Australian Journal of Botany

Australian Journal of Botany is an international journal for the publication of original research and reviews in plant science with relevance to Southern Hemisphere ecosystems including ecology and ecophysiology, conservation biology and biodiversity, forest biology and management, cell and molecular biology, palaeobotany, reproductive biology and genetics, mycology and pathology and structure and development. Read more about the journalMore

Editor-in-Chief: Dick Williams

Current Issue

Australian Journal of Botany

Volume 65 Number 3 2017

BT16147Gleditsia triacanthos (Fabaceae) in Argentina: a review of its invasion

Romina D. Fernandez, Sergio J. Ceballos, Agustina Malizia and Roxana Aragón

pp. 203-213

Gleditsia triacanthos is a woody exotic species that colonises different ecosystems in several countries around the world. In this work we review numerous studies about its invasion to show its importance as an invasive species in Argentina. Since the end of the 18th century, G. triacanthos has spread across different ecoregions in Argentina affecting flora, fauna and ecosystem processes. Our review highlights the need to develop monitoring and control strategies for this invasive species.

BT16179Causes and consequences of variation in snow incidence on the high mountains of Tasmania, 1983–2013

Jamie B. Kirkpatrick, Manuel Nunez, Kerry L. Bridle, Jared Parry and Neil Gibson

pp. 214-224

The incidence of snow was largely constant between 1983 and 2013 at Mt Field and on other high mountains in Tasmania, but decreased on lower elevation alpine mountains, trends apparently caused by changes in atmospheric instability. At Mt Field, obligate snow patch species persisted during the same period and cushion plants and shrubs increased.

BT16253Evidence of reward production and pollination by Centris in Encyclia (Orchidaceae: Laeliinae): the reproductive biology of Encyclia mapuerae

A. H. Krahl, D. R. P. Krahl, J. J. Valsko, A. C. Webber and E. R. Pansarin

pp. 225-232

In this paper we report on studies of the reproduction biology of an Amazonian orchid pollinated by Centridini bees that search for nectar on flowers. To our knowledge, this is the first report of reward production in Encyclia. This discovery provides new insights on the function of the cuniculus in Laeliinae, and sheds light on the evolution of floral rewards and pollination mechanisms within this diverse group of Neotropical orchids.

BT16238Pollen development and orbicule and pollen grain morphology in species of Cephalanthus (Rubiaceae-Naucleeae) from the Americas

María Florencia Romero, Roberto Salas and Ana Maria Gonzalez

pp. 233-247

This study is the first embryological report on male structures in the genus Cephalanthus. It includes the analysis of anther development, both the study of the processes leading to the formation of pollen and the histology of the wall of the anther, describing how dehiscence occurs. The results contribute to future studies in other genera of the tribe Naucleeae in the Rubiaceae family.

BT16244Are we underestimating the impact of rising summer temperatures on dormancy loss in hard-seeded species?

Anne Cochrane

pp. 248-256

Physical dormancy prevents immediate germination of seed and allows species to maintain a persistent soil seed bank providing the resource for post-fire recovery of plant populations. Temperature is a key driver for dormancy release but hot summer temperatures can result in rupture of the seed coat in the inter-fire period. Gradual leakage of seed from the seed bank under a warming climate may compromise the risk-spreading ability afforded by hardseededness potentially reducing species capacity to recover from disturbance.

BT16183Intraspecific diversity of terpenes of Eucalyptus camaldulensis (Myrtaceae) at a continental scale

Carlos Bustos-Segura, Shannon Dillon, Andras Keszei, William J. Foley and Carsten Külheim

pp. 257-269

Eucalyptus camaldulensis is the most widely distributed Eucalyptus species both globally and in its native range. In the present study, we explored the natural variation in foliar terpene composition across its natural distribution in Australia and how elevated CO₂ can affect the accumulation of terpenes. We found four chemical varieties dominated by different monoterpenes across the natural range. In addition, plants growing under elevated CO₂ accumulated a lower concentration of monoterpenes, suggesting that climate change can affect terpene accumulation in natural populations and plantations.

BT16216Demographic, dispersal, predation and genetic data reveal the potential vulnerability of an endangered rainforest shrub, Triunia robusta (Proteaceae)

Yoko Shimizu-Kimura, Scott Burnett and Alison Shapcott

pp. 270-282

We investigated the demographic, dispersal and predation dynamics of an endangered rainforest shrub, Triunia robusta (Proteaceae). A life cohort table was developed from field demographic data, the potential dispersal distance was assessed and the effects of predation on seed and seedling mortality were quantified. It was found that T. robusta has limited dispersal, high post-predation mortality rates and relatively low reproductive rates, suggesting that critically small and isolated populations may be highly vulnerable.

BT17025Germination ecology of the endangered species Asterolasia buxifolia (Rutaceae): smoke response depends on season and light

Justin C. Collette and Mark K. J. Ooi

pp. 283-291

Germination of fire-prone plant species can be complex. Understanding this key component of the regeneration niche can help elucidate mechanisms for persistence and inform conservation. Like many threatened species in fire-prone south-eastern Australia, Asterolasia buxifolia is restricted to riparian habitats. Germination ecology of this physiologically dormant family (Rutaceae) is not well understood. We found that seeds germinated only with smoke at winter temperatures. Darkness inhibited germination. These results help us understand why such species may be limited to riparian habitat.

BT16220Xylem vessel length and distribution: does analysis method matter? A study using Acacia

Virginia G. Williamson and John A. Milburn

pp. 292-303

Measuring xylem conduit length and distribution is important but tedious, and so it is often avoided. For decades, several measurement techniques have been debated, so we compared four classic methods and found none to be significantly different; however, we recommend the Christman method because it ensures ease of calculation. Accurate calculation of conduit length is crucial for many reasons, including comparison of global datasets on the potential plasticity of xylem characteristics, which is important information in a changing climate.

Online Early

The peer-reviewed and edited version of record published online before inclusion in an issue

Published online 22 June 2017

BT16232High outcrossing rates and short-distance pollination in a species restricted to granitic inselbergs

Karina Vanessa Hmeljevski, Marina Wolowski, Rafaela Campostrini Forzza and Leandro Freitas

Encholirium horridum is a species of bromeliad – the same family of plants as the pineapple – that only occurs on some isolated granitic outcrops in Brazil. Its flowers are mainly pollinated by bats and hummingbirds. And although these animals can fly over a long distance, pollen movement among flowers was concentrated in the neighbourhood. This affects seed viability and outcrossing rates of this endangered plant.

Published online 22 June 2017

BT16189Metal uptake and organic acid exudation of native Acacia species in mine tailings

Sebla Kabas, Felipe Saavedra-Mella, Trang Huynh, Peter M. Kopittke, Steve Carter and Longbin Huang

Metal mine tailings have emerged as a global environmental threat and require urgent rehabilitation with sustainable native plant communities. Native Acacia species as keystone species in semiarid regions of Australia exhibited different root exudation capability and associated metal uptake. As a result, those Acacia species taking up low levels of metals may be selected for the initial rapid phytostabilisation of metal mine tailings.

Published online 06 June 2017

BT17014Inhibitory action of allelochemicals from Artemisia nanschanica to control Pedicularis kansuensis, an annual weed of alpine grasslands

Zhanhuan Shang, Yuan Hou, Fei Li, Cancan Guo, Tianhua Jia, A. Allan Degen, Andrew White, Luming Ding and Ruijun Long

Allelochemicals can be used for biological weed management and can minimise environmental impacts related to herbicides. The aim of the present study was to identify allelochemicals of Artemisia nanschanica, a weed with strong allelopathic effects, that could potentially control Pedicularis kansuensis, a weed that causes rapid degradation of alpine pastures. Three allelochemicals were identified that can be used to biologically control P. kansuensis.