Species of the major Southern Hemisphere family, Proteaceae, have many scleromorphic anatomical structures in their leaves. Many of these structures (very thick cuticles and five anatomically distinct structures beneath the epidermis) are associated with the leaf surface exposed to direct light. These structures increase the path through which solar radiation must pass before reaching the mesophyll. In this study, such structures are proposed to protect the mesophyll from excess solar radiation, including photosynthetically active, ultraviolet, and possibly infrared radiation. Scleromorphic structures of the upper leaf surface and nonscleromorphic photoprotective structures (dense trichomes and papillae of the upper surface) occur almost exclusively in open vegetation. Open vegetation species of Proteaceae occur in oligotrophic and/or cold and/or dry places, where protection from light in excess of photosynthetic capacity and damage from ultraviolet light should be most important. Data from 123 species and a supertree constructed from available molecular phylogenies are used to show that the proposed photoprotective structures evolved many times within Proteaceae. In tests of correlated evolution, the proposed photoprotective structures are significantly associated with open vegetation, but not with dry habitats.
1. DNA metabarcoding is a cost-effective species identification approach with great potential to assist entomological ecologists. This review presents a practical guide to help entomological ecologists design their own DNA metabarcoding studies and ensure that sound ecological conclusions can be obtained.2. The review considers approaches to field sampling, laboratory work, and bioinformatic analyses, with the aim of providing the background knowledge needed to make decisions at each step of a DNA metabarcoding workflow.3. Although most conventional sampling methods can be adapted to DNA metabarcoding, this review highlights techniques that will ensure suitable DNA preservation during field sampling and laboratory storage. The review also calls for a greater understanding of the occurrence, transportation, and deposition of environmental DNA when applying DNA metabarcoding approaches for different ecosystems.4. Accurate species detection with DNA metabarcoding needs to consider biases introduced during DNA extraction and PCR amplification, cross-contamination resulting from inappropriate amplicon library preparation, and downstream bioinformatic analyses. Quantifying species abundance with DNA metabarcoding is in its infancy, yet recent studies demonstrate promise for estimating relative species abundance from DNA sequencing reads. 5. Given that bioinformatics is one of the biggest hurdles for researchers new to DNA metabarcoding, several useful graphical user interface programs are recommended for sequence data processing, and the application of emerging sequencing technologies is discussed.
The adaptive significance of the timing of the abrupt change in leaf form in Eucalyptus globulus Labill. spp. globulus was investigated using quantitative genetic analysis of several field trials containing open-pollinated progenies. Five large trials contained progeny from across the whole geographic range of this taxon. On this broad scale, early phase change appears to promote growth on two sites but not the other three, implying differential selection for the timing of phase change.
There are several methods of predicting terrestrial palaeoclimates from the size and shape of fossil leaves (foliar physiognomy). The assumptions and sources of uncertainty of these methods are considered and used to determine the true uncertainty. Their ability to predict mean annual temperature (MAT) is poor. The approximate standard errors for samples of living vegetation in North America are in the range of 1.7˚C to 2.5˚C, but the true uncertainty for fossil samples is higher. Specimens with very different physiognomy to typical specimens in the model have higher uncertainties. Besides these uncertainties, the processes of fossilisation, the allocation of specimens to taxa, and the effects of other factors on foliar physiognomy all increase the uncertainty of the predictions. Overall uncertainties in the predictions of MAT are equivalent to standard errors of about 3–5˚C depending on the nature of the fossil site and flora. Other factors affect foliar physiognomic predictions significantly because predicted MAT does not change as rapidly with altitude as true MAT, and floras from different parts of the world with similar temperatures give different temperature predictions. Mean annual temperature and one precipitation parameter (probably mean annual precipitation or the growing season precipitation) can be predicted more or less independently, although the predictions of precipitation are weak. Physiognomic signals for other climatic parameters are weak or apparently non-existent, and previously published predictions of past equability are primarily based on correlations with modern MAT, rather than physiognomy.
We introduce the AusTraits database - a compilation of measurements of plant traits for taxa in the Australian flora (hereafter AusTraits). AusTraits synthesises data on 375 traits across 29230 taxa from field campaigns, published literature, taxonomic monographs, and individual taxa descriptions. Traits vary in scope from physiological measures of performance (e.g. photosynthetic gas exchange, water-use efficiency) to morphological parameters (e.g. leaf area, seed mass, plant height) which link to aspects of ecological variation. AusTraits contains curated and harmonised individual-, species- and genus-level observations coupled to, where available, contextual information on site properties. This data descriptor provides information on version 2.1.0 of AusTraits which contains data for 937243 trait-by-taxa combinations. We envision AusTraits as an ongoing collaborative initiative for easily archiving and sharing trait data to increase our collective understanding of the Australian flora.
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