Browsing by Browse by SEO 2008 "820209 Ornamentals, Natives, Flowers and Nursery Plants"

In vitro bud and shoot organogenesis was investigated for the ornamental plants Eucalyptus erythronema var. erythronema, E. stricklandii and their interspecific hybrids cv. 'Urrbrae Gem' and 'Hybrid 2.5' by using 0.0, 0.1, 0.25, 0.5 or 1.0 mM BAP on apex and leaf explants. Callus developed on all explants and increased with all concentrations of BAP without significant differences between BAP concentrations. Buds formed on apex and leaf explants of E. erythronema and E. cv. 'Urrbrae Gem' especially with 1.0 mM BAP, but these buds rarely developed into shoots. Bud clusters formed on E. erythronema and E. cv. 'Urrbrae Gem' apex and leaf explants whereas E. stricklandii and 'Hybrid 2.5' produced fewer, individual buds on the explant. Shoots regenerated from apex explants of all genotypes with all levels of BAP, whereas few shoots of any genotype regenerated from leaf explants regardless of the number of buds formed. Shoots from apex explants could be multiplied successfully. Light microscopy showed meristems developed within the callus, and at the callus and bud surfaces. However, few shoots developed considering the level of bud and meristem formation. This report is the first for successful shoot organogenesis and multiplication in an ornamental eucalypt.

'Banksia' species (Plate I) have been cultivated for the international cut flower market for only 20 to 30 years, but there is increasing interest in areas other than the native home, Australia, with production in Israel, South Africa, Hawaii, and California (Ben-Jaacov 1986; Sedgley 1996). Within Australia, 'Banksia' is one of the four most widely planted commercial native genera, but production is based on seedling material and between plant variability is high. 'Banksia' species for the fresh cut flower market must fulfill strict commercial criteria, which include terminal blooms and long stem length (Fig. 1.1), and further research is needed into all aspects of 'Banksia' biology and production. In addition to the fresh cut flower market, 'Banksia' stems are traded as dried and dyed blooms, and a wide range of species is used in environmental horticulture, for the attractive inflorescences and foliage, and to attract birds and other wildlife. Although there has been little work conducted so far on the use of banksias as pot plants, recent developments with related genera suggest that such an approach may be productive (Ben-Jaacov et al. 1989). 'Banksia' wood and cones are turned or incorporated into ornaments, and the timber of some species has been used for furniture.

What the report is about: The aim of this study was to determine the pollen donors for five olive major cultivars, using paternity analysis. Bloom time, pollen vitality, and weather conditions during the flowering period were also recorded. The study was done over two years at two sites and different compatibilities between cultivars were identified. Who is the report targeted at: The olive industry will benefit from the results of this project through potential increases in productivity. Many orchards have been established without due regard to the requirements of cross-pollination. The results from this project will provide valuable guidelines to anyone planning new plantings. In addition, they can be used to increase productivity in established groves through the addition of new pollen donors. The effect of introducing compatible pollen donors to a mono-varietal grove could improve yield (fruit set) from less than 1% up to 4%. New trees can be introduced through grafting onto old trees or inter-planting. This research also has environmental benefits as a significant increase in yields could be achieved without expansion of land use, irrigation or addition of fertilisers or chemicals for pest and disease control.

Organogenesis and somatic embryogenesis were investigated in apex and cotyledon explants of 'Eucalyptus erythronema, E. strick landii' and their inter-specific hybrids 'Eucalyptus erythronema' X E. 'stricklandii cv'. 'Urrbrae Gem' and 'Hybrid 2.5', following exposure to 1 mg 1-¹ naphthaleneacetic acid (NAA) plus 1 mg 1-¹ 2,4dichlorophenoxyacetic acid (2,4-0), or 3, 5 or 15 mg 1-¹ NAA alone. Somatic embryogenesis was not observed macroscopically; however, structures characteristic of globular somatic embryos or root primordia were observed using light microscopy of apex explants of 'Urrbrae Gem' seedlings after 14 d on Murashige and Skoog (1962) (MS) medium supplemented with 3 mg 1-¹ NAA. Root development was associated with explant vascular tissue and observed in all plant growth regulator (PGR) treatments, but was less on explants treated with 1 mg 1-¹ NAA plus 1 mg 1-¹ 2,4-0 than in all NAA-alone treatments. Shoot development was observed on apex explants after sub-culture on PGR-free medium, but was less after treatment with 1 mg 1-¹ NAA plus 1 mg 1-¹ 2,4-0 compared to all NAA-on1y treatments. Roots and sho ts developed simultaneously on apex explants after culture for 1 week on MS medium supplemented with 15 mg 1-¹NAA.

'Swainsona formos'a (G.Don) J.Thompson (Sturt's desert pea) is used in commercial floriculture for cut flowers and ornamental pot plants; however, accurate identification of the growth stages is critically important in making management decisions in floricultural crops. This plant was investigated by stereomicroscopy and scanning electron microscopy (SEM) to identify flowering time and stages of floral development. This is the first work to describe the complete floral ontogeny in a member of tribe Galegeae. Conversion from vegetative to reproductive stages began within 40–46 days after seed germination for axillary branches and within 46–52 days for central stems. Plants required 807.5 days °C growing degree-days for axillary branches and 921.5 days °C for central stems to reach 50% flowering. The central stem grew more nodes (11.1±0.97 nodes) before the initiation of the first flower than did the axillary branches (7.2±0.93 nodes). The order of floral organ initiation within each whorl is unidirectional, except for the petal whorl, which is simultaneous; the flower is organised into five whorls and shows a pentamerous arrangement of sepals and petals, 10 stamens in two whorls and a central carpel.

The hypothesis that plants of the ornamental Australian native legume 'Swainsona formosa' (Sturt's desert pea) with reduced flower pigmentation are more susceptible to soilborne diseases was investigated using red, pink and white-flowered lines challenged with 'Phytophthora cinnamomi'. Inoculations of roots, hypocotyls and detached stems showed that the red line was completely resistant, the white line highly susceptible, and the pink line intermediate in reaction. Similar results were obtained for root and detached stem assays using 'Pythium' irregulare and 'Fusarium solani' isolated from diseased white-flowered plants, but all lines were equally susceptible to Botrytis 'cinerea' in detached stem assays. Crosses between the red and white lines showed that white flowers and susceptibility to 'P. cinnamomi' were each determined by recessive alleles at single loci, which segregated together.

Sturt's desert pea ('Swainsona formosa') is an Australian native legume used as an ornamental pot plant and is also suitable for hanging baskets and as a cut flower. One of the impediments to the commercialisation of S. 'formosa' as a pot plant is its inability to produce flower under low light conditions. The work reported here investigated the effect of high light intensity (800 ± 50 μmol m⁻²s⁻¹) and low light intensity (150 ± 10 μmol m⁻²s⁻¹) on the flowering of 'S. formosa' with particular emphasis on the changes of glucose concentration in shoot apices from the vegetative to floral stages. Plants grown under high light initiated flowers within 45 days from seed germination, while plants grown under low light intensity remained vegetative and produced no flowers during the 60 days of experimental period. Using HPLC, trace amounts (0.52 mg g⁻​¹) of glucose were detected under high light intensity at the beginning of transition from vegetative to floral stage (40 days after germination) which increased to 2.70 mg g⁻​¹ with progressive floral development. No glucose was detected in shoot apices of plants grown under low light during the experimental period. Results indicate that adequate glucose production may be required for floral initiation and development in 'S. formosa'.

Globalization results when markets become more integrated because of reduced transaction and transport costs. These costs have fallen because of sustained advances in transport technology and, more dramatically, in digital information and communication technology (ICT). Although communication costs tend to be a minor component of total trading costs, reductions in these costs may strongly stimulate international trade. The empirical evidence in support of this effect is, however, scant and its strength may depend on the composition of ICT. We test the hypothesis of an ICT effect on trade for the case of trade in flowers. We employ a gravity model of international trade which includes 92 countries and which covers the period from 1995 to 2006. The models explains the volume or value of flower trade in terms of the level of internet and mobile phone diffusion, and of a broad range of factors that might also affect bilateral trade. We tested whether a fixed effects model is appropriate. Mobile phone usage in exporting countries is a significant positive factor influencing trade in cut flowers in both exporting and importing countries, but its impact is less than that of fixed telephone usage. Fixed telephone usage has a significant influence on trade in both exporting and importing countries, but the impact of its usage on the value of trade is greater in exporting countries than in importing countries. Internet usage has a significant and positive effect on trade in importing countries that is comparable in magnitude to that of mobile telephony, but it has no significant effect in exporting countries.

Swainsona formosa (G.Don) J. Thompson (Sturt's desert pea) is an Australian native legume which is used as an ornamental pot plant. It is also suitable for hanging baskets and cut flowers. One of the Impediments to the commercialisation of S. formosa as a pot plant is its inability to produce flowers under light conditions. The possibility of using exogenous sugar application as a replacement for high light intensity conditions is considered with the objective of evaluating the effect of exogenous sugar application on the in vitro flowering of S. formosa. Media containing different sugars (sucrose. fructose and glucose) and concentrations (1.5, 3.0. 4.5 or 6.0% w/v) were used in both high and low light.

'Swainsona formosa' (G. Don) J. Thompson (Sturt's desert pea) is an Australian native legume, which is used as an ornamental pot plant. It is also suitable for hanging baskets and cut flowers. One of the impediments to the commercialisation of 'S. formosa' as a pot plant is its inability to produce flowers under low light conditions. The possibility of using exogenous sugar application as a replacement for high light intensity conditions is considered with the objective of evaluating the effect of exogenous sugar application on the in vitro flowering of 'S. formosa'. Media containing different sugars (sucrose, fructose, and glucose) and concentrations (1.5, 3.0, 4.5, or 6.0% w/v) were used in both high and low light. In vitro flowering of 'S. formosa' depended on light conditions under which the stock plants were grown and on the sugar type and concentration in the culture medium. No flowers were observed in any cultures from low light grown stock plants after six weeks, whereas the explants from the high light grown stock plants cultured on Murashige and Skoog medium containing 3.0% and 4.5% sucrose developed flowers within four to six weeks. These results point to the possibility of an interaction between environmental conditions under which the explant source is grown and the types and concentrations of exogenous sugar used in the culture medium. The work presented here is the first report of 'S. formosa' producing flowers in vitro.

Micropropagation via enhanced axillary shoot proliferation was investigated in the ornamental Eucalyptus cv. 'Urrbrae Gem' using in vitro germinated seedlings and was successfully achieved using woody plant medium (WPM) supplemented with 2.2 μM benzylaminopurine, 1.0 μM α-naphthaleneacetic acid, and 1.5 μM gibberellic acid (GA₃), gelled with 5 g l−1 Phytagel®. Shoot proliferation was greater on WPM and QL media with GA3 compared to B5, AP, and TK media with or without GA3. GA3 was required for shoot elongation as the internodes were otherwise very short and unsuitable for multiplication or root initiation. Root initiation was improved using (1/2) WPM supplemented with 20 μM indole-3-butyric acid (IBA) over a 7 d pulse, followed by subculture to IBA-free medium, compared to placing shoots on low levels of IBA for 4–6 wk. Plantlets were successfully hardened off to the natural environment via a fogger at 67% relative, humidity at 21°C for 3 d and continued to thrive as potted plants. This is the first report of successful, micropropagation in an ornamental eucalypt (subgenus Symphyomyrtus) from seedling explants.

The genus 'Eucalyptus' contains many species suitable for the floriculture and amenity horticulture industries in Australia. A development program has been underway at the University of Adelaide, with the aim of producing new and novel hybrid eucalypt varieties for these industries through controlled pollination between selected ornamental species. As each new hybrid plant reaches reproductive maturity, it is assessed for desirable characters and the very best plants selected for further development, including response to production systems and vegetative propagation. Plants that perform well in cultivation and can be propagated vegetatively will be registered with Plant Breeders Rights and made available through commercial nurseries.

Outcrossing was investigated in interspecific hybrids between self-fertile 'Eucalyptus platypus' Blakely and partially self-sterile 'E. spathulata' Hook., which shows both pre- and post-zygotic timing. Four hybrid trees were used for the study, two with 'E. spathulata' and two with 'E. platypus' as female parent. Each hybrid had a similar number of locules to each other and to the 'E. platypus' parent, and an intermediate number of ovules per flower compared with the parent species. Controlled hand-pollinations were carried out, in which both self- and cross-pollen from the other hybrid tree with the same female parent species was applied to flowers on each of the four trees, and observations were made 10 days, 4 weeks and 8 weeks after pollination and at seed maturity. In all hybrids, mean seeds per capsule was consistently higher following cross-pollination than following self-pollination. All hybrids showed a reduction in pollen tube number between the top and base of the style when examined by fluorescence microscopy. One tree had significantly fewer cross- than self-pollen tubes at the base of the style, but a similar number of ovules was penetrated by pollen tubes following both treatments. In the other three, there was no difference between cross- and self-pollination in pollen tubes in the style. In three of the four trees there was no difference in ovule penetration following self- or cross-pollination, but in the other, more crossed than selfed ovules were penetrated. Light-microscopy observation of ovules indicated that ovule abortion following fertilisation accounted for the reduced numbers of seeds following self-pollination and to a lesser extent following cross-pollination. All four hybrid trees, irrespective of female parent, were partially self-sterile and resembled the partially self-sterile 'E. spathulata' rather than the self-fertile 'E. platypus'. While the timing of outcrossing control of 'E. spathulata' was both pre- and post-zygotic, only one hybrid was similar, with the other three showing post-zygotic control.

An experiment was conducted to investigate the association between endogenous proline and the embryogenic potential of callus mass proliferated from the anther wall tissue of Swainsonia formosa. Callus proliferation was initiated from anthers containing microspores at early- to late-uninucleate stages, pre-treated with water (control) or mannitol starvation at 4 °C for 2 days, and cultured on double-phase B5 medium supplemented with vitamins, 2% sucrose and 49.3 p.M IBA and 4.61 1.1M zeatin. Fico11-400® was added at a 10% (w/v) concentration to enhance embryogenic callus formation. After 4 weeks in total darkness, cultures were placed under cool fluorescent light with an intensity of 50 1.1mol m-2 s-1 for a 16 hour photoperiod at 25 ± 1°C. Somatic embryos were successfully regenerated from embryogenic callus. Nonembryogenic callus continued to grow, and resulted in further callus proliferation when transferred to a regeneration medium supplemented with 1% sucrose and 4.63 tM kinetin. Microscopic observation combined with amino acid analysis of callus tissue using ethanol extraction and sulphosalicylic acid provided strong evidence that embryogenic potential was correlated with endogenous proline content; embryogenic callus contained proline whereas proline was absent in non-embryogenic callus. This suggests that proline quantification may provide an effective biochemical method to assess or to improve the embryogenic potential of callus mass.

Reduced flower pigmentation in the legume 'Swainsona formosa' is associated with increased susceptibility to 'Phytophthora cinnamomi' and other soil-borne pathogens. This study aimed to identify the mechanism for these differences in susceptibility. Chemical analyses of stem tissues that had been previously inoculated with 'P. cinnamomi' revealed that neither anthocyanin nor total phenolic content increased with infection. Such results suggested that observed differences in susceptibility, as indicated by flower colour, were related to preformed rather than induced stem chemistry. Acetone extracts from healthy, uninfected stem tissues of a red-flowered line were highly toxic to the fungus, while extracts from a white-flowered line were non-toxic and those from a pink-flowered line were intermediate in toxicity and this was correlated with the total phenolic and proanthocyanidin concentration of the extracts. Precipitation of proanthocyanidins with bovine serum albumen removed the toxicity of the extracts. It was concluded that differences in the proanthocyanidin content of tissues contributed to the differences in disease susceptibility of plants with different flower colours.

The ongoing eucalypt development programme at the University of Adelaide has produced many hundreds of interspecific eucalypt hybrids suitable for ornamental horticulture. A two-phase selection process was developed to streamline selection; from this process, twelve superior hybrids have been identified for further work, including propagation and production trials. This paper will report on progress towards commercial release.