Hardenbergia Violacea Research Articles

Assessing the efficacy of extruded seed pellets and microbial amendments for native revegetation

Worldwide, there is a strong need for new, innovative, large‐scale approaches to restoring diverse native vegetation. Seed‐based revegetation, while often employed, can suffer from low plant establishment. Various seed coating technologies have been widely employed for decades to promote efficient agricultural planting; however, a significant obstacle to the implementation of this technology for native species revegetation is the limited access to the expertise and techniques which are mostly confidential to and specialized for the agrochemical industry. Here we investigated whether the seeds of Australian native species may benefit from extruded pelleting, measuring both seedling emergence and early growth, and testing the pellets with and without the addition of a commercial plant probiotic. A manipulative glasshouse experiment was carried out with three treatments (bare seeded; standard pellets; pellets amended with a probiotic) for four native plant species. Incorporation of seeds within standard pellets was shown to maintain high percentages of emergence and improve growth of three of the tested species (Daviesia ulicifolia, Hardenbergia violacea, and Indigofera australis) in the glasshouse setting, with increases in mean biomass of 83, 385, and 1,002%, respectively. However, emergence in the fourth species (Bursaria spinosa) was low in all seed treatments, perhaps due to excessive sowing depth (bare seeds), while combined with being encased inside a pellet. Relative to the standard pellets, probiotic amended pellets did not impart further detectable emergence or growth benefits. Ultimately, these results highlight exciting prospects for the application of extruded seed pellets in facilitating efficient use of seed in the revegetation of some native species.

Petroleum hydrocarbon rhizoremediation and soil microbial activity improvement via cluster root formation by wild proteaceae plant species

Rhizoremediation potential of different wild plant species for total (aliphatic) petroleum hydrocarbon (TPH)-contaminated soils was investigated. Three-week-old seedlings of Acacia inaequilatera, Acacia pyrifolia, Acacia stellaticeps, Banksia seminuda, Chloris truncata, Hakea prostrata, Hardenbergia violacea, and Triodia wiseana were transplanted in a soil contaminated with diesel and engine oil as TPH at pollution levels of 4,370 (TPH1) and 7,500 (TPH2) mg kg−1, and an uncontaminated control (TPH0). After 150 days, the presence of TPH negatively affected the plant growth, but the growth inhibition effect varied between the plant species. Plant growth and associated root biomass influenced the activity of rhizo-microbiome. The presence of B. seminuda, C. truncata, and H. prostrata significantly increased the TPH removal rate (up to 30% compared to the unplanted treatment) due to the stimulation of rhizosphere microorganisms. No significant difference was observed between TPH1 and TPH2 regarding the plant tolerance and rhizoremediation potentials of the three plant species. The presence of TPH stimulated cluster root formation in B. seminuda and H. prostrata which was associated with enhanced TPH remediation of these two members of Proteaceae family. These results indicated that B. seminuda, C. truncata, and H. prostrata wild plant species could be suitable candidates for the rhizoremediation of TPH-contaminated soil.

Cryptic diversity found in Didymellaceae from Australian native legumes.

Ascochyta koolunga (Didymellaceae, Pleosporales) was first described in 2009 (as Phoma koolunga) and identified as the causal agent of Ascochyta blight of Pisum sativum (field pea) in South Australia. Since then A. koolunga has not been reported anywhere else in the world, and its origins and occurrence on other legume (Fabaceae) species remains unknown. Blight and leaf spot diseases of Australian native, pasture and naturalised legumes were studied to investigate a possible native origin of A. koolunga.Ascochyta koolunga was not detected on native, naturalised or pasture legumes that had leaf spot symptoms, in any of the studied regions in southern Australia, and only one isolate was recovered from P. sativum. However, we isolated five novel species in the Didymellaceae from leaf spots of Australian native legumes from commercial field pea regions throughout southern Australia. The novel species were classified on the basis of morphology and phylogenetic analyses of the internal transcribed spacer region and part of the RNA polymerase II subunit B gene region. Three of these species, Nothophoma garlbiwalawardasp. nov., Nothophoma naiawusp. nov. and Nothophoma ngayawangsp. nov., were isolated from Senna artemisioides. The other species described here are Epicoccum djirangnandirisp. nov. from Swainsona galegifolia and Neodidymelliopsis tinkyukukusp. nov. from Hardenbergia violacea. In addition, we report three new host-pathogen associations in Australia, namely Didymella pinodes on S. artemisioides and Vicia cracca, and D. lethalis on Lathyrus tingitanus. This is also the first report of Didymella prosopidis in Australia.

Seed provenance for changing climates: early growth traits of nonlocal seed are better adapted to future climatic scenarios, but not to current field conditions

AbstractThe urgency to repair degraded ecosystems is challenged by the need to future‐proof populations to deal with changing climates. Therefore, it is necessary to know if source gene‐pools are resilient to both current and future climatic conditions. We tested this question with the pioneer shrub Hardenbergia violacea (Fabaceae), an important species for restoration in eastern Australia. We evaluated in situ and ex situ performance of seed from eight provenances, two local and six from regions receiving hotter and wetter spring to autumn conditions and/or drier winters and we included wild and commercial collections. We compared survivorship of seedlings in climate‐houses that emulated current and predicted temperature and rainfall. In the field, we measured germination and seedling survivorship. We used neutral codominant markers to provide inbreeding and heterozygosity estimates to evaluate against health and survivorship. All provenances survived the current conditions, but local provenances were the poorest performers in the predicted hotter and wetter scenario compared with nonlocal provenances. No provenance survived more than a fortnight of a climate‐house simulated, but predicted, extreme weather event of a drought (35/22°C 12 hours day/night, 50 mL/week = 220 mm rainfall). Heterozygosity was positively associated with plant health in surviving plants, and plants in poor condition had high inbreeding estimates. In the field, nonlocal provenances performed poorly and most survivors were from local provenances. The contribution of individual genetic variation to stress tolerance will be an important consideration when selecting provenances for future climates.

Host Plants Affect the Foraging Success of Two Parasitoids that Attack Light Brown Apple Moth Epiphyas postvittana (Walker) (Lepidoptera: Tortricidae).

The light brown apple moth, Epiphyas postvittana is a key pest of wine grapes in Australia. Two parasitoids, Dolichogenidea tasmanica and Therophilus unimaculatus, attack the larval stage of this pest. D. tasmanica is dominant in vineyards, whereas T. unimaculatus is mainly active in native vegetation. We sought to understand why they differ in their use of habitats. Plants are a major component of habitats of parasitoids, and herbivore-infested plants influence parasitoid foraging efficiency by their architecture and emission of volatile chemicals. We investigated how different plant species infested by E. postvittana could affect the foraging success of the two parasitoid species in both laboratory and field experiments. Four common host-plant species were selected for this study. In paired-choice experiments to determine the innate foraging preferences for plants, both parasitoid species showed differences in innate search preferences among plant species. The plant preference of D. tasmanica was altered by oviposition experience with hosts that were feeding on other plant species. In a behavioral assay, the two parasitoid species allocated their times engaged in various types of behavior differently when foraging on different plant species. For both parasitoids, parasitism on Hardenbergia violacea was the highest of the four plant species. Significantly more larvae dropped from Myoporum insulare when attacked than from the other three host-plant species, which indicates that parasitism is also affected by interactions between plants and host insects. In vineyards, parasitism by D. tasmanica was significantly lower on M. insulare than on the other three host-plant species, but the parasitism rates were similar among the other three plant species. Our results indicate that plants play a role in the habitat preferences of these two parasitoid species by influencing their foraging behavior, and are likely to contribute to their distributions among habitats.

Transformation and plant uptake of 15N-labeled fertilizers mediated by ammonia-oxidizing bacteria in alkaline bauxite-processing residue sand amended with greenwaste compost

Ecological restoration of bauxite residue storage areas is a great challenge due to the inherently hostile characteristics (high alkalinity, high salinity and poor nutrient availability). Nitrogen (N) availability and microbial functionality are crucial indicators for successfully restoring ecosystem functions of bauxite residue storage areas. This study examined the pathway and dynamics of 15N-labeled fertilizer [e.g., ammonium sulphate (AS), potassium nitrate (KN), glycine (GL)] and the role of ammonia oxidizing archaea (AOA) and bacteria (AOB) in bauxite residue sand (BRS) amended with greenwaste compost (BRSGC) and without organic amendment (BRSNA) grown with Hardenbergia violacea and Lolium rigidum. 15N losses via volatilization and leaching from applied 15N fertilizer were higher in AS (49–50%) and GL (42–47%) compared to KN (38–44%) treatment under BRSNA. 15N losses via these pathways however, were significantly (P<0.01) reduced under BRSGC. The total residual 15N recovered in BRSGC (34–57%) was significantly higher compared with BRSNA (<2%). Uptake of applied 15N fertilizers by plants was consistently higher in BRSNA for both plants (KN>AS>GL) compared with BRSGC, suggesting an increased sorption or immobilization of applied 15N by greenwaste compost. Significant relationships observed between the AOB abundance under AS and GL treated BRS and 15N uptake by plants and extractable 15NO3–N indicated that AOB plays a significant role in the transformation of 15N and uptake by plants. These results have important implications for developing improved nutrient management strategies and ecological rehabilitation prescriptions in alkaline BRS storage areas.

Papilionoid inflorescences revisited (Leguminosae-Papilionoideae)

The inflorescence structure determines the spatiotemporal arrangement of the flowers during anthesis and is therefore vital for reproductive success. The Leguminosae are among the largest angiosperm plant families and they include some important crop plants. In papilionoid legumes, the raceme is the most common type of inflorescence. However, a range of other inflorescence types have evolved via various developmental processes. A (re-)investigation of inflorescences in Swainsona formosa, Cicer arietinum, Abrus precatorius, Hardenbergia violacea and Kennedia nigricans leads to new insights into reduction mechanisms and to a new hypothesis on the evolution of the papilionoid pseudoraceme. Inflorescence morphology and ontogeny were studied using scanning electron microscopy (SEM). The inflorescence in S. formosa is an umbel with a rare type of pendulum symmetry which may be triggered by the subtending leaf. Inflorescences in C. arietinum are reduced to a single flower. An early formed adaxial bulge is the sterile apex of the inflorescence (i.e. the inflorescence is open and not terminated by a flower). In partial inflorescences of A. precatorius, the axis is reduced and its meristem is relocated towards the main inflorescence. Flower initiation follows a peculiar pendulum pattern. Partial inflorescences in H. violacea and in K. nigricans show reduction tendencies. In both taxa, initiated but early reduced bracteoles are present. Pendulum symmetry in S. formosa is probably associated with distichous phyllotaxis. In C. arietinum, strong reduction tendencies are revealed. Based on studies of A. precatorius, the papilionoid pseudoraceme is reinterpreted as a compound raceme with condensed lateral axes. From an Abrus-like inflorescence, other types can be derived via reduction of flower number and synchronization of flower development. A plea is made for uniform usage of inflorescence terminology.

Testing the “Local Provenance” Paradigm: A Common Garden Experiment in Cumberland Plain Woodland, Sydney, Australia

AbstractSeed for restoration projects has traditionally been sourced locally to “preserve” the genetic integrity of the replanted site. Plants grown from locally sourced seeds are perceived to have the advantage of being adapted to local conditions, and the use of local provenance is a requirement of many restoration projects. However, the processes of climate change and habitat fragmentation, with the subsequent development of novel environments, are forcing us to reconsider this basic tenet of restoration ecology. We tested the “local provenance is best” paradigm, by comparing the performance of plants grown from local with non‐local seed sources within a common garden experiment. We selected six species representing a range of growth forms (Acacia falcata, Bursaria spinosa ssp. spinosa, Eucalyptus crebra, E. tereticornis, Hardenbergia violacea and Themeda australis) from an assemblage known as the Cumberland Plain Woodland, a threatened community in western Sydney. Multiple provenances were collected from within the range of each species and grown at two field sites on the Cumberland Plain. Growing time varied between species and ranged from 7 months to 2 years. With the exception of B. spinosa, and to a lesser extent T. australis, we found little evidence that local provenance plants were superior to distant provenances in terms of survival and establishment.

The discovery of microsatellite markers for Hardenbergia violacea (Fabaceae), using next-generation sequencing

Hardenbergia violacea is a climbing to prostrate shrub endemic to woodlands in the south east of Australia. We used next generation sequencing to develop a species-specific primer set. We obtained 106,529 reads in FASTA format with an average read length of 548 bp. DNA was successfully amplified for 20 markers and eight markers were characterized. The degree of polymorphism of these loci was tested on 95 samples from five populations. The total number of alleles ranged from two to 11 and observed and expected heterozygosities ranged from 0.0 to 0.807 and 0.0 to 0.933, respectively. Inbreeding coefficients were highly variable among populations, suggesting a mixture of selfing and outcrossing in nature. The characterized loci will be useful for studies of population structure, gene flow, mating systems, and the conservation and selection of provenances for restoration projects in degraded habitats.

Genetic evidence for the origins of range disjunctions in the Australian dry sclerophyll plant Hardenbergia violacea

Aim The distribution of genetic variation in the Australian dry sclerophyll plant Hardenbergia violacea (Fabaceae) is examined in the context of Pleistocene climate change in order to identify likely refugia. Particular consideration is given to the origin of range disjunctions in South Australia and Tasmania, and to determining whether the Tasmanian population is indigenous or recently introduced from mainland Australia. Location Southeastern Australian mainland and Tasmania. Methods A combination of chloroplast polymerase chain reaction–restriction fragment length polymorphism and genomic amplified fragment length polymorphism (AFLP) marker systems was used to examine the genetic structure of 292 individuals from 13 populations across the range of H. violacea in southeastern Australia. Results Hardenbergia violacea populations in Tasmania and southern Victoria were characterized by low, almost monotypic chloroplast diversity. New South Wales showed higher haplotype diversity and haplotype sharing among widely distributed populations. Principal coordinates analysis (PCoA) of the AFLP data found a strong latitudinal cline in AFLP variation from northern New South Wales south to Tasmania. The Tasmanian population formed an isolated and somewhat disjunct genetic cluster at one end of this cline. However, the South Australian population was an exception to the clinal variation shown by all other populations, forming a highly disjunct cluster in the PCoA. Within-population genetic diversity was low in both disjunct populations. Main conclusions The genetic evidence indicates that the Tasmanian population is likely to be indigenous and probably the product of vicariance, which was followed by range contraction at the Last Glacial Maximum or an earlier glacial event. The deep phylogenetic disjunction in South Australia is evidence of a much earlier separation on mainland Australia. The chloroplast structure indicates that, during the Pleistocene, H. violacea underwent broad-scale recolonization in southern Victoria and Tasmania, possibly from a large continental refugium in eastern New South Wales. We conclude that H. violacea, and presumably the sclerophyll communities in which it occurs, have undergone multiple range contractions to large continental refugia during different Pleistocene glaciations in southeastern Australia.

Floral ontogeny of Hardenbergia violacea (Fabaceae: Faboideae: Phaseoleae) and taxa of tribes Bossiaeeae and Mirbelieae, with emphasis on presence of pseudoraceme inflorescences

The floral ontogeny of several Australian papilionoid taxa has been studied in Hardenbergia violacea L. (Phaseoleae); Kennedia rubicunda (Phaseoleae; inflorescences only); Bossiaea cordigera (Bossiaeeae); Gastrolobium truncatum, Mirbelia oxylobioides, and Pultenaea daphnoides (Mirbelieae). Species studied of Hardenbergia, Pultenaea, and Brachysema have pseudoracemose inflorescences comprised of triads of flowers, Kennedia rubicunda has paired flowers that resemble reduced pseudoracemes, while Gastrolobium truncatum and Mirbelia oxylobioides have pseudoracemes comprised of 2–10 flowers per ultimate unit. Pseudoracemes are a significant and overlooked feature in many taxa of tribes Bossiaeeae and Mirbelieae. Hardenbergia violacea has ultimate axillary units of three flowers, each with a subtending bract but no bracteoles. Floral ontogeny in H. violacea and P. daphnoides shows acropetal order among whorls, and unidirectional order starting from the abaxial side in sepal, petal, and stamen whorls, as in most papilionoid flowers. The carpel is initiated concurrently with the first antesepalous stamen primordium. Pultenaea daphnoides and Bossiaea cordigera have unidirectional sepal initiation starting abaxially, but simultaneous petal initiation, an unusual feature among papilionoids. In late stages of H. violacea and B. cordigera, a diadelphous stamen tube or sheath is formed, while in taxa of Mirbelieae the stamens remain free. The flowers in all taxa studied become strongly zygomorphic as evidenced by three petal morphs and upturning of the free portions of style and stamens late in development.

Dual Control of Flower Initiation and Development by Temperature and Photoperiod in Hardenbergia violacea

Exposure to both short-day photoperiods (&lt; 12.5 h daily) and cool temperatures (15–18°C) is optimal for inflorescence initiation and development in the woody perennial Hardenbergia violacea (Scheeve) Stearn, an Australian leguminous plant species. After 9–12 weeks exposure to inductive conditions the inflorescences were 1–2 cm long and floral organ primordia were evident. At this stage of development, transferring plants to warmer conditions (e.g. 22°C) and/or long days led to flower bud abortion, abscission of the inflorescence and a resumption of vegetative growth within 30 days. Conversely, flowers opened with continued exposure to short days. Flower initiation and development of this Hardenbergia selection (cultivar Mini haha) is thus restricted to a narrow temperature range (15–18°C) in combination with a requirement for exposure to short days. Such complexity must be important in adaptation of Hardenbergia to its environment.

An Antimicrobial Peptide from the Australian Native Hardenbergia violacea Provides the First Functionally Characterised Member of a Subfamily of Plant Defensins

An antimicrobial peptide (HvAMP1) was isolated from seeds of the Australian native legume Hardenbergia violacea (Schneev.) Stearn. The peptide is 47 amino acid residues in length, contains 8 cysteines, and has a molecular weight of 5392 and a predicted pI of 10.41. HvAMP1 inhibited the growth of several plant pathogenic fungi at concentrations as low as 1 µM in vitro and produced distinct hyphal distortion and increased branching. This antimicrobial activity was greatly diminished in the presence of 1 mM CaCl2 and 50 mM KCl. The purified peptide at 40 µM did not inhibit three different a-amylase enzymes. Aeukaryotic cell-free translation system showed inhibition approaching 50% in the presence of ~100 µM of HvAMP1. The viability of plant and mammalian cells cultured in vitro was not adversely affected by concentrations of HvAMP1 as high as 40 mM. The amino acid sequence of HvAMP1 contained the consensus amino acids that define the plant defensin family of peptides. The HvAMP1 amino acid sequence showed 87% and 57% identity with the amino acid sequences deduced from cDNA sequences from defensins of Vigna unguiculata and Pisum sativum, respectively. Other plant defensin sequences showed less than 33% amino acid identity to the peptide. Therefore, HvAMP1 and the putative plant defensins of cowpea and pea define a distinct sequence subfamily of plant defensins which is at present limited to members of the Fabaceae. HvAMP1 is the first member of this subfamily to be purified and functionally characterised. The antimicrobial activity of HvAMP1 suggests a defensive role for this subfamily of peptides.

Hardenbergia violacea (Fabaceae), is it native in Tasmania?

Hardenbergia violacea (Schneev) Stearn is accepted as native in Tasmania. Hardenbergia violaceawas first described (as Glycine violacea) by Schneevoogt (l 793) from cultivated planes probably collected as seeds in the Sydney area in the first few years of settlement. This scrambling or trailing perennial grows from a woody rootstock and produces long wiry stems that climb on ocher planes or trail over rocky outcrops. le is well known in Victoria and New South Wales, where it occurs widely in dry open forests, but its occurrence in Tasmania is limited to the Pomos Hills near Richmond in the southeastern part of the state.

Seasonal frost tolerance of some ornamental evergreen broad-leaved and coniferous tree and shrub species

Abstract The seasonal frost hardiness of several ornamental species was evaluated by exposing intact plants to controlled advective frost conditions in spring, midsummer, autumn, and midwinter. Cultivars of the evergreen broad-leaved species Camellia japonica, Daphne odora, Desfontainea spinosa, Grevillea × gaudi-chaudi, Hardenbergia violacea, Hypericum × moserianum, Nandina domestica, and Photinia serrulata × glabra ‘Rubens’ all developed limited winter frost hardiness with the most hardy (Camellia and Photinia) being killed at temperatures below-17°C. Generally, evergreen broad-leaved species from northern zones were more tolerant than Australasian species. Of the ornamental conifers examined, Cupressus macrocarpa was only moderately hardy in winter, being injured by temperatures lower than-8°C and killed below-14°C, whereas Juniperus chinensis tolerated temperatures down to-19°C without injury. The summer frost tolerance of all of these species was similar and all were injured or killed by temperatures in the-1 to-5°C range. Yucca filamentosa, a species with a xerophytic morphology, was damaged at-13°C but survived-17°C in summer and was not injured by winter temperatures down to-17°C. Lethal temperature values obtained in the controlled environment evaluations generally agreed well with hardiness zone ratings.

GROWTH AND NUTRIENT ACCUMULATION BY FRUITS OF THE PERENNIAL LEGUME, HARDENBERGIA VIOL ACE A, WITH SPECIAL REFERENCE TO MYRMECOCHORY.

The growth and mineral nutrition of developing fruits of the perennial Australian legume Hardenbergia violacea (Schneev.) Steam (Fabaceae) was studied using plants from a natural habitat near Rankins Springs, central-western New South Wales, Australia. The accumulation and partitioning of dry matter and 12 mineral nutrients in pods and seeds of fruits is described. Seeds accumulated about 50% of the dry matter of a mature fruit, over 90% of its N and P content, 50 to 75% of its K, Ca, Mn, Cl, S, Zn, Cu and Mg, but less than 50% of its Fe and Na. Over 75 % of the N and P content of pods was redistributed during senescence, although other nutrients and dry matter were not redistributed to the same extent; there was negligible redistribution of Ca, Cl, Na, Fe and Mn from the pod. Redistribution of N and P from the pod could have provided up to 30% of these nutrients accumulated by mature seeds. Concentrations of most nutrients were higher in seeds than pods. The testa made up 60% of the dry matter content of a seed and contained the major proportion of its Ca, Mg, Cl, Na and Mn; the embryo contained most of the seed's contents of N, P, K, S, Zn and Cu. The elaiosomes had less than 5% of the seed's dry matter and mineral nutrient content. The oil content of the elaiosome was 34%, compared to 12% for the embryo. Oleic acid made up over 60% of the fatty acid content of elaiosome oil. Aspartic acid, arginine and glycine were the major amino acids in the elaiosome. The embryo contained 10% of the non-protein anti-metabolic amino acid, canavanine, the elaiosome only 1%. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis showed that the subunit protein compositions of the elaiosome and embryo were different. The composition of the elaiosome is discussed in relation to the nutrition of ants. It is concluded that, in H. violacea, the elaiosome represents a nutritionally cheap means to the plant of achieving secondary seed dispersal by ants.

The chemical composition of seeds from some Australian plants

The seeds from 18 Australian native plants were evaluated for their potential as food crops by assessing their nutritive values. Proximate analyses for water, protein and oil content were conducted, together with detailed analyses of the fatty acid content of the triglycerides, and of the amino acid content. Four plants, Hovea elliptica, Hardenbergia violacea, Crotalaria cunninghamii and Kennedia nigricans, were found to have a chemical composition which may have the potential for human food.