Australian Journal of Botany
Number 2 2012
Leaf morphology and leaf cuticular characters are used to reconstruct past temperatures and CO2 concentrations from leaf fossils. This relationship may be confounded by changes in water availability, but we found no evidence that either leaf form or cuticular characters of Nothofagus cunninghamii were affected by a reduction in soil water potential severe enough to strongly limit growth. Thus, fossil signals from this species are likely to be robust to major changes in water availability.
Seed rain and seed bank characteristics of shrub species in wet sclerophyll forests were measured to assess their role in population persistence. Species had varied mechanisms for reducing immaturity and senescence risk under recurrent disturbance. Dormancy, seed bank longevity and seed rain are useful syndromes for predicting species persistence.
Leaf pubescence has traditionally been considered to be related to the water economy of plants, but our results suggest that this is not the case for Cape Proteaceae. Instead we show that the primary role of pubescence is to increase reflectance, which both reduces photoinhibition and decreases leaf temperature
Plant-derived fibres and resins provide biomaterials with environmental, health and financial benefits. Triodia grasslands are dominant vegetation in the arid and semiarid regions. Localised harvesting of Triodia grasslands could have environmental benefits and provide biomaterials for desert living. Research is underway to evaluate properties of Triodia biomass and resin.
The Western Australian endemic Solanum hoplopetalum Bitter & Summerh. (Solanaceae) was identified as a potential weed risk to Australian cropping regions, including under climate change scenarios. The factors determining the distribution of the plant species were assessed using the mechanistic niche modelling program CLIMEX.
By partitioning the variance across five hierarchical levels, the oviposition pattern of a leaf-miner on Erythroxylum tortuosum plants was investigated at the spatial resolution level where the leaf traits fluctuating asymmetry and size varied the most. The importance of choosing the correct spatial scale when studying insect–plant interactions was discussed.
The anatomical and biochemical characteristics of the aborted pistils in staminate flowers of yellow horn were analysed. The pistil abortion occurs at the meiosis stage of megasporocyte cells and is related to the level of endogenous hormones (gibberellic acid and abscisic acid) and the activity of amylase isozymes in staminate flowers.
The floral biology and insect visitation of the saprophytic orchid Epipogium roseum were studied. As the bud develops, the stigma expands and contacts the pollinia to complete self-pollination, after which the flowers usually open and attract bee visitors, although bees are unable to pollinate the flowers due to the absence of a viscid disk. E. roseum evolved this obligate self-pollination strategy in the face of the uncertain pollinator services associated with its saprophytic lifestyle.
Custard-apple flower development is modelled and outputs from the model are demonstrated with respect to late 20th century warming at Alstonville, northern New South Wales, Australia. The model has applications for crop scheduling, irrespective of the direction of climate change.