More than symbioses : orchid ecology ; with examples from the Sydney Region

The Orchidaceae are one of the largest and most diverse families of flowering plants. Orchids grow as terrestrial, lithophytic, epiphytic or climbing herbs but most orchids native to the Sydney Region can be placed in one of two categories. The first consists of terrestrial, deciduous plants that live in fire-prone environments, die back seasonally to dormant underground root tubers, possess exclusively subterranean roots, which die off as the plants become dormant, and belong to the subfamily Orchidoideae. The second consists of epiphytic or lithophytic, evergreen plants that live in fire-free environments, either lack specialised storage structures or possess succulent stems or leaves that are unprotected from fire, possess aerial roots that grow over the surface of, or free of, the substrate, and which do not die off seasonally, and belong to the subfamily Epidendroideae. Orchid seeds are numerous and tiny, lacking cotyledons and endosperm and containing minimal nutrient reserves. Although the seeds of some species can commence germination on their own, all rely on infection by mycorrhizal fungi, which may be species-specific, to grow beyond the earliest stages of development. Many epidendroid orchids are viable from an early stage without their mycorrhizal fungi but most orchidoid orchids rely, at least to some extent, on their mycorrhizal fungi throughout their lives. Some are completely parasitic on their fungi and have lost the ability to photosynthesize. Some orchids parasitize highly pathogenic mycorrhizal fungi and are thus indirectly parasitic on other plants. Most orchids have specialised relationships with pollinating animals, with many species each pollinated by only one species of insect. Deceptive pollination systems, in which the plants provide no tangible reward to their pollinators, are common in the Orchidaceae. The most common form of deceit is food mimicry, while at least a few taxa mimic insect brood sites. At least six lineages of Australian orchids have independently evolved sexual deception. In this syndrome, a flower mimics the female of the pollinating insect species. Male insects are attracted to the flower and attempt to mate with it, and pollinate it in the process. Little is known of most aspects of the population ecology of orchids native to the Sydney Region, especially their responses to fire. Such knowledge would be very useful in informing decisions in wildlife management

Pollination ecology of New Zealand orchids : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Ecology at Massey University

The New Zealand orchid flora comprises twenty-five genera and at least 100 species occurring throughout the country. Although the number of endemic species is high (69%) only four genera are endemic to New Zealand. The main physical threats to orchid survival in New Zealand are habitat destruction, modification and fragmentation. The effect of the disruption of interactions with their pollinators has never been considered. This study concentrates on this mutualistic interaction, by assessing the breeding system, pollination syndromes and pollinator-dependence of four widespread terrestrial (Gastrodia cunninghamii, Thelymitra longifolia, Pterostylis alobula and P. patens) and four widespread epiphytic orchids (Earina autumnalis, E. aestivalis, E. mucronata and Winika cunninghamii) occurring in the southern portion of the North Island. In order to determine the breeding system and the presence of self-incompatibility, hand-pollination treatments were conducted in all eight orchid species during the flowering seasons of 2001 and 2002. Pollen grains and ovules numbers, pollen:ovule ratio and presence of floral scent glands were assessed. In those nectariferous species (E. autumnalis, E. aestivalis, E. mucronata and W. cunninghamii), the nectar standing crop was determined using the anthrone colorimetric assay for total carbohydrates. The activity of pollinator was observed both in the field and in captivity. Insects observed foraging in these orchids were identified and ranked according to their likely pollination effectiveness. Finally, measurements of pollination success and pollinia removal and deposition were used to assess whether fruit-set is pollen limited in these species and explore the effect contrasting rewarding strategies (nectar v/s deception) has on the pollination success of these orchids. Pollination treatments in three terrestrial (T. longifolia, P. alobula and P. patens) and two epiphytic (E. autumnalis and E. mucronata) orchids confirmed the absence of genetic incompatibility. Despite these five orchids being self-compatible, their reproduction relies on contrasting reproductive strategies. T. longifolia is predominantly self-pollinated, whereas Pterostylis and Earina species are incapable of autonomous selfing and completely dependent on pollinators. The epiphytic species E. aestivalis and W. cunninghamii are partially self-incompatible and also completely dependent on pollinators. Agamospermy is likely to occur in G. cunninghamii but not involved in seed-production in any of the remaining seven orchids. Both terrestrial and epiphytic species showed a positive reaction to neutral red except E. autumnalis. This indicated the presence of scent glands, mainly located around the column, lip and sepal tips. Pollen:ovule ratios calculated for these species ranged from 20:1 in E. mucronata and E. aestivalis to 320: 1 in P. alobula. Of the four terrestrial orchids studied, insect visitation was observed only in P. alobula. This orchid is pollinated by male fungus gnats of the genus Zygomyia (Diptera: Mycetophilidae). Pollination by sexual deception is likely to occur in species of this genus. Numerous insects were recorded visiting the nectariferous epiphytic orchids (3 orders, 13 families). Insects considered as "probable pollinator" were Eristalis tenax (Diptera: Syrphidae) for Earina autumnalis, Dilophus nigrostigmus (Diptera: Bibionidae) for E. mucronata, and Melangyna novaezealandiae (Diptera: Syrphidae), Calliphora quadrimaculata (Diptera: Calliphoridae), the Ichneumonid wasp Aucklandella sp. (Hymenoptera: Ichneumonidae), Hylaeus sp. (Hymenoptera: Colletidae) and an unidentified weevil (Coleoptera: Curculionidae) for E. aestivalis. In W. cunninghamii the species Apis mellifera and the native syrphid flies Helophilus antipodus and M. novaezealandiae were considered as "probable pollinators". Levels of natural fruit-set were similarly low in rewarding and non-rewarding species fluctuating from 4.3% (P. alobula) to 40% (P. patens). Fruiting in these orchids is pollen limited, as supplementary hand-pollinations increased fruit set above 40% in all species except P. patens. The degree of pollen limitation varied from 0.32 (P. patens) and 0.94 (P. alobula and E. mucronata). Pollen limitation in these orchids may be caused by the simplicity of their flowers, the poor efficiency of their pollinators in depositing pollinia and the use of species-specific pollination systems (e.g. Pterostylis). The survival capability and conservation requirements of these orchids are discussed in the light of the specific reproductive requirements revealed by this study

Further advances in orchid mycorrhizal research

Orchid mycorrhizas are mutualistic interactions between fungi and members of the Orchidaceae, the world’s largest plant family. The majority of the world’s orchids are photosynthetic, a small number of species are myco-heterotrophic throughout their lifetime, and recent research indicates a third mode (mixotrophy) whereby green orchids supplement their photosynthetically fixed carbon with carbon derived from their mycorrhizal fungus. Molecular identification studies of orchid-associated fungi indicate a wide range of fungi might be orchid mycobionts, show common fungal taxa across the globe and support the view that some orchids have specific fungal interactions. Confirmation of mycorrhizal status requires isolation of the fungi and restoration of functional mycorrhizas. New methods may now be used to store orchid-associated fungi and store and germinate seed, leading to more efficient culture of orchid species. However, many orchid mycorrhizas must be synthesised before conservation of these associations can be attempted in the field. Further gene expression studies of orchid mycorrhizas are needed to better understand the establishment and maintenance of the interaction. These data will add to efforts to conserve this diverse and valuable association

Pemanfaatan Anggrek Sebagai Bahan Obat Tradisional Pada Etnis Batak Sumatera Utara [Utilitation of Orchids as Medicinal Plants by Ethnic Batak of North Sumatra]

Sumatra has rich diversity of orchids. The local communities in Sumatra have been used orchids as a ornamental plant, food, and medicine. Research on utilitation of orchids as medicinal plants by ethnic Batak of North Sumatra was conducted using ethnobotanical methods. The objectives of the research was to know species of orchids that were used as medicinal plants by Batak ethnic in North Sumatra. Respond-ents consisted of traditional medicine plants traders in the traditional markets and traditional healers. We found as many as seven species of 6 genera of orchids have been used as traditional medicine. Those orchids used as medicine for fever, aphrodisiac, maintain stamina, respira-tory disorders, and gastrointestinal disorders

Fungal specificity bottlenecks during orchid germination and development.

Published versio

PB1634-Growing Orchids in the Home

Orchids are becoming increasingly popular as flowering houseplants due to improved cultivars and affordability. Once considered a rich person’s hobby, orchids are now more affordable, thanks to recent advances in propagation techniques. Since the first attempt to grow orchids in the mid-1700s, they have had a reputation for being difficult to grow; however, many orchids are as easy to grow as houseplants. Orchids are quite resilient, and can survive many years in the home with proper care. Orchids are in the family Orchidaceae (or-kid-ACE-eeee). The orchid family includes more than 900 genera and about 25,000 species, making it one of the largest families of flowering plants in the world. Orchids can be found in nearly every environment in the world. Most of the orchids grown in the home are native to the tropical and subtropical areas of South America. They are usually epiphytic, meaning they grow on the sides of trees, or lithophytic, meaning they grow on rocks. Orchids originating from temperate regions of the world are generally terrestrial, meaning they grow in the soil. Orchids are valued mostly for their exquisite flowers, which are available in a vast array of colors from tints of blue, yellow, white, orange and red to almost black. Some blooms are striped or spotted with intricate combinations of color. The blooms can last from one week to four months, depending on the species. Given the proper growing conditions, some orchids may bloom continuously throughout the year, while others may bloom only once per year. The foliage is usually a medium-green, but some orchids have beautiful leaves with intricate mottling and variegation. Many orchids are fragrant. While some may smell like rotted meat, others have more pleasant fragrances like lemon, orange, chocolate, hyacinth, cinnamon, wintergreen, watermelon and coconut

The effect of population structure, plant size, herbivory and reproductive potential on effective population size in the temperate epiphytic orchid, Sarcochilus australis

Distribution of plant size and reproductive success is investigated in the temperate epiphytic orchid Sarcochilus australis (Lindl.) Rchb. f. at Kinglake National Park, Victoria, in south-eastern Australia, and applied to estimating the effective population size. Plant size distribution (leaf number, length of longest leaf and number of flowers) was not normally distributed. Most individuals were vegetative and it is estimated that more than half of all individuals are too small to flower, however exceptionally large individuals even though rare are able to have more than one active inflorescence. Flowering probability is plant size dependent and follows a sigmoid curve. The minimum observed leaf size of a flowering individual was 26 mm, however these small individuals have a low probability of flowering ( 80 mm) have a much higher probability of flowering (90%). The effective population size (Ne) of the Kinglake population of Sarcochilus australis was estimated from the distribution of flower production, and shown to be small (Ne = 10–19%) and comparatively similar to some of the other published estimates of effective populations size in orchids. From this basic survey of size distribution in Sarcochilus australis it is predicted that genetic diversity is low

IDENTIFIKASI JENIS ANGGREK EPIFIT (Orchidaceae) DI KAWASAN ARBORETUM SYLVA UNIVERSITAS TANJUNGPURA PONTIANAK

Arboretum Sylva UNTAN is an ex-situ germplasm conservation area, which has a variety of trees and undergrowth plants including epiphytes. Epiphytic orchids are orchids that grow riding on other plants, but do not harm the host plant. It is important to know the type of epiphytes that hitchhike on host plant can help management in the conservation of the area. For this reason, Epiphytic orchids and their host plant need to be done. This study uses a survey method, with census data collection techniques. Based on the results of the study, 49 types of epiphytic orchids were found as epiphytic orchids belonging to 23 genera and 36 host plant species. Epiphytic orchids that oppose the genus Bulbophyllum and Dendrobium. The dominance of the highest tree species in Acacia sp and A. pavonina. It has nothing to do with epiphytes with host plant species, but epiphytic orchids mostly found on the cantilever plant that has thicker bark, groove bark, stringy bark and a tough bark. Abiotic conditions The environment can distinguish species in the block area.Keywords: Epiphytes orchids, identification, Arboretum Sylva UNTAN