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Volume 4 Special Issue 1, 2010
Focus on Orchids
ISBN 978-4-903313-52-8
How to reference: Lönnig W-E (2010) Mutagenesis in Physalis pubescens L. ssp. floridana: Some Further Research on Dollo’s Law and the Law of Recurrent Variation. In: Focus on orchids. Floriculture and Ornamental Biotechnology 4 (Special Issue 1), 1-21
CONTENTS AND ABSTRACTS
Wolf-Ekkehard Lönnig (F. R. Germany) Mutagenesis in Physalis pubescens L. ssp. floridana: Some Further Research on Dollo’s Law and the Law of Recurrent Variation (pp 1-21)
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ABSTRACT
Original Research Paper: In a mutagenesis programme 240,000 Physalis plants have been investigated to further test Dollo’s law and the law of recurrent variation during the last few years (2005-2008), including 10,000 M1 plants and 8,600 M2 families. In contrast to the predictions of Dollo’s law, that "an organism cannot return, even partially, to a former state already realized in the series of its ancestors" (or, more generally that evolution is "irreversible"), in several mutants the inflated calyx syndrome (ICS, also known as "Chinese lantern") did, indeed, partially revert into the direction of normal sepals after fertilization, at least phenotypically. Also, in several individual cases the ICS proved to be even so strongly reduced that hardly anything of the former typical lantern structures could be identified. However, in line with Dollo’s law so far, all these starkly pronounced cases turned out to be only modifications and thus could not be obtained as a distinct revertant character in a pure mutant line. Moreover, polyphyly vs. monophyly of the ICS is extensively discussed considering the different current views on the origin of species. In agreement with the predictions of another biologic law, the law of recurrent variation, a significant range of virtually identical phenotypes (including an imposing number of mutants with reduced lanterns) reappeared time and again – i.e. independently of each other – in many M2 families, but no indications for the origin of a new systematic species (not to bring up the rise of a primary species) have been found in the range of mutants, which were probably all due to losses-of-function mutations. As to saturation mutagenesis, a plateau concerning different phenotypes may almost have been reached for some features as perhaps leaf margin structure, but certainly not yet for other characters including the ICS. Moreover, after briefly referring to some points in the introduction, several clarifications concerning (and objections against) the law of recurrent variation are addressed in the Discussion including the applicability of the term "law" and its relevance in biology in general as well as the principle of the "Unendlichkeit im Kleinen", that is microevolutionary infinity.
Madhumita Majumder, Sudhanshu S. Maiti, Nirmalya Banerjee (India) Direct and Callus-mediated Protocorm-like Body Induction and High Frequency Adventitious Shoot Regeneration in an Endangered Orchid – Dendrobium farmeri Paxt. (Orchidaceae) (pp 22-28)
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ABSTRACT
Original Research Paper: A rapid and reliable micropropagation method was developed for Dendrobium farmeri Paxt. using shoot-tip culture system. Shoot-tip explants were excised from aseptically raised 3-month old seedlings and were cultured on modified Knudson’s C nutrient solution supplemented with different concentrations of α-naphthaleneacetic acid (NAA) and thidiazurone (TDZ) in factorial combinations. After 3-4 weeks of culture, both direct as well as callus mediated protocorm-like body (PLB) formation from the basal cut ends of explants were observed. Optimum frequency of callusing (51.28%) was recorded in the presence of 2 µM each of TDZ and NAA. Following transfer to PGR-free medium, the callus exhibited vigorous growth and regeneration of PLBs and was maintained for more than 1 year without any loss of embryogenic potential. TDZ at higher concentrations showed an inhibitory effect on callus-mediated PLB formation and caused the extensive necrosis of callus. For direct initiation of PLBs, maximum frequency (61.90%) was found at 1 µM TDZ, yielding 13 PLBs/explant. These direct as well as callus-mediated PLBs readily germinated into well rooted plantlets. The explants that failed to respond to both callus induction and direct PLB formation media generated proliferating shoot buds which ultimately produced healthy adventitious shoots with several branches. The optimal combination for maximum shoot regeneration (69.22%) was 1 µM each of TDZ and NAA, giving rise to 1.89 shoots/explant. Rooted plantlets were readily acclimatized to greenhouse condition and a preliminary planting trial of the plantlets in the natural habitat resulted in 60% survival rate.
Paveena Kaewubon, Supinya Sangdam, Kanchit Thammasiri, Upatham Meesawat (Thailand) Plant Regeneration through Somatic Embryogenesis from Callus-derived PLBs ofTropical Slipper Orchid (Paphiopedilum niveum (Rchb.f.) Pfitz.) (pp 29-35)
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Original Research Paper: We have developed a protocol for the indirect production of protocorm-like bodies (PLBs) from germinating seeds and subsequently regenerated plants of a slipper orchid (Paphiopedilum niveum (Rchb.f) Pfitz.). To solve the serious problem of necrosis that occurs during normal culture and the subsequent stages of development, the incorporation of activated charcoal (AC) and polyvinylpolypyrrolidone (PVPP) into the culture media during the stage of callus induction was also examined. Embryogenic callus was induced from the germinating seeds and showed no browning or only a few necrotic tissues on modified Vacin and Went (VW) solid medium supplemented with 0.1 mgl-1 1-phenyl-3-(1,2,3-thiadianol-5-yl) urea (thidiazuron) (TDZ), 1 mgl-1 2,4-dichlorophenoxyacetic acid (2,4-D) and 0.2% AC. These calli developed further along the route for production of PLBs on modified VW medium containing a combination of plant growth regulators (0.1 mgl-1 1-napthaleneacetic acid (NAA) and 0.5 mgl-1 TDZ) and 1% sucrose. The regenerated PLBs eventually formed the highest number of shoots and roots on modified Murashige and Skoog (MS) solid medium supplemented with 20 and 50 gl-1 banana homogenate, respectively. About 90 regenerated shoots were obtained from about 10 mg of initial PLBs. Samples of the obtained plantlets grew well after being transplanted into mini-pots placed in a shaded greenhouse. A histological study showed that PLBs originated from the surface of the embryogenic callus. Some PLBs could produce secondary PLB resulting in greater PLB proliferation. The PLB-derived plantlets had shoot and root poles indicating that plant regeneration could be considered as a pathway for somatic embryogenesis.
Pritam Chattopadhyay, Nirmalya Banerjee, Bhupendra Chaudhary (India) Precise Seed Micromorphometric Markers as a Tool for Comparative Phylogeny of Dendrobium (Orchidaceae) (pp 36-44)
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Original Research Paper: Orchid seeds are microscopic in nature and have been widely used in defining phylogenetic relationship among different genera. The genus Dendrobium is the second largest in the family Orchidaceae. The present study aims at evaluation of seed micromorphology of Dendrobium in the light of recent phylogenetic studies and to test whether the seed micromorphology strictly reflects the phylogenetic relationships at the inter-specific level. The seeds from 18 different Dendrobium species collected from throughout the Indian continent representing different sections were directly measured for six scorable micromorphometric traits (variables) through multivariate analysis and investigated for deducing their phylogenetic relationship. Concurrently seed sculpturing was also investigated from different populations of a particular species to normalize potential intra-specific variations using scanning electron microscopy. A reference phylogenetic tree from the ribosomal ITS 2 sequences was also constructed as a standard reference reflecting a DNA-based phylogenetic relationship among all species studied. Seed, embryo and testa cell length and width were six major quantitative variables observed to be important in deducing inter-specific phylogeny exhibiting congruence with ITS2-based phylogeny. However, seed coat sculpturing has not been observed in congruence with phylogeny; rather, they may be involved in ecology of the particular species.
Pham Thanh Van, Michio Tanaka, Jaime A. Teixeira da Silva (Japan) Gelling Agent Affects Hybrid Cymbidium Plantlet Growth (pp 45-47)
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Short Communication: The choice of gelling agent impacted the growth and development of hybrid Cymbidium Maria ‘Music Hour’. Gellan gum resulted, in general, in better plant growth parameters than liquid medium, Bacto agar and oatmeal agar. The number of roots was highest on Gellan gum as was the fresh and dry mass of shoots and roots although more leaves were produced on Bacto agar. These results point towards the need to test the agar source prior to growth of hybrid Cymbidium plantlets, since this medium substrate can strongly affect the outcome of an experiment.
Marcos Ribeiro da Silva Vieira (Brazil), Jaime A. Teixeira da Silva (Japan), Giuseppina Pace Pereira Lima (Brazil), Fabio Vianello (Italy) Changes in Polyamine, Total Protein and Total Carbohydrate Content and Peroxidase Activity during the Lifetime of Chrysanthemum ‘Faroe’ (pp 48-52)
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Original Research Paper: The aim of the present work was to evaluate the changes in polyamine (PA) content, peroxidase (POX) activity and levels of total protein and total soluble carbohydrates throughout the lifetime of leaves and inflorescences of chrysanthemum ‘Faroe’ treated with gibberellic acid (GA3) (used in production practices) and kept at room temperature and cold storage. The treatments were composed of four doses of GA3 (0, 15, 30 and 45 mg L-1) applied at the beginning of flower bud formation (28 days after transplanting of seedlings). After harvesting, the stems (95% of the expanded ligule) were stored at 10°C and 95% relative humidity for 48 hrs, or kept at room temperature. For biochemical analysis samples of leaves and inflorescences were collected at the 4th, 8th, 12th and 16th day after harvest. The application of GA3 in the field and cold storage increased the content of PAs. There was an increase in POX activity in leaves and inflorescences during postharvest and this increase was related to oxidation of the PAs studied. The amount of proteins and carbohydrates in chrysanthemum ‘Faroe’ decreased during storage at 25°C and under cold conditions.
Kit D. Jernshøj, Søren Hassing, Carl-Otto Ottosen (Denmark) Non-destructive Determination of Chlorophyll Concentration in the Leaves, Sepals and Bracts of Hibiscus rosa-sinensis and Leaves of Chrysanthemum × morifolium (pp 53-62)
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Original Research Paper: An analysis of the composition and concentration of pigments – both chlorophyll (Chl) and other protective pigments, is often critical, when analyzing the reaction of plants to the effects of abiotic conditions. Therefore, a rapid non-destructive method for determining pigment concentrations accurately would be an advantage. The chlorophyll (Chl) concentrations in the leaves, sepals and bracts from Hibiscus rosa-sinensis and the leaves from Chrysanthemum × morifolium were determined in vivo by applying two different algorithms to the reflectance and transmittance data obtained from a spectrophotometer with an integrating sphere. As sepals and bracts from Hibiscus are small, a modification was needed using a mask. When measuring reflectance, a mask has been combined with a properly focused sample beam, to avoid direct illumination of the mask. The transmittance spectra are achieved by a combination of a lens setup and an attachment of the sample to the entrance port. Two different models have been used for the calculation of Chlorophyll concentration. The first model is based on an empirical relationship between reciprocal reflectance and Chl concentration, whereas the second model is based on the optical characteristics of the leaf. Our aim with the experiments was to improve the methods for non-invasive detection of Chl in ornamental plant species and leaf types.
Sasan Aliniaeifard, Seid Jalal Tabatabaei (Iran) Use of Chlorophyll Meter for Nitrogen Management and Recommendation of Optimum Nitrogen Concentration in Soilless Culture of Lily (pp 63-67)
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Original Research Paper: Nitrogen (N) is one of the most important essential elements that affects plant growth and has the highest concentration among mineral elements; a shortage of N causes more adverse effects than other mineral elements. To achieve optimum N concentration in nutrient solution through the use of a chlorophyll meter in the soilless culture of lily, four N concentrations (100, 200, 300, 400 mg L-1) were applied to lily (Lilium longiflorum) cv. ‘Pink perfection’. Chlorophyll index and leaf number increased as N concentration increased. The increase in leaf number was gradual. Higher concentrations of N in nutrient solution induced an increase in shoot length. The chlorophyll meter is a simple way to monitor N concentration at different stages of lily growth.
Abhay Kumar, M. N. V. Prasad (India) Propagation of Talinum cuneifolium L. (Portulacaceae), an Ornamental Plant and Leafy Vegetable, by Stem Cuttings (pp 68-71)
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Original Research Paper: This paper reports on the propagation of Talinum cuneifolium through stem cuttings. It is popularly known as Ceylon spinach and is used as a leafy vegetable in the tropics. In the present study, stem cuttings of T. cuneifolium were successfully propagated in soil and hydroponic media. Propagated plants flowered extensively within a week under both conditions. Stem cuttings of plants in hydroponic media initiated adventitious roots within a week. The growth and development of vegetative propagules, flowers and adventitious roots were determined at different periods of the experiment. Our study indicated that T. cuneifolium can be propagated through stem cutting within 7-days of culturing. Furthermore, hydroponically grown shoots with adventitious roots can serve as an ideal experimental system for toxicity bioassays (rhizofiltration) in the field of environmental research.
Arvinder Singh, Nomita Laishram (India) Drying of Flowers and Other Ornamental Plant Parts in India (pp 72-78)
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Mini-Review: With the increasing awareness for natural ecofriendly products, dried flowers have attained prime importance in the floriculture industry. Future prospects of the dry flower industry are expected to contribute a lot to the country’s economy in comparison to the fresh cut flowers and other live plants. Dry flowers and plant materials have tremendous potential as substitute for fresh flowers and foliage for interior decoration as well as for a variety of other aesthetic and commercial uses. In this review the scattered information and data on drying of flowers and other ornamental plant parts are being tried to put together. This could eventually be helpful in drawing the attention of the researchers and scientists to work on it, besides the entrepreneurs would be directly benefitted by utilizing the knowledge review in this paper.
Sunita Chandel (India), Jaime A. Teixeira da Silva (Japan), Chhaya Sharma (India) Management of Alternaria Leaf Spot and Flower Blight of Marigold (Tagetes erecta L.) cv. ‘Crackerjack’ by Applications of Fungicides and Neem Formulation (pp 79-83)
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Original Research Paper: Marigold (Tagetes erecta L.) cv. ‘Crackerjack’ is an important commercial ornamental pot and garden flower. Alternaria zinniae, the cause of leaf spot and flower blight, and which are seed- and air-borne in nature, are the major constraints in marigold cultivation. Seed treatment studies using 8 fungicides (mancozeb, foltaf, copper oxychloride, captan, zineb, chlorothalonil and thiram) and a neem formulation, neemicidin, were carried out against A. zinniae. All chemicals were effective although higher doses of some fungicides had an adverse effect on seed germination. Mancozeb and chlorothalonil effectively reduced the seed-borne infection in marigold with no adverse effect on seed germination even if applied in slightly higher doses (3.5 and 5.0 g/kg). In a field trial, mancozeb performed better than other chemicals by reducing the disease severity of leaf spot recorded in the control from 65.81 to 3.13% and with no incidence of flower blight even after 60 days. Captan and chlorothaonil were the next effective fungicides in management of the disease.
Neda Jalali, Rouhangiz Naderi (Iran), Jaime A. Teixeira da Silva (Japan), Mesbah Babalar, Masoud Mirmasoumi (Iran) Influence of Salt Concentration of Media and Plant Growth Regulator Combination on Callus Formation and Somatic Embryogenesis of Cyclamen persicum Mill. (pp 84-87)
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Original Research Paper: Cyclamen persicum Mill. (Primulaceae) is an important ornamental crop sold worldwide as pot flower for winter production. It is commercially propagated via seeds. Somatic embryogenesis which is an important requirement for breeding material and mass propagation, was induced through a callus phase from young leaf explants of an ex vitro mother plant. Somatic embryos were cultured on modified Murashige and Skoog (MS) medium to test the effect of half and full salt concentrations. In addition, embryogenic callus was induced on several media containing 2,4-dichlorophenoxyacetic acid (2,4-D) and kinetin. Maximum somatic embryogenesis was possible on ½ MS medium containing 4 mg l-1 2,4-D and 0.1 mg l-1 kinetin.
Changxin He, Binxuan Wu, Guohua Ma (China) TDZ-induced Callus and Adventitious Shoot Formation from Leaf, Petiole and Calyx Explants of Tigridiopalma magnifica (Chen) (pp 88-91)
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Short Communication: Tigridiopalma magnifica Chen is an endemic, critically endangered species found only in Guangdong Province, China. Unfortunately, economic exploitation has impacted severely on its natural environments in mountain areas in recent years, disrupting fragile plant communities and sharply decreasing distribution of the species. To better protect but also allow sustainable utilization of this critically endangered ornamental plant, we report on an efficient in vitro mass propagation and plant regenerationprotocol from original in vivo explants. Callus and adventitious shoot formation was induced on calyx explants incubated on induction media (Murashige and Skoog) containing thidiazuron (TDZ) alone or in combination with 6-benzyladenine (BAP). Leaf and petiole explants from in vitro grown plants also induced callus and adventitious shoot formation on induction media containing 4.4-22.0 µM TDZ alone or in combination with 2.25 µM BAP or 5.37 µM α-napthaleneacetic acid (NAA), respectively. Our study shows that TDZ plays a crucial role in the induction of adventitious shoots from calyx, leaf and petiole explants. Once adventitious shoots were induced, shoots were able to be propagated and subcultured for mass proliferation on MS media containing 1.07 µM NAA and 4.45 µM BAP or 1.07 µM NAA and 4.6 µM cytokinin, respectively. Root formation was achieved on ½MS medium containing 0.49-4.92 µM 3-indolebutyric acid or 0.54-5.37 µM NAA; 99% of rooted plants survived establishment in soil.
Geetika Gambhir, Surinder Kumar, Shweta Sen (India) An Improved Regeneration System of Oriental Lily Hybrid from Ovary-Ovule Culture Using Plant Growth Regulators (pp 92-95)
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Research Note: The influence of plant growth regulators (PGRs) on bulblet regeneration from oriental hybrid lily ‘Casa Blanca’ ovary tissues was investigated. Pistils excised from unopened flower buds (5-8 cm long) were sectioned and cultured on Murashige and Skoog (MS) medium supplemented with different concentrations of PGRs singly, or in combination. Bulblets were initiated on MS medium supplemented with 0.5 mg L-1 6-benzyladenine (BA) or with 1.5 and 2 mg L-1 zeatin (Zea). The number of bulblets per explant and average fresh weight per bulblet were highest with 2 mg L-1 α-naphthaleneacetic acid (NAA) and 1.5 mg L-1 BA, whereas bulblet regeneration response varied with PGR treatment. Bulblets rooted with 0.5 mg L-1 NAA and were transferred to plastic pots containing cocopeat for hardening. Chromosome observations revealed that all regenerated bulblets tested were diploid (2n = 24).
K. Roy, H. K. Sarkar, A. Pramanik (India) Morpho-anatomical Changes in Gladiolus due to Infection by Aphelenchoides besseyi from West Bengal, India (pp 96-98)
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Research Note: A critical study on the morpho-anatomical changes in the leaves of Gladiolus sp. consequent to infection by Aphelenchoides besseyi Christie, a nematode, was carried out. Gladiolus sp. cv. ‘Red Majesty’ was found naturally infected by A. besseyi during January, 2009 at the University Central Research Farm, West Bengal, India. Elongated, vein-bounded, light brown to deep brown streaks developed on the leaf and progressed both ways but never reached the leaf tips. Streaks become necrotic and black, subsequently dried up gradually. A huge number of nematodes was isolated from the infected leaves of Gladiolus; they were identified as A. besseyi. Morpho-anatomical changes of the foliar nematode-infected leaves comprised of disintegrations of epidermal tissues followed by formation of vacuoles of diverse shapes and sizes. Stomata as well as disintegrated epidermal tissues might be a suitable route for A. besseyi to gain access into the internal leaf tissues of Gladiolus. The present finding of foliar nematode infection through stomata and disintegrated epidermal tissues may be helpful in disease management of Gladiolus.
Haiyun Wang, Songlin He (China), Michio Tanaka, Pham Thanh Van, Jaime A. Teixeira da Silva (Japan) Effects of 2,4-D on Callus Formation in Tree Peony (Paeonia suffruticosa Andr.) under Different Light Conditions (pp 99-102)
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Research Note: Petioles and leaves of three-month-old in vitro tree peony (Paeonia suffruticosa Andr. cv. ‘Wu Long Peng Sheng’) plantlets were used as explants for callus induction. The effects of different concentrations of 2,4-dichlorophenoxyacetic acid (2,4-D) and different light sources and quality were investigated. If no 2,4-D was present in the medium, then no callus formed. To induce maximum callus formation from tree peony, either 1 mg L-1 2,4-D using petiole explants under red or blue cold cathode fluorescent lamps, or the same concentration of 2,4-D using leaf explants in the dark, was required. |
