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Part I Orchid seeds are nearly microscopic in size. Because of that, many fanciful theories were proposed for the origin of orchids. Almost 400 years separate the time when orchid seeds were seen for the first time and the development of a practical asymbiotic method for their germination. The seeds were first observed and drawn during the sixteenth century. Seedlings were first described and illustrated in 1804. The association between orchid and fungi was observed as early as 1824, while the requirement for mycorrhiza for seed germination was established in 1899. An asymbiotic method for orchid seed germination was developed in 1921. After Knudson's media B and C were formulated, orchids growing and hybridization became widespread. Hybrids which early growers may not have even imagined became possible. Part II A commonly held view is that Prof. Georges Morel is the sole discoverer of orchid micropropagation and that he was the first to culture an orchid shoot tip in 1960. In fact, the first in vitro orchid propagation was carried out by Dr. Gavino Rotor in 1949. Hans Thomale was the first to culture an orchid shoot tip in 1956. The methods used by Morel to culture his shoot tips were developed by others many years before he adapted them to orchids. This review also traces the history of several techniques, additives, and peculiarities (agitated liquid cultures, coconut water, banana pulp, a patent and what appears to be an empty claim) which are associated with orchid micropropagation. A summary of plant hormone history is also outlined because micropropagation could not have been developed without phytohormones. © 2009 Korean Society for Plant Biotechnology and Springer.

Plants of Tillandsia balbisiana, T. paucifolia, T. recurvata and T. utriculata exposed to 0.15, 0.30 or 0.45 ppm O3 or to 0.30, 0.60 or 1.20 ppm SO2 for 6 hr or sequentially to 0.30 ppm O3 (2 hr), 0.30 ppm O3 plus 0.60 ppm SO2 (2 hr) and 0.60 ppm SO2 (2 hr) did not exhibit visible injury. Fumigations also had no effect on foliar conductance or on ΔH+ associated with Crassulacean acid metabolism. Characteristics responsible for plant tolerance to short exposures to these two gases probably included low stomatal conductance, the insulating indumentum of absorbing foliar hairs and inherently slow metabolism. Reasons for postulating that Tillandsia is a better indicator for technological metals and certain other pollutants than for brief exposures to O3 and SO2 are discussed. We also conclude that epiphytic Tillandsia spp. offer advantages over lichens for air quality assessments under appropriate conditions. As vascular plants they exhibit sensitive, easily measured responses to stress and can be transplanted with ease to areas where neither they nor lichens occur naturally. © 1992.

Axillary buds of taro (Colocasia esculenta var. esculenta, Araceae) cultured on half strength Murashige-Skoog medium (HMS) containing taro extract (HMSTE) and 2, 4, 5-trichlorophenoxyacetic acid produce a compact, hard, slow growing callus which is not very active morphogenetically and produces only a few plantlets. When cultured on HMSTE plus 5 mg 1(-1) each of naphthaleneacetic acid and benzyl adenine (HMSNB) the buds produce a fast growing, friable and morphogenetically active callus. Meristematic regions form on the friable callus after 30 days on HMSNB. If transferred to HMSTE at this point the callus gives rise to plantlets. Addition of taro extract to the media is required for the culture of buds, induction of callus and plantlet regeneration.

Axillary bud expiants from South Pacific (Solomon Islands) taro, Colocasia esculenta var. esculenta cv. Akalomamale (Araceae) cultured on a modified Murashige-Skoog medium containing 1 mg NAA 1(-1) and TE formed callus and produced multiple plantlets. Explants died if NAA was present at levels lower than 0.1 mg 1(-1). BA was not required and may have been inhibitory. Plantlets developed faster and became larger following transfer to a hormone-free medium two weeks after the start of culture. Fully grown plants were established in a potting mix and are growing well in a greenhouse.

Excised lateral buds of taro [Colocasia esculentar var. esculenta (L.) A.F. Hill] developed into plantlets and formed callus if cultured on media containing taro extract. .alpha.-Naphthaleneacetic acid enhanced the process but only if taro extract was also present. The tissue requirements for this variety of taro are different from those of Colocasia esculenta var. antiquorum (L.) A.F. Hill.

Plants of Encyclia tampensis (Epidendrum tampense) and Epidendrum rigidum (Orchidazeae) exposed to 0.3, 0.6 and 1.2 ppm SO2 or 0.15, 0.3 and 0.45 ppm O3 for 6 hr as well as sequentially to 0.3 ppm O3 (2 hr), 0.3 ppm O3 plus 0.06 ppm SO2 (2 hr) did not exhibit visible injuries. Exposures to pollutants were also without effect on stomatal conductance and Crassulacean acid metabolism (CAM, i.e. carbon fixation at night). The leaf resistance of the two orchids to these gases may be due to structural factors as well as to the generally lower sensitivity of CAM plants to pollutants. © 1990.

Evidence obtained from incubation of corn (Zea mays cv. Golden Bantam) seedlings in dl-[benzene ring-U-(14)C]tryptophan, l-[5-(3)H]tryptophan, l-[U-(14)C]aspartate and [U-(14)C]glycerol indicates that niacin is synthesized in these plants via oxidative degradation of tryptophan. Aspartate and glycerol do not appear to be precursors of niacin in corn seedlings.

Specialized epidermal trichomes on the leaves of the epiphyte, Tillandsia paucifolia (Bromeliaceae) accumulate amino acids from solution. Simultaneous net uptake of 17 amino acids was determined using high performance liquid chromatography. Uptake occurs against concentration gradients at least as high as 10(4).

Salinity tolerant taro tissues were selected and cultured in vitro on saline media (50-350 mOsm). Salt tolerance in these tissues was associated with increased levels of calcium oxalate, chlorophyll, protein and some secondary alkaloids. The concentration of other secondary alkaloids as well as the levels of quaternary alkaloids decreased. Calcium, potassium, magnesium and sodium content of the tissues decreased with increased salinity. These findings are discussed in relation to salinity tolerance in taro. © 1989.

Rhizoctonia repens M 32, a mycorrhizal isolate from Orchis militaris requires both a carbohydrate (glucose or sucrose) and an amino acid (aspartic acid, glycine, serine, or glutamic acid) for growth. The fungus does not require an exogenous supply of vitamins in vitro. © 1975 Dr. W. Junk bv - Publishers.

Amphotericin B, benomyl, gentamycin, nystatin, quintozene penicillin G, sodium omadine, and vancomycin singly and in several combinations have no deleterious effects on the germination of orchid seeds, but inhibit the growth in vitro of shoot tip explants. © 1981 Martinus Nijhoff/Dr W. Junk Publishers.

A computer enhanced video microscopy system can be used to study the morphometry of chloroplasts and cells of Colocasia esculenta var. antiquorum. This system is rapid and accurate, and enhances microscopic images, thereby facilitating measurements. It also introduces automation in statistical analyses. © 1987.

Cultured tissues of taro, Colocasia esculenta var antiquorum, were grown on modified Linsmaier-Skoog medium with and without the addition of 50-350 mOs (5-35%) artificial seawater (ASW). Cell wall thickness and cross-sectional area were variable, but not significantly different over the range of ASW concentrations from 0 to 300 mOs. However, cells at 350 mOs ASW did have significantly thinner walls and smaller cross-sectional areas. Of the organelles observed, plastids appeared to be the most sensitive to increasing ASW concentrations. There were more plastids per unit area at 350 mOs ASW than at any other concentration, but their size was reduced. The ratio of amyloplasts to chloroplasts increased with increasing ASW levels. Mitochondrial and nuclear membranes did not seem to be affected by the ASW concentrations used. At high ASW levels, nucleoli showed a loss of electron density in their central regions. © 1987.

Removal of floral segments from Dendrobium (Orchidaceae) flowers indicates that resupination may be regulated or is at least affected by pollinia and/or stigmas. Other floral segments do not appear to have a direct effect. However, excision of the perianth may result in senescence and death, which could be caused by desiccation and/or ethylene evolution.

Dieffenbachia may well be the most toxic genus in the Araceae. Calcium oxalate crystals, a protein and a nitrogen-free compound have been implicated in the toxicity, but the available evidence is unclear. The plants have also been used as food, medicine, stimulants, and to inflict punishment. © 1982.

Surfactants, representing 3 non-ionic and 1 amphoteric series of homologs exhibited marked differences in their lethal and non-toxic effects on HeLa cells. Toxicity of non-ionics generally decreased inversely with increasing hydrophilic chain length and increased with increasing size of the lipophile. Lethal levels of the surfactants coincided with surface tension reduction of the media to 45 dynes cm-1 or below. Surface tensions of non-toxic concentrations were substantially higher than those for toxic levels. Non-toxic doses were, therefore, below the critical micelle concentration of the surfactants evaluated. The data suggest that physical properties are a principal cause of the toxic effects of these detergents on HeLa cells.

Seedlings and leaf discs of C. skinneri incorporated label from 14C- and 3H-labeled tryptophan into niacin. Label from [14C]glycerol and [14C]aspartate was not significantly incorporated into the vitamin.

Auxin (naphthaleneacetic acid [NAA]) application to Cymbidium stigmas (25 .mu.g/flower) induced high rates of ethylene evolution by the flowers within 18 h of the treatment. Actinomycin D reduced the rate of ethylene evolution if applied with the auxin or 2 h after it. Cycloheximide reduced ethylene production regardless of time of application. Puromycin had an inhibitory effect if applied 1 or 2 h after the auxin. Ethionine if applied with the auxin or 1 or 3 h after it, induced more rapid ethylene production and higher evolution rates than NAA alone. Applications of ethionine 2 h after the auxin reduced the levels of ethylene evolution but not the rates or induction time. Anthocyanin levels decreased when each inhibitor was applied together with the auxin. Actinomycin D, cycloheximide, or puromycin, given 1 h after auxin application, did not reduce anthocyanin levels while ethionine did. Initial synthesis of anthocyanins may depend primarily on preexisting RNA and proteins; subsequent production requires de novo RNA and protein synthesis. Ethionine may be a specific inhibitor of anthocyanin production. Of the additional postpollination phenomena exhibited by Cymbidium flowers, some are sensitive to RNA and protein synthesis inhibitors and others are not.

Two naturally occurring orchid phytoalexins, orchinol and loroglossol; a synthetic analog, dehydroorchinol; a possible precursor of orchinol (3,4’-dihydroxy-5-methoxydihydrostilbene); and batatasin III (3,3’-dihydroxy-5-methoxydihydrostilbene) reduced the growth of C. aurantiaca seedlings. These compounds had no effect on the length of the 1st leaves during early stages of development.

Pollination causes increases in FW [fresh wt] and DW [dry wt] of Cymbidium ovaries and gynostemia. It also initates FW losses in perianth segments. Auxin (NAA) [naphthaleneacetic acid] applications to the stigma have the same effects except that FW of ovaries decreases. All segments of unpollinated flowers increased in DW, whereas FW variations were minimal. These weight changes reflect the aging and subsequent death and/or redifferentiation and further development of pollinated and/or unpollinated orchid flowers.

Phytotoxicity of a homologous series of sulfobetaine surfactants, 3-(alkyldimethyl-ammonio)-1-propanesulfonates, on Brassocattleya orchids increased with alkyl chain length from 8 to 14 C atoms of the lipophile, levelled off and then declined with the 18-C derivative. Because of its high Krafft point the latter had reduced solubility at the assay temperature. Interfacial tensions of the nutrient solutions, measured against a test lipid, declined in parallel with the observed phytotoxicity. Disruption of cellular membranes by surface active agents apparently plays a key role in their toxicity.

Observations of flower buds of Dendrobium Tomie ’Tokyo’, Dendrobium ’Indonesia’, and seedlings of a Dendrobium hybrid flowering for the 1st time showed that all flower buds were borne with the labellum uppermost. Just before or during opening, the buds turned, positioning the lip below all other floral segments in a process known as resupination. The degree of turning depended on the orientation of the inflorescence relative to the ground and position of the pedicel. Individual flowers, at successive nodes along the inflorescence, alternated in turning clockwise and counterclockwise. Only buds, flowers in the process of opening, and newly opened blossoms can undergo resupination. Mature flowers cannot reorient themselves if the angle of the inflorescence is changed, and bending and twisting of the pedicel contribute to the final position of the flower.

In C. aurantiaca seedlings, ethephon (2-chloroethylphosphonic acid, also known as Ethrel), slightly accelerated leaf development at concentrations between 2.5 and 20 ppm but suppressed it at 50 ppm. It inhibited leaf length at concentrations of 2.5, 5 and 50 ppm but enhanced it at 10 and 20 ppm. Root formation was inhibited by concentrations higher than 2.5 ppm. Chlorophyll content of seedlings was highest on a medium containing 5 ppm ethephon.

Seeds of several terrestrial orchid species native to the USA were germinated on a number of culture media under differing conditions [nutrients, hormones and light]. Germination rates and seedling development varied considerably.

Roots, stems, petioles and leaf blades of mature plants of P. hysterophorus and callus cultures derived from explants of these organs from aseptically grown seedlings were screened for the presence of sesquiterpene lactones. Parthenin was not detected in roots but was present in callus cultures from all sources. Coronopilin was detected only in petioles and leaf blades and callus cultures derived from these organs. Synthesis of parthenin and coronopilin apparently is not limited to the glandular trichomes.

Seeds of C. aurantiaca grown asymbiotically on a medium containing sucrose as the sole source of organic carbon developed into leaf-bearing plants. Those sown on the same medium without sugar reached the protocorm stage but did not differentiate further. Cross transfers of seedlings between the 2 media indicated that following 21-30 days of growth on the sucrose-containing medium, subsequent development may proceed in the absence of sugar. Levels of chlorophyll and ribulose-1,5-diphosphate carboxylase were monitored and related to the ability of young seedlings to photosynthesize. A direct relationship between chlorophyll content and photosynthesis was not found. Increases in the activity of the enzyme were closely paralleled by increases in photosynthesis. A direct relationship was not found between chlorophyll a/b ratios and photosynthetic capacity. Germinating seeds and seedlings grown in the absence of exogenous carbohydrate were unable to convert appreciable amounts of labeled acetate to sugar.

The major portion of IAA-2-14C, applied to stigmas of whole flowers of Angraecum cv. Veitchii and Cattleya cv. Porcia Cannizaro, as well as to excised gynostemia of the latter, was immobilized at the point of application. A limited amount of nonpolar transport occurred. Some of the auxin was conjugated into IAA-aspartate in a process which is inhibited by cycloheximide, suggesting a requirement for de novo protein synthesis. Because the effects of pollination and auxin application spread quickly to floral segments, additional substances, from pollen or produced by pollinated flowers, may participate in the regulation of postpollination phenomena in orchid flowers.

Pollination or treatment with naphthaleneacetic acid, 50 .mu.g per flower, prevented the death of gynostemia on blossoms of Cattleya Porcia ’Cannizaro’. Auxin treatments, as well as emasculation and pollination, increased anthocyanin levels. After applications of indoleacetic acid (IAA)-2-14C, stigmatic extracts contained IAA, IAA-aspartate and other degradation products. Cycloheximide and actinomycin D reduced the formation of IAA-aspartate. Some of the postpollination phenomena exhibited by Cattleya Porcia ’Cannizaro’ are similar to those of other orchids. Light and electron microscopic studies showed that removal of the pollinia damages the outer cells of the rostellum of Phalaenopsis flowers. Cells in some regions of the ground tissue of the rostellum close to a vascular bundle contain relatively large numbers of mitochondria. These observations suggest that the rostellum is well adapted for ethylene production. The initial evolution of ethylene may result from wounding, which, in turn, probably causes increased production of the hormone.

Removal of floral segments from Dendrobium (Orchidaceae) flowers indicates that resupination may be regulated or is at least affected by pollinia and/or stigmas. Other floral segments do not appear to have a direct effect. However, excision of the perianth may result in senescence and death, which could be caused by desiccation and/or ethylene evolution.

Rapid separation and determination of tryptophan, N-formylkynurenine, kynurenine, 3-hydroxykynurenine, 3-hydroxyanthranilic acid, nicotinic acid, nicotinamide, trigonelline, kynurenic acid and xanthurenic acid from pea seedling using reverse-phase high-pressure liquid chromatography is described. Accuracy of the determinations was > 5%, and < 50 pmol of each metabolite could be measured reliably.

Germination periods extended from several weeks to almost 2 yr.-from Authors

An antifungal factor isolated from extracts of Cymbidium (Orchidaceae) roots and infected pseudobulbs was identified as monolinolein. © 1980 Kluwer Academic Publishers.

Effects on hydra of five homologous series of surfactants representing nonionic, amphoteric and anionic classes were examined. When concentrations which had no effects were increased tenfold the animal disintegrated within 24 h. Lethal concentrations always coincided with a surface tension of 49 ± 4 dynes/cm. This is probably the level which disrupts the cell membranes. Because the deleterious effects are very rapid and obvious, hydra is a useful organism for monitoring the potential toxicity of detergents in freshwater environments. © 1978.

The well known algistatic effect of cationic surfactants was not exhibited by homologous series of amphoteric, anionic and non-ionic types assayed with Chlamydomonas reinhardi. Sulphobetaine amphoterics, 3-(octyl-octadecyldimethylammonio)-1-propanesulphonates, caused growth inhibition when the lipophile contained twelve or more carbon atoms, but only at micellar concentrations. Critical micelle concentration (CMC) of sulphobetaines decreases logarithmically with increasing alkyl chain length and derivatives having eight and ten carbons in the lipophile were below the CMC at the highest concentration tested. Despite their pronounced protein-denaturing properties, sodium higher alkylsulphates did not materially inhibit the growth of Chlamydomonas. This may be due to the fact that the Kraft points of these anionics having fourteen or more carbon atoms were above the culture temperatures, thereby reducing their solution properties. Although less inhibiting than the sulphobetains, the non-ionic alcohol ethoxylates decreased growth with increasing hydrophilicity. The most lipophilic non-ionic showed growth-promoting effects. © 1983.