Andy Leigh | University of Technology Sydney (original) (raw)
Papers by Andy Leigh
Most plant thermal tolerance studies focus on single critical thresholds, which are arbitrary and... more Most plant thermal tolerance studies focus on single critical thresholds, which are arbitrary and phenomenological, limiting the generality of findings across studies. In animals and microbes, thermal tolerance landscapes describe the more realistic, cumulative effects of temperature. We tested this in plants by measuring the decline in leaf photosynthetic efficiency (F/F) of two species following a combination of temperatures and exposure times. As predicted by the thermal tolerance landscape framework, we demonstrate that a general relationship between stressful temperatures and exposure durations can be effectively employed to quantify and compare heat tolerance within and across plant species and over time. We also show how F/F curves translate to natural conditions, suggesting that natural environmental temperatures often impair photosynthetic function. Our findings provide more robust descriptors of heat tolerance in plants, and suggest that heat tolerance in disparate groups ...
Functional Plant Biology
Heatwaves are increasingly occurring out-of-season, which may affect plants not primed for the ev... more Heatwaves are increasingly occurring out-of-season, which may affect plants not primed for the event. Further, heat stress often coincides with water and/or nutrient stress, impairing short-term physiological function and potentially causing downstream effects on reproductive fitness. We investigated the response of water-stressed arid-zone Solanum oligacanthum and Solanum orbiculatum to spring vs summer heat stress under differing nutrient conditions. Heat stress events were imposed in open-topped chambers under in situ desert conditions. To assess short-term impacts, we measured leaf photosystem responses (Fv/Fm) and membrane stability; long-term effects were compared via biomass allocation, visible damage, flowering and fruiting. Plants generally fared more poorly following summer than spring heat stress, with the exception of Fv/Fm. Summer heat stress caused greater membrane damage, reduced growth and survival compared with spring. Nutrient availability had a strong influence on...
bioRxiv (Cold Spring Harbor Laboratory), Jun 18, 2023
Traits with intuitive names, a clear scope and explicit description are essential for all trait d... more Traits with intuitive names, a clear scope and explicit description are essential for all trait databases. Reanalysis of data from a single database, or analyses that integrate data across multiple databases, can only occur if researchers are confident the trait concepts are consistent within and across sources. The lack of a unified, comprehensive resource for plant trait definitions has previously limited the utility of trait databases. Here we describe the AusTraits Plant Dictionary (APD), which extends the trait definitions included in the new trait database AusTraits. The development process of the APD included three steps: review and formalisation of the scope of each trait and the accompanying trait description; addition of trait meta-data; and publication in both human and machine-readable forms. Trait definitions include keywords, references and links to related trait concepts in other databases, and the traits are grouped into a hierarchy for easy searching. As well as improving the usability of AusTraits, the Dictionary will foster the integration of trait data across global and regional plant trait databases.
Plant Cell and Environment, 2017
Plant Ecology
Elevated tree mortality and reduced recruitment of new trees linked to drought and fires has been... more Elevated tree mortality and reduced recruitment of new trees linked to drought and fires has been reported across a range of forests over the last few decades. Forests that resprout new foliage epicormically from buds beneath the bark are considered highly resilient to disturbance, but are potentially at risk of elevated mortality, demographic shifts and changes to species composition due to synergistic effects of drought and fire. Despite this, the effects of drought-fire interactions on such forests remain largely unknown. We assessed the effects of drought severity and fire frequency on juvenile mortality, post-fire seedling recruitment and replacement of juvenile trees (balance of recruitment minus mortality) following fire. We compared dry ridgetops and wet gullies (i.e. two forest types that inhabit different topographic positions in the landscape) across a temperate forest in southern Australia. Both forest types experienced higher rates of fire-induced juvenile mortality in ...
Journal of Visualized Experiments
IDEAcology is an interface to complement and streamline the IDEA protocol for structured, iterati... more IDEAcology is an interface to complement and streamline the IDEA protocol for structured, iterative expert elicitation
Dataset supporting a broad systematic review of studies of thermal tolerance in land plants. The ... more Dataset supporting a broad systematic review of studies of thermal tolerance in land plants. The dataset contains information from the articles that met inclusion criteria from a systematic review of >21,000 papers. The papers were screened and retained if these were investigations into tolerance of leaves or leaf-buds of angiosperms and gymnosperms exposed to potentially damaging high or low temperature events as distinct from growth conditions. We recorded meta-data of the reference, authors, title, journal, publication year and extracted data for each use of technique to measure thermal tolerance of photosynthetic tissues. A key to the type of extracted data is provided in the dataset and further information will be available in the published article and its supporting information.
Background Scientific writing is a fundamental professional skill but remains a daunting task for... more Background Scientific writing is a fundamental professional skill but remains a daunting task for the trainee scientist. Understanding, synthesising and integrating research are essential writing skills; however, appropriate use of the literature continues to be problematic with many students accidentally plagiarising because they lack paraphrasing and citation skills (Devlin & Gray, 2007). Materials to support students in developing these skills tend to be decontextualized, generic, and even ignored if presented without providing opportunities for hands-on training (Bretag, Mahmud, Wallace, Walker, McGowan, East, Green, Partridge & James, 2014). As writing scientific reports accounts for a substantial proportion of most undergraduate science assessments, discipline-specific academic literacy resources must be embedded early in the science curriculum. Aims Our aim was to design and embed a flipped, interactive academic integrity module (AIM) for a large core first year biology subje...
Departmental sources Background: miR-181a is a small non-coding RNA known to be dysregulated in o... more Departmental sources Background: miR-181a is a small non-coding RNA known to be dysregulated in osteoarthritis (OA), but the role of miR-181a in human OA remains unclear. The aim of this study was to identify its function and molecular target in chondrocytes during OA pathogenesis. Material/Methods: The function of miR-181a was assessed by gain-of-function studies in human OA chondrocytes. Potential targets of miR-181a were predicted using series of bioinformatics and intersection analysis, then confirmed by luciferase reporter assay. Gene expression was quantified using quantitative reverse transcription PCR (qRT-PCR) assays, and protein production was quantified by Western blot analysis. Results: The FITC apoptosis assay results indicated that the upregulation of miR-181a led to an increase of apoptosis rate in chondrocytes. Then bioinformatic analysis identified potential target sites of the miR-181a located in the 3' untranslated region of GPD1L. Dual-luciferase reporter assays results showed that GPD1L is a target gene of miR-181a. Furthermore, Western blot and qRT-PCR analysis demonstrated that miR-181a inhibited GPD1L gene expression. Increased GPD1L and decreased miRNA-181a were observed in tissues from osteoarthritis patients. Moreover, we found a highly negative correlation between miRNA-181a and GPD1L. Conclusions: Our results demonstrated that miR-181a may play an important role in the pathogenesis of OA through targeting GPD1L and regulating chondrocyte apoptosis.
SSRN Electronic Journal, 2021
Elevated tree mortality and reduced recruitment of new trees linked to drought and fires has been... more Elevated tree mortality and reduced recruitment of new trees linked to drought and fires has been reported across a range of forests over the last few decades. Forests that resprout new foliage epicormically from buds beneath the bark are considered highly resilient to disturbance, but are potentially at risk of elevated mortality, demographic shifts and changes to species composition due to synergistic effects of drought and fire. Despite this, the effects of drought-fire interactions on such forests remain largely unknown. We assessed the effects of drought severity and fire frequency on juvenile mortality, post-fire seedling recruitment and replacement of juvenile trees (balance of recruitment minus mortality) following fire. We compared dry ridgetop and wet gully assemblages across a temperate forest in southern Australia. Both forest types experienced higher rates of fire-induced juvenile mortality in areas that had experienced severe drought compared to moderate drought, thoug...
Scientific Data, 2021
We introduce the AusTraits database - a compilation of values of plant traits for taxa in the Aus... more We introduce the AusTraits database - a compilation of values of plant traits for taxa in the Australian flora (hereafter AusTraits). AusTraits synthesises data on 448 traits across 28,640 taxa from field campaigns, published literature, taxonomic monographs, and individual taxon descriptions. Traits vary in scope from physiological measures of performance (e.g. photosynthetic gas exchange, water-use efficiency) to morphological attributes (e.g. leaf area, seed mass, plant height) which link to aspects of ecological variation. AusTraits contains curated and harmonised individual- and species-level measurements coupled to, where available, contextual information on site properties and experimental conditions. This article provides information on version 3.0.2 of AusTraits which contains data for 997,808 trait-by-taxon combinations. We envision AusTraits as an ongoing collaborative initiative for easily archiving and sharing trait data, which also provides a template for other nationa...
Most plant thermal tolerance studies focus on single critical thresholds, which are arbitrary and... more Most plant thermal tolerance studies focus on single critical thresholds, which are arbitrary and phenomenological, limiting the generality of findings across studies. In animals and microbes, thermal tolerance landscapes describe the more realistic, cumulative effects of temperature. We tested this in plants by measuring the decline in leaf photosynthetic efficiency (F/F) of two species following a combination of temperatures and exposure times. As predicted by the thermal tolerance landscape framework, we demonstrate that a general relationship between stressful temperatures and exposure durations can be effectively employed to quantify and compare heat tolerance within and across plant species and over time. We also show how F/F curves translate to natural conditions, suggesting that natural environmental temperatures often impair photosynthetic function. Our findings provide more robust descriptors of heat tolerance in plants, and suggest that heat tolerance in disparate groups ...
Functional Plant Biology
Heatwaves are increasingly occurring out-of-season, which may affect plants not primed for the ev... more Heatwaves are increasingly occurring out-of-season, which may affect plants not primed for the event. Further, heat stress often coincides with water and/or nutrient stress, impairing short-term physiological function and potentially causing downstream effects on reproductive fitness. We investigated the response of water-stressed arid-zone Solanum oligacanthum and Solanum orbiculatum to spring vs summer heat stress under differing nutrient conditions. Heat stress events were imposed in open-topped chambers under in situ desert conditions. To assess short-term impacts, we measured leaf photosystem responses (Fv/Fm) and membrane stability; long-term effects were compared via biomass allocation, visible damage, flowering and fruiting. Plants generally fared more poorly following summer than spring heat stress, with the exception of Fv/Fm. Summer heat stress caused greater membrane damage, reduced growth and survival compared with spring. Nutrient availability had a strong influence on...
bioRxiv (Cold Spring Harbor Laboratory), Jun 18, 2023
Traits with intuitive names, a clear scope and explicit description are essential for all trait d... more Traits with intuitive names, a clear scope and explicit description are essential for all trait databases. Reanalysis of data from a single database, or analyses that integrate data across multiple databases, can only occur if researchers are confident the trait concepts are consistent within and across sources. The lack of a unified, comprehensive resource for plant trait definitions has previously limited the utility of trait databases. Here we describe the AusTraits Plant Dictionary (APD), which extends the trait definitions included in the new trait database AusTraits. The development process of the APD included three steps: review and formalisation of the scope of each trait and the accompanying trait description; addition of trait meta-data; and publication in both human and machine-readable forms. Trait definitions include keywords, references and links to related trait concepts in other databases, and the traits are grouped into a hierarchy for easy searching. As well as improving the usability of AusTraits, the Dictionary will foster the integration of trait data across global and regional plant trait databases.
Plant Cell and Environment, 2017
Plant Ecology
Elevated tree mortality and reduced recruitment of new trees linked to drought and fires has been... more Elevated tree mortality and reduced recruitment of new trees linked to drought and fires has been reported across a range of forests over the last few decades. Forests that resprout new foliage epicormically from buds beneath the bark are considered highly resilient to disturbance, but are potentially at risk of elevated mortality, demographic shifts and changes to species composition due to synergistic effects of drought and fire. Despite this, the effects of drought-fire interactions on such forests remain largely unknown. We assessed the effects of drought severity and fire frequency on juvenile mortality, post-fire seedling recruitment and replacement of juvenile trees (balance of recruitment minus mortality) following fire. We compared dry ridgetops and wet gullies (i.e. two forest types that inhabit different topographic positions in the landscape) across a temperate forest in southern Australia. Both forest types experienced higher rates of fire-induced juvenile mortality in ...
Journal of Visualized Experiments
IDEAcology is an interface to complement and streamline the IDEA protocol for structured, iterati... more IDEAcology is an interface to complement and streamline the IDEA protocol for structured, iterative expert elicitation
Dataset supporting a broad systematic review of studies of thermal tolerance in land plants. The ... more Dataset supporting a broad systematic review of studies of thermal tolerance in land plants. The dataset contains information from the articles that met inclusion criteria from a systematic review of >21,000 papers. The papers were screened and retained if these were investigations into tolerance of leaves or leaf-buds of angiosperms and gymnosperms exposed to potentially damaging high or low temperature events as distinct from growth conditions. We recorded meta-data of the reference, authors, title, journal, publication year and extracted data for each use of technique to measure thermal tolerance of photosynthetic tissues. A key to the type of extracted data is provided in the dataset and further information will be available in the published article and its supporting information.
Background Scientific writing is a fundamental professional skill but remains a daunting task for... more Background Scientific writing is a fundamental professional skill but remains a daunting task for the trainee scientist. Understanding, synthesising and integrating research are essential writing skills; however, appropriate use of the literature continues to be problematic with many students accidentally plagiarising because they lack paraphrasing and citation skills (Devlin & Gray, 2007). Materials to support students in developing these skills tend to be decontextualized, generic, and even ignored if presented without providing opportunities for hands-on training (Bretag, Mahmud, Wallace, Walker, McGowan, East, Green, Partridge & James, 2014). As writing scientific reports accounts for a substantial proportion of most undergraduate science assessments, discipline-specific academic literacy resources must be embedded early in the science curriculum. Aims Our aim was to design and embed a flipped, interactive academic integrity module (AIM) for a large core first year biology subje...
Departmental sources Background: miR-181a is a small non-coding RNA known to be dysregulated in o... more Departmental sources Background: miR-181a is a small non-coding RNA known to be dysregulated in osteoarthritis (OA), but the role of miR-181a in human OA remains unclear. The aim of this study was to identify its function and molecular target in chondrocytes during OA pathogenesis. Material/Methods: The function of miR-181a was assessed by gain-of-function studies in human OA chondrocytes. Potential targets of miR-181a were predicted using series of bioinformatics and intersection analysis, then confirmed by luciferase reporter assay. Gene expression was quantified using quantitative reverse transcription PCR (qRT-PCR) assays, and protein production was quantified by Western blot analysis. Results: The FITC apoptosis assay results indicated that the upregulation of miR-181a led to an increase of apoptosis rate in chondrocytes. Then bioinformatic analysis identified potential target sites of the miR-181a located in the 3' untranslated region of GPD1L. Dual-luciferase reporter assays results showed that GPD1L is a target gene of miR-181a. Furthermore, Western blot and qRT-PCR analysis demonstrated that miR-181a inhibited GPD1L gene expression. Increased GPD1L and decreased miRNA-181a were observed in tissues from osteoarthritis patients. Moreover, we found a highly negative correlation between miRNA-181a and GPD1L. Conclusions: Our results demonstrated that miR-181a may play an important role in the pathogenesis of OA through targeting GPD1L and regulating chondrocyte apoptosis.
SSRN Electronic Journal, 2021
Elevated tree mortality and reduced recruitment of new trees linked to drought and fires has been... more Elevated tree mortality and reduced recruitment of new trees linked to drought and fires has been reported across a range of forests over the last few decades. Forests that resprout new foliage epicormically from buds beneath the bark are considered highly resilient to disturbance, but are potentially at risk of elevated mortality, demographic shifts and changes to species composition due to synergistic effects of drought and fire. Despite this, the effects of drought-fire interactions on such forests remain largely unknown. We assessed the effects of drought severity and fire frequency on juvenile mortality, post-fire seedling recruitment and replacement of juvenile trees (balance of recruitment minus mortality) following fire. We compared dry ridgetop and wet gully assemblages across a temperate forest in southern Australia. Both forest types experienced higher rates of fire-induced juvenile mortality in areas that had experienced severe drought compared to moderate drought, thoug...
Scientific Data, 2021
We introduce the AusTraits database - a compilation of values of plant traits for taxa in the Aus... more We introduce the AusTraits database - a compilation of values of plant traits for taxa in the Australian flora (hereafter AusTraits). AusTraits synthesises data on 448 traits across 28,640 taxa from field campaigns, published literature, taxonomic monographs, and individual taxon descriptions. Traits vary in scope from physiological measures of performance (e.g. photosynthetic gas exchange, water-use efficiency) to morphological attributes (e.g. leaf area, seed mass, plant height) which link to aspects of ecological variation. AusTraits contains curated and harmonised individual- and species-level measurements coupled to, where available, contextual information on site properties and experimental conditions. This article provides information on version 3.0.2 of AusTraits which contains data for 997,808 trait-by-taxon combinations. We envision AusTraits as an ongoing collaborative initiative for easily archiving and sharing trait data, which also provides a template for other nationa...