicken

ABSTRACT 1. Killing male one-day-old chicks, especially from layer lines, is banned in some European countries. Therefore, dual-purpose chickens, where each sex is used for meat and egg production, respectively, offer an alternative production solution. This study evaluated the British purebred breed Ixworth as a dual-purpose chicken for meat and egg production. 2. Ixworth chicks (n = 167) were hatched and reared mixed-sex in a floor housing system, with two groups receiving a commercial pullet diet (treatment 1) and two groups receiving a diet composed for males of layer lines (treatment 2). Individual chick performance data were recorded. Males were slaughtered at 12 weeks of age, and their growth rate and carcase variables were analysed. All hens were continuously reared on the pullet diet and kept in a free-range system from 20 weeks old for one laying period (52 weeks). In addition, group-based feed consumption and mortality were recorded. 3. Cockerels in treatment 1 and 2 showed significantly different [T(88) = −2.846, P = 0.003] growth rates (25.3 vs. 27.4 g/day) and average final weights (2166 g vs. 2344 g). The hens in treatment 1 (n = 41) laid an average of 193 eggs per hen housed (mean egg weight: 56.9 g), whereas those in treatment 2 (n = 35) laid 195 eggs per hen housed (mean egg weight: 56.5 g). Nest acceptance was >97.5% and feed consumption was up to 140 g/bird/day. 4. The results showed that the Ixworth may be a suitable breed for dual-purpose use and could be improved through selective breeding, offering potential for preservation of this local breed as well as general biodiversity in poultry farming.

Infection Causes Trade-Offs between Development and Growth in Larval Amphibians.

AbstractTrade-offs between life history traits are context dependent; they vary depending on environment and life stage. Negative associations between development and growth often characterize larval life stages. Both growth and development consume large parts of the energy budget of young animals. The metabolic rate of animals should reflect differences in growth and developmental rates. Growth and development can also have negative associations with immune function because of their costs. We investigated how intraspecific variation in growth and development affected the metabolism of larval amphibians and whether intraspecific variation in growth, development, and metabolic rate could predict mortality and viral load in larvae infected with ranavirus. We also compared the relationship between growth and development before and after infection with ranavirus. We hypothesized that growth and development would affect metabolism and predicted that each would have a positive correlation with metabolic rate. We further hypothesized that allocation toward growth and development would increase ranavirus susceptibility and therefore predicted that larvae with faster growth, faster development, and higher metabolic rates would be more likely to die from ranavirus and have higher viral loads. Finally, we predicted that growth rate and developmental rate would have a negative association. Intraspecific variation in growth rate and developmental rate did not affect metabolism. Growth rate, developmental rate, and metabolism did not predict mortality from ranavirus or viral load. Larvae infected with ranavirus exhibited a trade-off between developmental rate and growth rate that was absent in uninfected larvae. Our results indicate a cost of ranavirus infection that is potentially due to both the infection-induced anorexia and the cost of infection altering priority rules for resource allocation.

Predicting porosity distribution effects on the orientation induced plastic anisotropy of ductile solids: A crystal plasticity investigation

This paper investigates the role of crystallographic orientation and heterogeneous void distribution on void growth using three-dimensional crystal plasticity simulations. Face-centered cubic crystal structure is chosen as the model system. The role of crystallographic orientation on void growth is mapped by modeling single crystals as cubic unit cells with an embedded spherical void. Reminiscent of real aggregates, porosity is then re-distributed in single crystals to assess the role played by heterogeneous distribution of voids. Simulations are coupled with statistical analysis tools to decode the complex interplay involved in orientation dependent anisotropic plasticity and stochastic parameters governing heterogeneous void distribution like void size and placement. The applicability of the obtained results for single crystals is appraised for polycrystals as well by embedding the porous crystal in a randomly textured polycrystalline aggregate. Statistical analysis is repeated for all the considered orientations of the central grain to highlight the intricacies associated with plastic anisotropy-randomness in the heterogeneous microstructure. The results reveal interesting variations in mechanical strength, ductility and void growth rate in the three-dimensional orientation space. Analysis of configuration-property linkage reveals critical variables regulating the material strength and ductility for single crystals as well as polycrystals. Ramifications of the obtained results in designing strong and tough ductile components for practical applications are discussed.

Deficit irrigation limits almond trees’ photosynthetic productivity and compromises yields

Almond yields vary between rainfed and intensively irrigated systems, but how to match irrigation to potential productivity is unclear. Hence, we compared almond physiology under deficit (600 mm) and full (1300 mm) irrigation to identify stress indices and determine the production overheads of mismanaged watering. We hypothesized that trees alter their growth to conserve resources during drought and mitigate their hydraulic stress responses. Thus, we monitored stem water potential and stomatal conductance to characterize the hydraulic responses of trees to deficient and hydrated water conditions. Adapting the seasonal relationship between irrigation coefficients and tree water potential was also tested. Finally, soil water status and trunk development were considered physical stress indices for field conditions. Soil water depletion in deficit irrigation reduced stem water potential below − 2 MPa and checked stomatal conductance at 0.15 mol m-2 s-1 for most of the growing season. An empirical productivity model determined that, under deficit irrigation, almond trees suffer from chronic stress that limits their photosynthetic capacity to ∼14 µmol m-2 s-1. Consequently, nominal assimilation limitations (10%) in early summer manifested to 4 kg C tree-1 metabolic losses by autumn. The inter-annual vegetative limitations in deficit irrigation resulted in significant yield reductions (35%) by the second experimental season. Temporal changes in the correlations between stem water potential, stomatal conductance, and trunk contractions made it difficult to use water stress indices to make irrigation decisions. However, normalizing tree performance by phenology indicated a 960 mm irrigation that supported high yields. Further, integrating the variability in soil water with trunk dendrometry illustrated that trees could maintain constant growth between irrigation days under well-watered conditions. Hence, in commercial operations, variable growth rates and trunk contraction measures signal insufficient irrigation and could guide practical irrigation adaptations.

Elevational clines predict genetically determined variation in tropical forest seedling performance in Borneo: implications for seed sourcing to support reforestation

While much research has focused on genetic variation in plants in relation to abiotic clines in temperate and boreal forests, few studies have examined similar relationships in tropical forests. Genetic variation in desirable performance traits of trees, such as drought tolerance, fast‐growth, and carbon sequestration rates, is widely used to improve reforestation efforts in nontropical systems. However, evolutionary processes such as local adaptation are poorly understood in tropical forests making it difficult to locate desired phenotypes. To test for genetic variation in growth rate in relationship to climatic clines, we conducted a common garden study over 18 months in a nursery using four dipterocarp tree species, represented by 9–12 half‐sib families, sourced across an elevational gradient ranging from lowland to hill forests (circa 130–470 m above sea‐level) in Malaysian Borneo. We found genetic variation in growth for all four species with fast‐growing half‐sib families growing 42–88% faster than poorly performing half‐sib families. Furthermore, in three species we found that elevation of seedling origin predicted seedling performance; in Shorea fallax and S. johorensis, half‐sib families originating from low elevations performed the best. In S. argentifolia half‐sib families' seedlings from low elevations grew slowly. Because elevation is a good proxy for climate, the finding of elevational clines predicting genetic variation in growth provides evidence of evolution affecting the function of tropical tree species. Our research highlights opportunities to better understand evolutionary processes in tropical forests and to use such information to improve seed source selection in reforestation.