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Preview: Australian Journal of Botany

Australian Journal of Botany

Recent research papers from the Australian Journal of Botany


Wood anatomy of Australian mirbelioids and allies (Fabaceae, Papilionoideae)


A. V. Stepanova, A. A. Oskolski, B.-E. Van Wyk

The evolutionary significance of wood anatomical characters of the Australian legume tribes Bossiaeeae and Mirbelieae is explored for the first time. Short vessel elements and the unique presence of tanniniferous tubes support the idea of a relationship with the South African tribe Hypocalypteae. The results highlight another interesting connection between the Australian and South African floras.

Can the mother plant age of Acacia melanoxylon (Leguminosae) modulate the germinative response to fire?


Oscar Cruz, Juan García-Duro, Mercedes Casal, Otilia Reyes

To control or to favour populations of Acacia melanoxylon it is necessary to know its germinative strategy. Our work shows that fire can greatly affect the amount of seeds of A. melanoxylon germinated and that the age of mother plants influences the time in which the germination occurs after fire. These results have important implications for the management of this species whatever its purpose – either the implementation of control measures or ecological restoration.

Priorities for enhancing the ex situ conservation and use of Australian crop wild relatives


Sally L. Norton, Colin K. Khoury, Chrystian C. Sosa, Nora P. Castañeda-Álvarez, Harold A. Achicanoy, Steven Sotelo

Contributions by Australia’s crop wild relatives to plant breeding are dependent upon their availability for research via genebanks, yet the comprehensiveness of genebank collections for these species has not been assessed. We determined the state of representation of Australia’s major food crop wild relatives in ex situ conservation, identifying the gaps needing to be filled and outlining the key activities required to more fully safeguard their diversity and to increase their use.

Insect herbivory on snow gum (Eucalyptus pauciflora, Myrtaceae) saplings near the alpine treeline: the influence of local- and landscape-scale processes


Citra D. Dashiell, Shannon LeBel, Peter T. Green, Susanna E. Venn, John W. Morgan

Ecological interactions between plants and insect herbivores in Australian high mountains remain largely unexplored. We quantify the effects of herbivores on snow gum saplings near the alpine treeline and show that leaf loss is a function of elevation, plant height and traits such as leaf thickness.

Nutritional and physiological responses of the dicotyledonous halophyte Sarcocornia fruticosa to salinity


Pedro García-Caparrós, Alfonso Llanderal, Maribela Pestana, Pedro José Correia, María Teresa Lao

Plants of Sarcocornia fruticosa were subjected to five saline treatments (10 (control), 60, 100, 200 and 300 mM NaCl) over a period of 60 days. The results of this experiment showed that S. fruticosa can maintain its major physiological processes at 60 mM NaCl without significant dry weight reduction.

Anatomy and function of the root system of bromeliad Nidularium minutum


José L. Carvalho, Adriana H. Hayashi, Shoey Kanashiro, Armando R. Tavares

The anatomical study of the bromeliad Nidularium minutum Mez roots showed the occurrence of a multiseriate epidermis, termed velamen. The root system was as efficient as the tank for nutrients uptake, contributing to plant growth and development, most likely assisted by the presence of velamen.

Seed viability of early maturing alpine ash (Eucalyptus delegatensis subsp. delegatensis) in the Australian Alps, south-eastern Australia, and its implications for management under changing fire regimes


Michael D. Doherty, A. Malcolm Gill, Geoffrey J. Cary, Mike P. Austin

Eucalyptus delegatensis R.T. Baker subsp. delegatensis is an interval-sensitive, fire-killed eucalypt found in the Australian Alps. Flowering and fruiting in stands of saplings regenerating after the 2003 fires is occurring much earlier than previously thought. Seed from such early maturing alpine is viable, with a mean of 455 (s.d. = 139) germinants per 10 g of chaff and seed mix.

Morphoanatomical characteristics of leaves of Anacardium othonianum seedlings subjected to different nitrogen doses under hydroponic conditions


Layara A. Bessa, Marialva A. Moreira, Fabiano G. Silva, Luciana C. Vitorino, Cássia L. Rodrigues, Sebastião C. V. Filho

Nitrogen is an essential nutrient for plant metabolic processes, so nutritional conditions can affect leaves and plant survival. A study of the effects of N on the foliar morphoanatomy of Anacardium othonianum showed that absence and excess of this nutrient affect leaf structure, as well as the synthesis of compounds of the metabolism. This work contributes to biological knowledge this species and to the growth of healthier seedlings.

Flower development in species of Croton (Euphorbiaceae) and its implications for floral morphological diversity in the genus


Karina Bertechine Gagliardi, Inês Cordeiro, Diego Demarco

Flowers and inflorescences are extremely diverse and some of them show structures that are difficult to interpret, which led us to ask: how are these flowers built? Inside the family of castor beans, Euphorbiaceae, a large group, Croton, shows small flowers containing some structures that are alternatively considered as petals, glands or simple filaments. Studying the development of these flowers reveals the origin of the floral parts and their real identity, taking us closer to decipher flower diversity.’

Effects of selective thinning and residue removal on ground layer structure and diversity in a mixed pine–oak stand of the Qinling Mountains, China


Lin Hou, Shan Sun, Liyan Liang, Ge Liang, Luxi Jiang

Understorey is a key component of a forest ecosystem. Forest thinning may change the structure, diversity and cover of the understorey by reducing tree density and increasing gaps in the forest canopy. To achieve the highest richness, evenness and cover, a combination of selective thinning intensity and residue removal rate were suggested by applying a central composite design.

The importance of travelling stock reserves for maintaining high-quality threatened temperate woodlands


Thea O'Loughlin, Luke S. O'Loughlin, Damian R. Michael, Jeffrey T. Wood, Helen P. Waudby, Phillip Falcke, David B. Lindenmayer

Travelling stock reserves (TSRs) are critically important for the conservation of temperate woodland communities that have otherwise been extensively cleared and degraded for agriculture. We compared the vegetation attributes of TSRs with remnants managed for agricultural production and found the former supported higher native plant species richness, more native ground cover and fewer exotic plants. Our results indicate that land tenure status of remnant woodlands generally influenced several vegetation attributes that are also important for native biodiversity.

Pollinarium size as a hybridisation barrier between sympatric inter-compatible orchids


B. C. Vieira, L. M. Pansarin, M. E. P. Martucci, L. Gobbo-Neto, E. R. Pansarin

This work reports on the occurrence of natural hybridisation between three sympatric orchid species. The reproduction of the species was recorded based on morpho-anatomical, histochemical analyses and intra- and interspecific crosses. The relationship between co-occurring species was verified by floral morphometry and principal component analysis, and sequence divergence analyses. All data collected suggest that no gene flow is currently occurring, and that hybridisation has been avoided due to the incompatible pollinarium size between the sympatric species, which acts as a pre-mating barrier in the studied population.

Seed dormancy and germination of three grassy woodland forbs required for diverse restoration


Gabrielle S. Vening, Lydia K. Guja, Peter G. Spooner, Jodi N. Price

Restoration is vital for the re-establishment of degraded communities, but success is often hindered by issues related to seed biology. We examined dormancy-alleviation and germination-promotion techniques for three common grassy woodland forbs required for diverse restoration. Scarification of the seed produced the highest germination for Dianella longifolia and Stackhousia monogyna, whereas germination of Dianella revoluta requires further examination. This information can advance methods to propagate these species from seed and contribute to greater understorey diversity in grassy woodland restoration.

Regarding the structure and possible function of the columella in seed cones of Callitroideae (Cupressaceae): a morpho-anatomical approach


Veit Martin Dörken, Armin Jagel - Volume 65(5)

Several callitroid Cupressaceae have a column-like structure – termed ‘columella’ – that are developed distally in the seed cones, which exclusively represents the prolonged tip of the cone axis. Thus, the distal three-part structure of Fitzroya represents a sterile whorl of cone scales that should not be termed columella. It is suggested that columellae that exceed the ovules, play a role in the pollination process, whereas prolonged, resinous columellae play a role in the chemical defence against pathogens.

Nickel effect on root-meristem cell division in Plantago lanceolata (Plantaginaceae) seedlings


Dolja Pavlova - Volume 65(5)

Plantago lanceolata is a variable species growing on different soils but is not abundant on serpentines. Nickel effect on root-cell division is the reason for the low percentage of divided cells, high percentage of abnormalities, and variation of karyotype morphology. Unsuccessful distribution of the species on serpentine soils is related to its poor adaptation to stress conditions provided by the elevated metal concentrations in the soils.

Adaptive strategy of tree communities on an environmental harshness hinterland inselberg in Minas Gerais, Brazil


Felipe de Carvalho Araujo, Carolina Njaime Mendes, Gabriela Gomes Pires, Gisele Cristina de Oliveira Menino, Marco Aurelio Leite Fontes, Rubens Manoel Dos Santos - Volume 65(5)

Our research tested the hypotheses that environmental harshness enhances sprouting, a trait displayed by trees as an adaptive strategy to habitat persistence. Over the 5 years of the study, sprouting proved to be a strategy of persistence. Multi-stemmed trees have different dynamics compared to single-stemmed trees. Factors such as soil depth, may be the cause of sprouting in trees.

Aeluropus littoralis maintains adequate gas exchange, pigment composition and phenolic contents under combined effects of salinity and phosphorus deficiency


Ons Talbi Zribi, Kamel Hessini, Najla Trabelsi, Fethia Zribi, Abdelwahed Hamdi, Riadh Ksouri, Chedly Abdelly - Volume 65(5)

The ability of Aeluropus littoralis to cope with both phosphorus (P) deficiency and high salt stresses is a result of several mechanisms mainly involved in the conservation of the integrity of the photosynthetic apparatus. Secondary metabolites – mainly phenolic compounds and carotenoids – play an important role in the protection of A. littoralis plants against oxidative damage under combined high salinity and P deficiency stresses.

Relationship between nitrogen resorption and leaf size in the aroid vine Rhodospatha oblongata (Araceae)


André Mantovani, Dulce Mantuano, Eduardo Arcoverde de Mattos - Volume 65(5)

Although leaves of Rhodospatha oblongata increased 35 times in area and 50% in vein density, the N concentration was always around 2–3% in green leaves and 1–2% in senescent leaves. Consequently, increase in vein density or in the amount of leaf N content were not the main constraining factors to leaf nitrogen resorption.

Influence of auxin and phenolic accumulation on the patterns of cell differentiation in distinct gall morphotypes on Piptadenia gonoacantha (Fabaceae)


Cibele Souza Bedetti, Gracielle Pereira Bragança, Rosy Mary dos Santos Isaias - Volume 65(5)

The accumulation of IAA–phenolics was compartmentalised on the basis of gall morphotypes on Piptadenia gonoacantha. The sites of accumulation coincided with the most hypertrophied regions, i.e., the cells of superior and lateral inferior cortices in the lenticular galls, and throughout the outer cortex in the globoid galls, which influenced on the determination of the lenticular and globoid shapes.

Going nowhere fast: a review of seed dispersal in eucalypts


Trevor H. Booth - Volume 65(5)

This paper considers how far natural stands of eucalypt species are likely to be able to disperse in the period to 2085. Although rare long-distance events cannot be ruled out, the most likely dispersal distances are about 70–140 m. However, limitations such as inadequate remnant stands and extensive agricultural developments may reduce actual migration rates below even this modest potential.

Reproductive size thresholds and seedling survival in Acacia harpophylla (Mimosaceae)


John M. Dwyer - Volume 65(5)

The capacity of Acacia harpophylla (brigalow) to resprout on cleared land is well documented, but its ability to recruit new individuals sexually is poorly understood because such reproduction events are rare. This study, undertaken following widespread flowering in late 2007, recorded very high initial densities of germinated seedlings (46 000 seedlings ha–1 on average), but less than 1% were estimated to survive the first year. Given the dramatic over-clearing of brigalow, such ecological knowledge is crucial for managing remaining populations.

Thermogenesis and developmental progression of Macrozamia macleayi pollen cones


R. B. Roemer, D. Booth, L. I. Terry, G. H. Walter - Volume 65(5)

The thermal activity of Macrozamia macleayi Miq. (family Zamiaceae) pollen cones changes with developmental stage in a manner similar to Cycas micronesica K.D. Hill (family Cycadaceae) pollen cones, suggesting a conserved physiological response across cycad families. The Macrozamia macleayi cones use carbohydrates, but not lipids, to fuel their large dehiscence stage thermogenic events, during which evaporation rates increase considerably.

A comparison of xylem vessel metrics between tropical and temperate Rhododendron species across elevation ranges


Tatpong Tulyananda, Erik T. Nilsen - Volume 65(4)

Temperate species of Rhododendron are protected from freezing induced embolisms by narrow vessels and have low efficiency for water flow, which is maladaptive for tropical species. We discovered that tropical Rhododendron species marginally relax protection against freeze–thaw and increase water flow capability. The trade-off between safety and efficiency in plants is supported, but change is limited within this single genus.

Floral morphology of Eucalyptus leucoxylon (Myrtaceae) facilitates pollination by lorikeet (Aves: Psittacidae) tongues


Joseph P. Zilko, Susan E. Hoebee, Trevor J. Edwards - Volume 65(4)

Lorikeets feed on large numbers of Eucalyptus flowers and supposedly pollinate some species, yet floral traits that facilitate this type of pollination have never been examined. Flowers of some species release pollen before the filaments unfurl, potentially excluding insects and allowing lorikeets to lick pollen with their tongues, which is then carried in large numbers to other flowers. These morphological and developmental traits facilitate considerable pollinator specificity.

Liana and bamboo cover threaten shrub populations in Atlantic forest fragments


Magda Silva Carneiro, Caroline Cambraia Furtado Campos, Flavio Nunes Ramos - Volume 65(4)

Forest fragmentation is a major threat to tropical biodiversity. We investigated how biotic and abiotic factors affect total abundance and the numbers of individuals at each life stage of Psychotria vellosiana Benth. Our results indicate that forest fragmentation has led to alterations in the structure and abundance of this species, as all of its life stages are adversely affected by liana and bamboo cover.