Growing floricultural crops with brackish water

In the current review we focus on the opportunity to use brackish water in the cultivation of floricultural plants, plants for which, due to their high economic value, growers have traditionally used good quality water for irrigation. Now, even for these crops the use of alternative water sources for irrigating nursery plants is needed because of the limited supplies of fresh water in many countries; understanding how saline water can be used will also enhance sustainable development in floriculture. While salt stress usually reduces plant growth, any such reduction might not be negative for ornamentals, where shoot vigour is sometime undesirable, although on flower crops salt stress can delay flowering or decrease flower quality characteristics. However, a decrease in growth rate is not enough to characterize the salt tolerance of ornamental plants, but traits like tip and marginal leaf burn, as consequence of sodium and chlorine accumulation, have to be considered for their effects on aesthetical value. With this in mind, some halophytes should be considered for floriculture because of their ability to cope with saline environments; their potential to tolerate salt is an important factor in reducing production costs. Consequently, the identification of ornamental halophytes is important for producing a commercially acceptable crop when irrigated with brackish waters. Many aspects of a plant's reaction to salt are genetically determined, so selection of suitable genotypes or breeding for salt tolerance in ornamentals are interesting options. Developing salt-tolerant floricultural crops, together with typical management practices that avoid excessive salinity stress in the root media, will provide the grower with economically and environmentally sound wastewater reuse options.     

Mycorrhiza in floriculture: difficulties and opportunities

Arbuscular mycorrhizal fungi (AMF) establish symbiotic relationships with the roots of about 80% of plant species. The arbuscular mycorrhizal (AM) symbiosis benefits the growth and development of plants, among them a variety of ornamental horticulture (floriculture) plants. AMF have been shown to benefit plants that suffer from stunted growth, including that stemming from abiotic stress. Many floriculture crops are grown in the semi-arid environment of the Mediterranean region, and therefore AMF application may be implemented in floriculture practices to significantly promote crop growth and yield. However, for successful commercial utilization of the AM symbiosis and its introduction into ornamental floriculture practices, several considerations must be taken into account. These are highlighted and examined in the present review. They include the prerequisite of availability of high quantities of good-quality AMF inocula, the need to use different types and dosages of AMF inocula, at different times of inoculation, and the agricultural crop growth practices that are best-suited for integration with AMF inoculation. The difficulties and opportunities in AMF usage in floriculture are discussed and suggestions on different ways to solve the encountered difficulties are made, to promote cost-effective use of AMF in floriculture.     

Practical Applications of Manipulating Plant Architecture by Regulating Gibberellin Metabolism

The international trade in floriculture is estimated to be worth about US$150 billion, with the global demand for ornamentals steadily increasing. Consumer choice is influenced by factors such as plant architecture and flower colour. Conventional breeding has been responsible for the introduction of novel traits into ornamental plants and has played an important role in the development of new cultivars. However, a restricted gene pool and failure of distant crosses have led to the exploitation of somatic cell techniques, particularly genetic transformation, to generate plants with desirable traits. Gibberellins (GAs) are endogenous plant hormones that control key aspects of growth and development. Chemical growth regulators that modify GA biosynthesis are used extensively in horticulture to control plant stature, increasing production costs, manpower, and environmental risks. An alternative strategy involves genetic manipulation of GA metabolism to induce phenotypic changes, particularly alteration of stature. Because ornamentals are not used for human consumption, genetic manipulation approaches with these plants may be more acceptable in the immediate future to the general public, in certain parts of the world, than genetically manipulated food crops.     

A simple and effective method for the micropropagation and in vitro induction of polyploidy and the effect on floral characteristics of the South African iris,Crocosmia aurea

South Africa is home to approximately 10% of the world's flora, many of which are endemic to the country. A large number of South African genera have been improved for horticultural use and many of these are economically important as cut flowers or ornamentals on international markets. The genus Crocosmia, an attractive member of the family Iridaceae, has potential both as an ornamental plant and for cut flower production, although market potential of the species may be increased by improving the size of the flowers and inflorescence. Polyploidy has been used as a tool in the improvement of ornamental plants and has led to the development of several improved ornamental species. This study established a micropropagation protocol for Crocosmia aurea, using seed as the source material. Tetraploidy was induced by treating seeds with colchicine. These seeds were subsequently germinated and multiplied in vitro using the established protocol. The resulting tetraploid plantlets were successfully hardened-off and used to study the effect of the induced tetraploidy on the plant characteristics. The tetraploid (4n) plants were found to have longer, wider leaves as well as longer inflorescence stems and fewer, but larger, flowers than their diploid (2n) counterparts. These polyploid selections have potential in the ornamental/floriculture trade.     

基于花青素代谢培育蓝色花卉的研究进展

花色是植物吸引昆虫传播花粉的主要因素,对于植物在自然界的生存必不可少,也是观赏植物最重要的性状之一。在蓬勃发展的花卉产业中,色彩各异花卉的培育,可以弥补自然花色的匮乏,但是令人垂涎的蓝色花比较难培育。花色的多样性主要是由花青素及其衍生物的种类和含量等因素决定的,飞燕草色素的合成是形成蓝色花的关键因素,许多植物体内缺少合成飞燕草色素的结构基因。近年来,利用基因工程技术培育蓝色花的研究也时有报道。文中以常见的观赏植物为例,基于花青素代谢调控,从影响飞燕草色素合成的关键因素和不同分子改良途径培育蓝色花等几个方面对植物花朵呈色的机制进行了综述,并展示不同分子育种策略可能在其他领域的应用,为其他植物或经济作物的色泽改良如彩色棉蓝色纤维的培育等提供参考和技术支持。     

Best management practices for minimizing nitrate leaching from container-grown nurseries

Containerized plant production represents an extremely intensive agricultural practice; 40,000 to 300,000 containers may occupy one acre of surface area to which a large amount of chemical fertilizer is applied. Currently, recommended fertilizer application rates for the production of containerized nursery ornamental plants are in excess of plant requirements, and up to 50% of the applied fertilizers may run off or be leached from containers. Among the nutrients leached or allowed to runoff, nitrogen (N) is the most abundant and is of major concern as the source of ground and surface water pollution. In this report, current N fertilizer application rates for different container-grown nursery ornamental plants, the amount of nitrate leaching or runoff from containers, and the potential for nitrate contamination of ground and surface water are discussed. In contrast, our best N management practices include: (1) applying fertilizers based on plant species need; (2) improving potting medium's nutrient holding capacity using obscure mineral additives; (3) using controlled-release fertilizers; and (4) implementing zero runoff irrigation or fertigation delivery systems that significantly reduce nitrate leaching or runoff in containerized plant production and encourage dramatic changes in N management.     

Effect of arbuscular mycorrhizal colonization and two levels of compost supply on nutrient uptake and flowering of pelargonium plants

Two challenges frequently encountered in the production of ornamental plants in organic horticulture are: (1) the rate of mineralization of phosphorus (P) and nitrogen (N) from organic fertilizers can be too slow to meet the high nutrient demand of young plants, and (2) the exclusive use of peat as a substrate for pot-based plant culture is discouraged in organic production systems. In this situation, the use of beneficial soil microorganisms in combination with high quality compost substrates can contribute to adequate plant growth and flower development. In this study, we examined possible alternatives to highly soluble fertilizers and pure peat substrates using pelargonium (Pelargonium peltatum L’Her.) as a test plant. Plants were grown on a peat-based substrate with two rates of compost addition and with and without arbuscular mycorrhizal (AM) fungi. Inoculation with three different commercial AM inocula resulted in colonization rates of up to 36% of the total root length, whereas non-inoculated plants remained free of root colonization. Increasing the rate of compost addition increased shoot dry weight and shoot nutrient concentrations, but the supply of compost did not always completely meet plant nutrient demand. Mycorrhizal colonization increased the number of buds and flowers, as well as shoot P and potassium (K) concentrations, but did not significantly affect shoot dry matter or shoot N concentration. We conclude that addition of compost in combination with mycorrhizal inoculation can improve nutrient status and flower development of plants grown on peat-based substrates.     

Protocorm-like bodies (PLBs) of Dendrobium Sabin Blue: a novel source for in vitro production of dendrobine and anthocyanin

In Vitro Cellular & Developmental Biology - Plant - Dendrobium hybrids have been cultivated as commercially important ornamental plants in the floriculture industry. However, the potential of...     

Genetic modification; the development of transgenic ornamental plant varieties

Plant transformation technology (hereafter abbreviated to GM, or genetic modification) has been used to develop many varieties of crop plants, but only a few varieties of ornamental plants. This disparity in the rate and extent of commercialisation, which has been noted for more than a decade, is not because there are no useful traits that can be engineered into ornamentals, is not due to market potential and is not due to a lack of research and development activity. The GM ornamental varieties which have been released commercially have been accepted in the marketplace. In this article, progress in the development of transgenic ornamentals is reviewed and traits useful to both consumers and producers are identified. In considering possible factors limiting the release of genetically modified ornamental products it is concluded that the most significant barrier to market is the difficulty of managing, and the high cost of obtaining, regulatory approval.     

Nanotechnology a novel approach to enhance crop productivity

Nanobiotechnology provides novel set of tools to manipulate and enhance crop production using nanoparticles, nanofibres, nanoemulsions, and nanocapsules. Nanomaterials provide a platform to deliver agrochemicals and various macromolecules needed for plant growth enhancement and resistance to stresses. Smart delivery of agrochemicals increases the yield by optimizing water and nutrient conditions. Another added advantage is controlled release and site-directed delivery of agrochemicals. Further enhancement in quality and quantity in agriculture can be achieved by nanoparticle-mediated gene transformation and delivery of macromolecules that induces gene expression in plants. Various types of nanomaterials have been tested so far and the results have been promising in terms of productivity and quality enhancement.     

Programmed Cell Death in Relation to Petal Senescence in Ornamental Plants

Cell death is a common event in all types of plant organisms. Understanding the phenomenon of programmed cell death (PCD) is an important area of research for plant scientists because of its role in senescence and the post-harvest quality of ornamentals, fruits, and vegetables. In the present paper, PCD in relation to petal senescence in ornamental plants is reviewed. Morphological, anatomical, physiological,and biochemical changes that are related to PCD in petals, such as water content, sink-source relationships,hormones, genes, and signal transduction pathways, are discussed. Several approaches to improving the quality of post-harvest ornamentals are reviewed and some prospects for future research are given.     

Influence of different landscape design styles on plant invasions in Central Europe

When considering the most frequent invasive exotic plants on an international scale, it is evident that the majority are ornamentals and that they were deliberately introduced in relation to landscape design. Although there are worldwide numerous lists of invasive exotic plants—which means plants that have harmful effects on native biodiversity—an assessment of the contribution of different landscape design styles on plant invasions has not been done. We used the extensive database on the history of introduction and naturalization of alien plants into natural habitats of Central Europe (Lohmeyer and Sukopp, Agriophyten in der Vegetation Mitteleuropas in: Schriftenreihe Vegetationskunde 25, 1992; Nachtrag: Braunschweiger Geobotan Arbeiten 8:179–220, 2001) to examine how many alien ornamental plants there are in the different natural habitats; and how many of them are invasive exotic plants and—in contrast—how many have not spread significantly. Also, we researched contributions by different landscape design styles to these plant invasions since medieval times. Of the estimated 12,000 alien plant species introduced into Central Europe since the Neolithic period, 279 taxa (2.3 %) are currently identified as being naturalized in natural habitats; 103 (0.86 %) of these naturalized taxa are ornamentals, and of these, 40 (0.33 %) are invasive exotic plants. Our investigation has shown a correlation between the frequency of plant invasions and changes in landscape-design styles. Evaluating the impact of plant invasions through horticulture and landscape design on native biodiversity, our study illustrates that it is significantly lower in Central Europe than in other parts of the world.     

Biotechnological approaches to breeding and cultivation of ornamental crop plants

Recent advances in plant biotechnology hold great potential for the ornamental horticulture industry. In addition to conventional methods, breeders can now introduce genetic variation into ornamentals by the application of recombinant DNA technology. This technology is particularly useful for effecting changes in phenotypic expression encoded by single genes such as corolla and foliage color and texture, stem length, scent, temporal regulation of flowering, vase life of cut flowers and resistance to stressful environments. In part, the commercial success of this technology will depend on developing reliable methods of transformation of ornamentals and on the stability of the introduced or altered genes. In addition, new and improved strategies of in vitro culture have been commercially implemented for the propagation and breeding of a wide variety of ornamental crops and will undoubtedly play a major role in the screening and propagation of chimeric plants developed by recombinant DNA technology.     

Programmed Cell Death in Relation to Petal Senescence in Ornamental Plants

Cell death is a common event in all types of plant organisms. Understanding the phenomenon of programmed cell death (PCD) is an important area of research for plant scientists because of its role in senescence and the post-harvest quality of ornamentals, fruits, and vegetables. In the present paper, PCD in relation to petal senescence in ornamental plants is reviewed. Morphological, anatomical, physiological,and biochemical changes that are related to PCD in petals, such as water content, sink-source relationships,hormones, genes, and signal transduction pathways, are discussed, Several approaches to improving the quality of post-harvest ornamentals are reviewed and some prospects for future research are given.     

Variety protection by use of molecular markers: Some case studies on ornamentals

ABSTRACT

In vegetatively propagated ornamentals, new varieties can be obtained from i.) conventional breeding and selection or ii.) spontaneous or induced variant types of existing varieties. Indeed, variant types enlarge the assortment to be produced without the need to alter production systems. However, they inherit the breeding effort needed to create a completely new and profitable variety. Therefore, the breeder of the initial variety might want to claim at least part of the profits under the form of a royalty on what is considered as essentially derived varieties (EDV). To detect either EDV or fraud, criteria based on plant morphology are insufficient or even not applicable. Here, some case studies are presented to illustrate the possibilities and the limitations of AFLP fingerprinting in disputes on fraud and essential derivation of ornamental plants. No differences were detected between fingerprints of different azalea bud sports, all belonging to the commercially important “Hellmut Vogel?d group. In roses, it was possible to elucidate the irregular application for breeders' protection for a bud sport of a registered rose cultivar. This was confirmed by fingerprinting the putative parents given in the application file. In Phalaenopsis, a breeder tried to broaden the protection he received on a variant derived from an old free variety, to a similar clone. After fingerprinting, both parties decided to close the case.     

Regulated irrigation of woody ornamentals to improve plant quality and precondition against drought stress

Regulated irrigation has the potential to improve crop quality in woody ornamentals by reducing excessive vigour and promoting a more compact habit. This research aimed to compare the effectiveness and the mode of action of two techniques, regulated deficit irrigation (RDI) and partial root drying (PRD), when applied to container-grown ornamentals through drip irrigation. Results showed that RDI and PRD reduced growth in Cotinus coggygria 'Royal Purple', but in Forsythia x intermedia 'Lynwood', significant reductions were recorded only with RDI. Physiological measurements in Forsythia indicated that reductions in stomatal conductance (g_s) occurred in both treatments, but those in the RDI tended to be more persistent. Reduced g_s in PRD was consistent with the concept that chemical signals from the root can regulate stomatal aperture alone; however, the data also suggested that optimising the growth reduction required a moderate degree of shoot water deficit (i.e. a hydraulic signal to be imposed). As RDI was associated with tissue water deficit, it was used in a second experiment to determine the potential of this technique to precondition container-grown plants against subsequent drought stress (e.g. during retail stages or after planting out). Speed of acclimation would be important in a commercial context, and the results demonstrated that both slow and rapid imposition of RDI enabled Forsythia plants to acclimate against later drought events. This article discusses the potential to both improve ornamental plant quality and enhance tolerance to subsequent adverse conditions through controlled, regulated irrigation.     

Plant-related factors influence the effectiveness of Neoseiulus fallacis (Acari: Phytoseiidae), a biological control agent of spider mites on landscape ornamental plants

The predatory mite Neoseiulus fallacis (Garman) was evaluated as a biological control agent of herbivorous mites on outdoor-grown ornamental landscape plants. To elucidate factors that may affect predator efficiency, replicated tests were conducted on 30 ornamental plant cultivars that varied in relationship to their generalized morphology (e.g., conifers, shade trees, evergreen shrubs, deciduous shrubs, and herbaceous perennials), production method (potted or field grown), canopy density, and the prey species present on each. Plant morphological grouping and foliar density appeared to be the most influential factors in predicting successful biological control. Among plant morphological groups, N. fallacis was most effective on shrubs and herbaceous perennials and less effective on conifers and shade trees. N. fallacis was equally effective at controlling spider mites on containerized (potted) and field grown plants, and there was no difference in control of mites on plants with Tetranychus spp. versus those with Oligonychus or Schizotetranychus spp. Moderate to unsuccessful control of spider mites by N. fallacis occurred mostly on tall, vertical plants with sparse canopies. Acceptable spider mite control occurred in four large-scale releases of N. fallacis into production plantings of Abies procera, Thuja occidentalis 'Emerald', Malus rootstock, and Viburnum plicatum 'Newport'. These data suggest that N. fallacis can be an effective biological control agent of multiple spider mite species in a range of low-growing and selected higher growing ornamental plants.     

Prospects and limitations of microbial pesticides for control of bacterial and fungal pomefruit tree diseases

The tree constitutes an ecosystem in which microorganisms play an essential role in its functionality. Interactions that microorganisms establish with plants may be beneficial or detrimental and are of extreme importance in the exploitation of trees in agriculture as crop production systems. Fruit trees, especially pomefruit trees including apple, pear and several ornamentals are of great economic importance but its production is affected by several diseases. Fungal and bacterial fruit tree diseases are mainly controlled with chemical fungicides and bactericides, but health and environmental concerns about the use of chemical pesticides have result in strong regulatory actions and have stimulated the development of beneficial microorganisms as microbial pesticides. Up to now, several microorganisms have been registered in different countries and in the EU as biocontrol agents (BCA) covering mainly fire blight, soil-borne fungal diseases and postharvest fruit fungal rot. The key aspects in the success of this technology for disease control are related to biosafety and environmental impact of biocontrol agents, the traceability and fate in the environment and food chain, the improvement by physiological, genetic engineering or the use of mixtures or formulations as well as the industrial production and development of delivery systems for treatment application to trees.     

AM真菌在有机农业发展中的机遇

在农田生态系统中,许多农作物均为丛枝菌根(AM)真菌的优良宿主植物,当AM真菌与这些宿主植物建立共生关系之后,AM真菌的存在有益于宿主植物的生长。然而,传统农业耕作模式中化学肥料和农药的施用、耕作制度的不断调整和非宿主植物的种植等都不利于AM真菌的建植。有机农业生态系统排除了化学肥料和农药的施用,减少了对AM真菌生长不利的因素,促进了土壤中AM真菌数量的增加和群落多样性的提高。同时,AM真菌可以通过多种方式改善土壤物理结构、提高农作物对干旱胁迫的耐受能力以及宿主植物对病虫害的抗性/耐性、抑制杂草生长、促进营养物质的吸收,进而提高植物的生长和改善产品的品质。基于此,围绕AM真菌在有机农业发展中的生态学功能展开论述,分析当前有机农业生态系统存在的问题,探讨利用AM真菌发展有机农业的可行性及其发展的机遇,以期促进AM真菌在有机农业发展中的应用。     

A new perspective on the use of plant secondary metabolites to inhibit methanogenesis in the rumen

Recently, greenhouse gas emissions have been of great concern globally. Ruminant livestock due to production of methane during normal fermentation in the rumen contributes substantially to the greenhouse effects. During the recent decade, a paradigm shift has been initiated whether plant secondary metabolites (PSM) could be exploited as natural safe feed additives alternative to chemical additives to inhibit enteric methanogenesis. More than 200,000 defined structures of PSM have been known. Some plants or their extracts with high concentrations of bioactive PSM such as saponins, tannins, essential oils, organosulphur compounds, flavonoids and many other metabolites appear to have potential to inhibit methane production in the rumen. The possible mechanisms and effects of many PSM on rumen methanogenesis are not clearly understood. Saponins may decrease methanogenesis through the inhibition of rumen protozoa and in turn may suppress the numbers and activity of methanogens. Although the direct effect of saponins on methanogens has not been demonstrated, saponins might inhibit methanogens at high doses. Tannins may inhibit the methanogenesis directly and also via inhibition of protozoal growth. Essential oils, organosulphur compounds and flavonoids appear to have direct effects against methanogens, and a reduction of protozoa associated methanogenesis probably plays a minor role for these metabolites. The chemical structure and molecular weight of the PSM and chemical composition of diets dependent upon the different feeding regimes may influence the effects of PSM on methane production. Although PSM may negatively affect nutrient utilization, there is evidence that methanogenesis could be suppressed without adversely affecting rumen fermentation, which could be exploited to mitigate methane emission in ruminants.