Germination Of Orchid Seeds Research Articles

Novel Laboratory Exercises in Plant Tissue Culture: In Vitro Asymbiotic Germination of Orchid Seeds

In vitro asymbiotic seed germination, subculture, and outplanting of orchids is presented as a laboratory exercise suitable for students of plant propagation or tissue culture. Dendrobium antennatum (Lindley), Phalaenopsis (Blume) white hybrid, or both, are used in this exercise because they flower predictably in the greenhouse, are reliable for seed production, and germinate and grow rapidly in vitro. The exercises can be used to instruct students in the skills involved in orchid seed sterilization, sowing, and culture, as well as instruct students in the unique features of orchid reproductive biology and symbiosis. A schedule is suggested for stock plant flower pollination, capsule harvest, seed sowing, and seedling subculture so that the necessary plant material is available for students to sow, subculture, and outplant seedlings during a single laboratory session.

Plant biotechnology as a tool in ornamental horticulture

Plant biotechnology, or “In vitro culture of higher plants”, is defined as the culture and manipulation of plants, embryos, organs, explants, tissues, cells and protoplasts on nutrient media under sterile conditions. Plant biotechnology has shown a spectacular development since 1975, resulting in the production and regeneration of viable individuals of many plant species. In addition, since 1980 there has been an explosion in the development of genetic manipulation techniques. <em>In vitro </em>culture of higher plants has become an important tool, particularly in ornamental horticulture and plant breeding. The applications can be summarized as follows: embryo culture, germination of orchid seeds, cloning of orchids, production of disease free plants, micropropagation of many plant species, somaclonal variation, <em>in vitro </em>fertilization, induction of haploids, genetic manipulation, transformation, and a number of miscellaneous applications (e.g. mutation induction, separation of chimaeras, isolation of mutations, chromosome doubling, storage of plants at low temperatures biosynthesis of chemicals, etc.)

The Development and Mobilisation of Seed Reserves in Some African Orchids

The development, final appearance and digestion (during germination) of seed reserves in a number of genera of the Orchidaceae (tribe Orchideae) has been studied comprehensively, using ultrastructural and histochemical techniques complemented by gas chromatographic analysis of free sugars. Mature seeds of Disa, Disperis and Huttonaea contain substantial reserves of lipid and protein in the embryo. The protodermal cells of Disperis also contain protein-carbohydrate bodies. Free sugars are present but starch occurs only in immature seeds. Glyoxysomes are absent and lipolysis does not occur in seeds incubated without an external source of sucrose, and although a little starch is formed it is apparently synthesised from endogenous sucrose reserves. In the presence of exogenous sucrose, however, proteins are hydrolysed and glyoxysomes appear. Substantial quantities of starch are formed in such seeds. From these observations it is apparent that orchid seeds are unable to utilise endogenous reserves of lipid unless simple sugars are supplied to the medium but can utilise the free sugars present in the embryo. Resultant conclusions on the role of mycorrhizae in the germination of orchid seeds are discussed.

An history of orchid hybridization, seed germination and tissue culture

Orchids were probably hand-pollinated for the first time in 1797–1799 by the German botanist, J. K. Wachter. The earliest description of orchid seedlings (Orchis morio and Bletia verecunda), was by the British botanist, R. A. Salisbury, in a paper delivered in 1802 and published in 1804. Germination of an orchid (Prescottia plantaginea) in a horticultural establishment was initially reported from the Horticultural Society garden at Chiswick, U.K. in 1822 or 1832. However, the first detailed and substantiated report on the subject was published by D. Moore, Director of the Glasnevin Botanical Garden in Ireland in 1849. This lead to the first orchid hybrid which was produced by J. Dominy of Messrs Veitch & Sons of Exeter, U.K. in 1856. Fifty years later the French botanist Noel Bernard discovered the role of mycorrhiza in orchid seed germination. Methods for asymbiotic germination of orchid seeds were formulated by the American plant physiologist L. Knudson. The first attempt to propagate an orchid (Phalaenopsis) by tissue culture methods was made by G. Rotor at Cornell University. Shoot tip culture methods for orchids, developed by G. Morel in France in 1960, utilized techniques used for Tropaeolum and Lupinus by E. A. Ball in the U.S.A. as early as 1946.

Terrestrial Orchid Seed Germination in Vitro on a Defined Medium1

Abstract Seeds of 29 terrestrial orchid species representing 15 genera were surface sterilized by immersion in 0.5% sodium hypochlorite containing a wetting agent, washed, sown on a completely defined, semisolid embryo culture medium containing macro- and microelements, sucrose, amino acids, and vitamins, and incubated in the dark at 25°C. Six months after sowing, 16 species from 9 genera germinated and continued development while 13 species from 10 genera failed to germinate. Species of Cypripedium, Goodyera, Platanthera and Spiranthes differed in response in that one or more of each germinated and one or more did not. Seedling development was similar for most germinating species and progressed to the formation of a shoot or shoot initial in all but one. Apparently the mycorrhizal association thought to be required for terrestrial orchid seed germination and early seedling development can be replaced with aseptic culture on a completely defined medium for many terrestrial orchids.

Effects of fungicides and bactericides on orchid seed germination and shoot tip cultures in vitro

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.

ランの無菌発芽培養基に関する研究

ランの無菌発芽培養基に関する研究

ランの無菌発芽培養基に関する研究 (第4報)

ランの無菌発芽培養基に関する研究 (第4報)

Observations on orchid seed mycorrhizae

In the natural germination of orchid seeds, the fungus undoubtedly contributes sugars, auxins, and growth factors in stimulating the growth of the embryo. However, none of these factors alone are as successful in stimulating germination as they are when combined. No single factor can be identified as the specific germination agent in the mycorrhizal relationship. Seeds can germinate, although poorly and slowly, without added sugars or auxins. Rather, a combination of factors promoting vigorous aerobic respiration provides the cellular environment necessary for germination. Fungus infection in nature, or artificial media in the lab, can provide these conditions: either rapidly by providing exogenous substrates and growth factors for respiration; or slowly by stimulating the utilization of endogenous lipid seed reserves. In either case, cell division and synthesis of chlorophyll follow. A speculatory metabolic pathway is outlined.

Factors affecting the germination of orchid seeds

THE Vol. BO T AN I C AL JANUARY-MARCH, REVIEW No. 1 FACTORS AFFECTING THE GERMINATION OF ORCH ID SEEDS 1 JOSEPH ARDITTI Department of Organismic Biology University of California Irvine, California 9266.f Introduction The orchid seed Orchid mycorrhiza and symbiosis Asymhiotic investigations Mineral nutrition _ .. _ Nitrogen nutrition .. The effects of sugars and other carbohydrates The effects of vitamins The effects of hormones . The effects of complex additives The effects of temperature The effects of light The effects of pH The effects of the atmosphere and its components The effects of moi sture The effects of miscellaneous factors . The nature of the factors required by germinating orchid seeds A note on the literature . Literature Cited ...... .. INTRODUCTION The Orchidaceae is one of che largest and most diverse of all plant families, consisting of 500- 800 genera and 20,000-30,000 species (Garay 1960, Schulces and Pease 1963). le is also among che masc widely distributed. Its representatives may be found from che Arctic to the Antarctic; in bogs, deserts, valleys, plains, hills, mountains, and even below ground (Hatch 195 3). Sizes of orchid planes vary from a few ( 3-4) mm. co several meters, whereas flowers may range from 2-3 mm. co 15-20 cm. or more in diameter. Some flowers are beauciful, e.g., Cattleya Lindi. and Phalaenop1i1 Blume, but 'Supported in pa rt by grants from the American Orchid Society, The Loeb Foundation, The Orchid Society of Southern California, and The Society of Sigma Xi.

Use of Tomato Juice in the Asymbiotic Germination of Orchid Seeds

1. Germination and growth data indicate that tomato-juice-agar solutions are more effective than the synthetic culture media containing only sugar and salts used generally for the asymbiotic germination of orchid seeds. These tomatojuice solutions are more strongly buffered in the pH range, 4.5-5.5, for good growth, even when the concentration of KH2PO4 in the synthetic solutions is increased from 0.025% to 0.6%; likewise the pH values in the good growth range are not altered by autoclaving. Apparently the availability of the iron compounds in the tomato-juice solutions is not affected by either autoclaving or continued growth. 2. Ashing of the tomato-juice solutions definitely indicates that organic rather than inorganic compounds are responsible for the enhanced growth. A protein hydrolysate, rich in amino acids and vitamins, added to the inorganic solutions, allowed more rapid growth than even the tomato-juice media. Concentrations of protein hydrolysate greater than 1%, however, are toxic to Cymbidium embryos. 3. In general, on organic culture media the protocorms fail to differentiate, only increasing in size. As the agar dries out, thus leaving a space between the agar and the flask, those protocorms not resting on the media but on the walls of the flask do differentiate, producing seedlings sturdier than those on solutions B and C, and hence lowering the mortality rate upon transplantation. When the enlarged undifferentiated protocorms are transplanted to osmunda fiber, differentiation occurs, and in 2 weeks sturdy seedlings begin to develop.

Some pH Changes in Nutrient Solutions

1. The culture media used generally for the asymbiotic germination of orchid seeds are so weakly buffered that, as the seedlings start to grow, the pH value drops below the level for optimum growth. Even when the phosphate buffer was increased twenty-four fold, the buffering action was still weak in the optimal growth range of pH 4.5-5.5, indicating that phosphate buffers are unsatisfactory. An investigation indicated that amino acids are excellent buffers. This work is being continued to determine what amino acids will be satisfactory not only as buffers but also as growth factors. 2. Autoclaving the culture media without agar produced significant changes in pH value. Similar changes in pH value were observed, only at a slower rate, when the solutions stood for some time. These results are equally applicable to ordinary nonsterilized culture media. The changes when the original pH value was 3 to 6 were due to the presence of iron sulfate, which should be replaced by one of the organic iron salts; when it...

Propagação de orquídeas por sementes

Knudson's asymbiotic method and medium for germination of orchid seeds were used with success. Heating this medium at 100°C twice for 15 minutes with an interval of 24 hours was found to be better than to sterilize just once at 120°C. This procedure avoids the hydrolysis of the agar. The poor quality of the glass from which some test tubes were made raised the pH tabove 5.9 and this was apparently the cause of poor developmen of the seedlings. Also some toxic elements given off by the glass diffusing thru the medium might havo impaired somewhat the results obtained in the experiment.

Sources of Carbohydrate for Germination and Growth of Orchid Seedlings

Ever since 1840, when Linck observed the endophytic fungus in orchid roots, the symbiotic relationship between these interesting plants has been studied by mycologists, plant physiologists, and horticulturists. We may roughly divide the research that has been done since 1840 into two main periods. The first period consisted in efforts to verify the universality of the endophytic infection and to link this mycorrhizal condition with various phenomena of germination. Wahrlich ('86) was the first to establish the generality of the occurrence of the endophyte. He examined the roots of five hundred species of orchids and found all to be contaminated with a fungus which he held to be species of Nectria. Since the time of Wahrlich, the taxonomy of the fungal symbiont has passed through a complex and varied evolution, but a discussion of this phase of orchid research is beyond the scope of the present paper. The existence of the endophyte was further verified by Prillieux ('56, '60), Prillieux and Riviere ('56), and by Fabre ('56). Bernard ('00) early suspected the relationship between the germination of orchid seeds and the presence of the endophyte. He obtained good germination on sawdust which was kept in the same greenhouse as the parent plants, and pointed out that this was probably due to an infection of the sawdust by the fungus from the parent plants. The publication of these results was followed by a number of other papers ('02, '03, '04, '06),

Flower Production by Orchid Grown Non-Symbiotically

In a number of papers previously published (6-9), issue has been taken with the view advanced by BERNARD (i), BURGEFF (3), and others that the orchid fungus is necessary for germination. In these various papers evidence was presented demonstrating that the germination of orchid seeds is dependent on an outside source of organic food. If a utilizable sugar is provided germination proceeds readily; if starch is provided there is no germination unless some means is provided for converting the starch into sugar. This may be accomplished by supplying the orchid fungus, or by the use of other fungi which will digest the starch and provide an appropriate hydrogen-ion concentration without at the same time growing so luxuriantly as to prevent growth of the orchid embryos. In the earlier papers the view was emphasized that the action of the orchid fungus is purely external, and therefore of no particular significance to the orchid embryo unless starch is available or other digestible food is supplied. It is not necessary here to summarize the evidence for the nonsymbiotic view. A recent paper (9) discussed the evidence for and against obligative symbiosis. The present paper is concerned primarily with the view held by some that obligative symbiosis is a requisite for flowering of the orchid plant. In a review of my first paper, COSTANTIN and MAGROU (5) intimated that seedlings produced by the non-symbiotic method would not flower. COSTANTIN (4) referred to this in a second paper, but later BULTEL (2) showed that plants produced from seedlings germinated asymbiotically would flower; and my results (g) were confirmatory. In the development of the orchid plants to the flowering stage, infection of the roots occurred both with BULTEL'S plants as

Non-Symbiotic Germination of Orchids

The propagation of orchids from seeds is a problem which has attracted the attention of many investigators. That orchids could be grown in the greenhouse from seeds was not considered extraordinary; orchid growers in Europe and in this country were successful in this line of work. Naturally scientists took up the study of the conditions of germination. In the roots of the orchid plants symbiotic fungi had been detected, and the first investigators of this problem, Bernard ('09) and Burgeff ('09) undertook experiments with the symbiotic fungus. Since they had no success without the fungus, the presence of the fungus was considered to be a conditio sine qua non. In 1922 Knudson published the results of his successful experiments on the nonsymbiotic germination of orchids, and a number of other investigators have worked on the same subject, in the majority of cases successfully. It is a well-known fact that a greater knowledge of the conditions for growing orchids is of particular interest not only to those working on the subject for commercial purposes, but also to those engaged in scientific investigations. From Knudson's ('25, '27) experiments we learn that the metabolic processes of the fungus bring about chemical changes in the medium which make it more assimilable. Chemical compounds indigestible for the seedlings are broken up or transformed into ones which can be easily used as food by the embryo. Another favorable influence of the fungus is the gradual acidification of the medium, according to Burgeff, Knudson, and Clement. However, experiments showed that it need not be necessarily the special orchid fungus. Other fungi may produce the same effect. Every one dealing with the germination of orchid seeds will have made the same discovery. From the experiments of Knudson and other investigators, such as Constantin and Magrou ('22), Ramsbottom ('22), and Clement ('24, '26, '29), our present knowledge of the requirements for successful germination of

Physiological Study of the Symbiotic Germination of Orchid Seeds

In two previous papers (6, 7) I have presented evidence that germination of orchid seeds is dependent upon an available supply of organic matter. These papers emphasized the nutritional aspects of the problem, and also presented certain views with respect to the possible function of the fungus in the pure culture experiments made by BERNARD (I), BURGEFF (4), and others. All who have studied the germination of orchid seeds agree that there is something very unusual about the seeds of most orchids, for they cannot germinate when merely supplied with water and nutrient salts. According to BERNARD, BURGEFF, IRAMSBOTTOM (ii), and CONSTANTIN and MAGROU (5), normal germination is dependent on infection of the embryo by the appropriate fungus. Symbiosis is believed by these men to be obligative for the normal development of orchids. Symbiosis in a broad sense means the living together of two dissimilar organisms. Under this definition, a very wide range of associations might be considered. The term as applied to the relation between the orchid and the orchid fungus includes the idea that the fungus is in some manner of benefit to the orchid plant, and, according to BERNARD, BURGEFF, and others, germination is normal-

Further Observations on Nonsymbiotic Germination of Orchid Seeds

In an earlier paper (5) on the nonsymbiotic germination of orchid seeds, a method was described for germinating seeds under pure culture conditions, and the successful germination of orchid seeds by the use of certain sugars was noted. The practical value of this method was indicated, and certain aspects of the problem respecting the relation of the fungus to germination were considered. It was suggested that germination is dependent upon a supply of organic substances. If the germinating orchid seed is dependent on an available supply of organic matter, then the method should be applicable to seeds of orchids other than those used in the previous experiments. The seeds successfully germinated by the use of sugar were those of Cattleya, Laelia, and Epidendron. No other seeds were available at that time. RAMSBOTTOM (7), reviewing this work of the writer, states that while the method may be useful in the germination of Cattleya and related forms, it will not prove successful for the seeds of Odontoglossum and related genera. He states, furthermore, that there is not much difficulty in germinating seeds of Cattleya, but the fact remains that under pure culture conditions Cattleya has not been germinated as yet in the absence of organic matter. Seeds of Cattleya and probably seeds of most orchids are unusual in that germination does not occur except when an outside source of carbon is available. In order to discover whether the method is applicable to other seeds, experiments were made with seeds of various genera, and that germination is possible is shown in the experiments here described. Certain other aspects of the problem are also considered. The methods used were essentially those previously described (5). Solution B or Pfeffer's solution was used throughout, although

Notes for Students

Previous articleNext article FreeCurrent LiteratureNotes for StudentsPDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by Volume 28, Number 3Sep., 1899 Article DOIhttps://doi.org/10.1086/327905 Views: 38 Citations: 2Citations are reported from Crossref Journal History This article was published in the Botanical Gazette (1876-1991), which is continued by International Journal of Plant Sciences (1992-present). PDF download Crossref reports the following articles citing this article:Tim Wing Yam, Joseph Arditti History of orchid propagation: a mirror of the history of biotechnology, Plant Biotechnology Reports 3, no.11 (Jan 2009): 1–56.https://doi.org/10.1007/s11816-008-0066-3Joseph Arditti Factors affecting the germination of orchid seeds, The Botanical Review 33, no.11 (Jan 1967): 1–97.https://doi.org/10.1007/BF02858656