Medium For Seed Germination Research Articles

In vitro asymbiotic propagation of the vulnerable slipper orchid Cypripedium cordigerum D. Don

This paper presents an attempt to establish a protocol for the conservation of Cypripedium cordigerum D. Don a vulnerable species of orchid using in vitro symbiotic seed germination. The suitability of four orchids seed germination media [Terrestrial orchid medium (BM), modified terrestrial orchid seed germination medium (BM-1), Malmgren modified terrestrial orchid medium (MM), Knudson C medium (KC)] was tested using different photoperiods i.e. 24-h dark or 12-h light per day. The seed capsules were harvested at two different stages of development in order to determine the effect of capsule maturity on seed germination. The maximum percentage germination of seed from intact capsules in the dark was 65.00 ± 0.12% on the BM-1 medium. Release of brownish exudates was stopped by the addition of activated charcoal to the cultures. Seedlings developed in 26.17 ± 0.17 weeks. The current study is the first to report the ex-situ conservation of C. cordigerum.

A predictive method for selecting the most appropriate level of water potential for Thymus daenensis ssp. daenensis Cleak seed priming with respect to the severity of salinity or drought stress

Thymus daenensis ssp. daenensis Cleak is an aromatic medicinal plant belonging to Lamiaceae family. Seed priming is a practical method to alleviate salinity and drought stress over germination stage. The objective of this study was to determine the most appropriate water potential level of seed priming solution according to the level of the salinity or drought stress of the medium which T. daenensis seeds will be sown. A factorial completely randomized design with four replications was conducted, one for salinity stress by using NaCl and another for drought stress by using PEG 6000. The first factorial design consisted of five seed medium water potential levels including 0, − 0.3, − 0.6, − 0.9 and − 1.2 MPa and the second was six seed priming treatments, including unprimed (UP), hydroprimed (HP, 0 MPa), − 0.3, − 0.6, − 0.9 and − 1.2 MPa water potential solutions. Priming efficacy (PE) is suggested in this study as a new characteristic for evaluation of the efficiency of priming. The PE values revealed that priming increases the germination percentage in all treatments; based on the obtained values of PE, the most effective priming treatment was the hydropriming in − 9 MPa of PEG. The final percentage germination (FPG), germination speed (GS), and root and shoot length (RL and SL) were reduced by decreasing the water potential levels of NaCl and PEG iso-osmotic solutions at 0, − 0.3, − 0.6, − 0.9 and − 1.2 MPa. All the traits were higher in NaCl than in PEG at the same water potential. Priming was helpful in overcoming the negative effects imposed by reduced water potential upon seed germination. The severity of salinity or drought stress determined the level of water potential would be better suited for seed priming. The highest germination percentage for the seed medium with Ψ-0.3 and Ψ-0.9 solutions was achieved by the priming solution of − 0.9 (96%) and − 0.3 (56%) MPa for NaCl treatments, respectively; and − 0.6 (94%) and 0 (35%) MPa for PEG treatments. There were second or third-order polynomial relationships between water potentials in seed germination medium and priming solutions according to the germination characteristics. Consequently, predictive equations were derived for each characteristic to show the suitable priming treatment regarding to the seed germination water stress level. The results showed that higher water potential treatments should be chosen for priming if germination is expected to occur under lower water potential and vice versa. This achievement can be used in rehabilitation of the degraded lands of T. daenensis by seed dispersal or when irrigating with saline water is required under cultivated fields.

Asymbiotic in vitro seed germination, in vitro seedling development, and ex vitro acclimatization of Spiranthes.

PremiseReproducible seed propagation and production protocols were developed for Spiranthes and related taxa to facilitate ex situ conservation practices.Methods and Results Spiranthes seeds were scarified for 3‐ and 10‐min intervals in 10% sodium hypochlorite solution, then cultured on three seed germination media. After germination, seedlings were given one of the three photoperiod treatments, and then planted in one of four greenhouse substrates. Seed germination ranged from 0% to 90% and occurred on all three media only after the 3‐min scarification. Seedlings in the 24/0‐h light/dark and 16/8‐h light/dark photoperiods on P723 medium had significantly higher fresh weight than those in the dark treatment group. Ex vitro survival ranged from 55% to 95% across substrates.ConclusionsResults show that Spiranthes seeds are damaged by extended chemical scarification, are adaptable to a variety of culture media, and require light for optimal development. Further experimentation showed that the propagation protocols described here can be applied broadly within the genus.

The analysis of germination of two types of <em>Momordica charantia </em>L. seeds in different media after different storage durations

Momordica charantia L. is a member of Cucurbitaceae can be use as rootstock for obtain seedlings againsts some abiotic and biotic stress factors. For these reasons, the aim of this study was to evaluate effect of origin of the plant types, germination media and seed storage duration on seed germination and seedling rates. The two different plant types (A and B) belonging to non-commercial gardens from two different districts located 30 km from each other in Kocaeli City were tested in 3 seed germination media (paper towel, petri dishes and sand) after 0, 90, 180 and 270 days storage under dark-room condition. First and last germination days, first and last leaf appearance days, germination and seedling rate were monitored. The study designed as Completely Randomized Design replicated thrice and after statistical analyzes, analysis of variance with Duncan Multiple Range Test method at P˂0.05 was performed. Considering the whole experiment first germination days changed between 4th-5.7th and last germination days changed between 4th-13.7th days. There is no difference between the plant types in the parameter at all the three media. Maximum germination and seedling ratio were observed at type-A in the all media. In petri, the germination and seedling ratio parameter decreased gradually with storage duration although storage duration showed no differences in paper towel or sand in the germination and seedling parameters. Optimum seedling ratio of Momordica charantia was observed when sand media were used at ratio of 99.2% in type-A and 88.35% in type-B in averages at all the storage durations under the study condition.

Uticaj pred tretmana na semenu i temperature u klijalištu na klijavost četiri partija semena Festuloliuma

A species called Festulolium was created in the middle of the last century by crossing two genuses: Lolium and Festuca. This was followed by a period of research on Festulolium from the aspect of genetics and breeding, seed production, cultivation, technology and use. We conducted various pre-treatment impact studies on Festulolium seeds: i) cooling at 5-7 o C for 3 days, ii) application of KNO3 on seed germination medium, and the third pre-treatment was control, without pre-treatment (iii). After pre-treatment (i, ii, iii), seed germination have examined at the following temperature regimes (provided by the seed quality regulations): 20 o C (dark); alternately 20o C/ 30o C (light /dark); and 30 o C (dark). The tests were performed on four seed lots of the variety Peron, in four replicates. The germination temperature of 30 o C reduced germination and increased dead seed and abnormal germination in all pre-treatments. The variant without the application of pre-treatment had a significantly lower overall germination in the assessment of Festulolium seed quality. Seed lots showed a high influence on the Festulolium seed quality.

Asymbiotic seed germination and in vitro seedling development of Pelatantheria scolopendrifolia, a rare epiphytic orchid native to Korea

Pelatantheria scolopendrifolia (Makino) Aver. is a critically endangered orchid species. In this study, an asymbiotic seed germination and development protocol to facilitate in situ and ex situ conservation of P. scolopendrifolia was determined. Seedlings were cultured in vitro on 1/2-strength Murashige & Skoog medium (1/2 MS), Phytamax Orchid Maintenance Medium (POM), Orchid BM1 Terrestrial Seed Germination & Stem Propagation Medium (OBTSG), or Orchid BM2 Terrestrial Stem propagation and Callus Medium (OBTSCM). Seeds started to germinate on all media except POM, with optimal growth on 1/2 MS medium, wherein 70% of seed germinated and produced roots and shoots within 12 weeks. Thus, we recommend culturing P. scolopendrifolia Seeds on 1/2 MS to facilitate germination and seed development, and in turn, in situ and ex situ conservation of this endangered species.

The Vigor and Viability Seed Testing of Three Tobacco Varieties on Various Seed Germination Media

Seed viability is one of the most important physiological quality benchmarks of seeds. The use of appropriate germination media can affect the results of seed viability testing. This study aims to determine the optimal germination media in tobacco seed viability testing. This research was conducted at the Seed Laboratory of the Indonesian Sweetener and Fiber Crops Research Institute, Malang in January - March 2019. The research method used a two-factorial randomized block design (RAK). The first factor is tobacco seed varieties consisting of Kasturi in 2007, Bojonegoro in 2012 and Kemloko in 2014. The second factor is the seed germination media consisting of straw paper, cotton, towel tissue, paperboard and newspaper. The results showed that the Kemloko variety of tobacco seeds germinated in the towel tissue had the best seed vigor and viability percentage. Seed germination media with paperboard, towel tissue and straw paper can be used to test the viability of tobacco seeds because they have a percentage of simultaneous growth, percentage of the growth speed, percentage of germination, percentage of the growth potential maximum and normal seedling dry weight which are equally well

Propagation of Dendrobium antennatum Lindl via Seed Culture In Vitro Using Simple Medium: Fertilizer and Complex Organic Based Medium

A New Guinea Orchid, Dendrobium antennatum Lindl urgently needs to conserve. The availability of in vitro germination technique for this orchids is significantly important to present the useful tool for conservation effort. This study aimed to find a simple media that consists of Growmore 10-55-10, a foliar fertilizer and complex organic i.e. coconut water, banana pulp, onion spring extract, and carrot juice. Five in vitro medium for seed germination and four in vitro sub-culture medium for planlet growth were formulated and used in this study. Our findings revealed that seed germination in vitro of Dendrobium antennatum well occured on the medium of Growmore 10-55-10 supplemented with 10% coconut water (GCw) and of Growmore 10-55-10 supplemented with 50 g/l extract spring onion. The seed germination process from sowing the seed to plantlet production ready to transfer to sub-culture medium for further growth took time 140 days. The embryo became pale green at the day 11 on the germination media. It could be used as a tool for detection of viability of the seeds. Both seed germination medium could be used also as sub-culture medium for enhancing the growth of the plantlets but not for multiplication of shoots.

Optimization of in vitro asymbiotic seed germination protocol for Serapias vomeracea

Abstract Serapias vomeracea is an economically important orchid species which is over-collected from nature, because of its glucomannan-rich tubers. Thus, optimization of in vitro culture methodology in this species is required to meet industrial needs and to secure its populations in nature. This study aimed to optimize the surface sterilization protocol for S. vomeracea seeds and to select the optimal seed germination medium by comparing the commonly used media in in vitro orchid culture. During seed surface sterilization, ethyl alcohol (EtOH) pre-treatment prior to sodium hypochlorite (NaOCl) treatment increased the disinfection success and viable seed yield when examined using the triphenyl tetrazolium chloride (TTC) seed viability test. Also, low-g force centrifugation as an additional step in the surface sterilization method separated the seeds without embryo from the viable seeds and thereby decreased potential counting errors after incubation. Comparison of media showed that solid Knudson C (KN) medium induced the highest number of germinated seeds. However, seed germination success of Lindemann (LN) and Vacin & Went (VW) media was found to be higher when the media was used in liquid form. Half-strength liquid VW was the only medium that induced higher germination success than the other full-strength media. The highest number of ungerminated seeds was found when using KN medium whereas liquid VW medium gave the lowest number. In general, protocorm formation was triggered when the media were used in liquid form. However, rhizoid elongation was suppressed in liquid media. These findings suggest that this optimized seed surface sterilization method offers a simple and effective alternative to classical methods. Additionally, solid KN medium may be considered as a cost-effective and reliable alternative to other commonly-used complex media in S. vomeracea cultures.

Establishment and Optimization of Wild Beltilla striata Regeneration System

We used the ripe capsules from wild Bletilla striata as explants to establish regeneration system. The optimal medium for seed germination was 1 /2MS + 6-BA 1. 0 mg·L- 1+ NAA 0. 1 mg·L- 1+ AC 0. 5 g·L- 1.The most suitable medium for PLB multiplication was MS + KT 1. 0 mg·L- 1+ NAA 0. 1 mg·L- 1+ AC 0. 5 g·L- 1,while MS + 6-BA 0. 5 mg·L- 1+ KT 1. 0 mg·L- 1+ NAA 0. 1mg·L- 1+ AC 0. 5 g·L- 1was appropriate for PLB differentiation. The optimal medium for adventitious buds multiplication was MS + 6-BA 0. 5 mg·L- 1+KT 1. 0 mg·L- 1+ NAA 0. 1 mg·L- 1+ AC 0. 5 g·L- 1+ potato juice 150 g·L- 1,and the proliferation rate was up to 343% after 30 days. The most suitable rooting medium was 1 /2MS + IBA 0. 5 mg·L- 1+ AC 0. 5g·L- 1+ potato juice 100 g·L- 1with the rooting rate of 100%. The best way of tube seedlings transplanting was under the volume ratio of sphagna: batk: Coconut chaff: wood flour of 2∶2∶1∶1 with 99% of survival rate.

Effects of explant age, germination medium, pre-culture parameters, inoculation medium, pH, washing medium, and selection regime on Agrobacterium-mediated transformation of tomato

An efficient protocol was developed for Agrobacterium tumefaciens-mediated transformation of tomato (Solanum lycopersicum) cultivars using cotyledon explants. The transformation frequency was assessed in response to several different factors, including seed germination medium, seedling age, pre-culture duration, pre-culture and co-cultivation media, inoculation medium, medium pH, washing medium, and kanamycin concentration in initial selection medium. Cotyledons excised from 6-d-old seedlings germinated on half-strength Murashige and Skoog’s (MS) basal medium containing 8.9 μM benzyladenine (BA) produced the most suitable explant material. Six days of explant pre-culture and 5 min inoculation with Agrobacterium culture in MS medium, containing 8.9 μM BA, 9.3 μM kinetin, and 0.4 mg l−1 thiamine at pH 5.0, significantly improved the transformation frequency. The addition of a tobacco feeder cell layer, however, did not lead to any significant improvement in the transformation rate. Kanamycin at 20 mg l−1 in the selection medium for the initial 10 d resulted in the highest transformation frequency. Combining the best conditions for each parameter resulted in an overall transformation efficiency of 44.3 %. Gene transfer was confirmed through PCR and Southern blot analyses. Mendelian inheritance ratios were found in 71.5 % of the independent transgenic lines from self-fertilized T1 progeny. The optimized transformation procedure showed high transformation frequencies for all three tomato cultivars tested, namely, Kashi Vishesh (H-86), Hisar Anmol (H-24), and Kashi Amrit (DVRT-1), and is also expected to give reproducible results with other tomato cultivars.

Lentil Regeneration from Cotyledon Explant Bearing a Small Part of the Embryo Axis

The effect of external BAP on explants including leaflets, stems, cotyledons with and without embryo axis of lentil (Lens culinaris Medic.) were tested on the frequency of shoot induction. The effect of different levels and combinations of various cytokinins on multiple shoot induction and elongation of shoots were compared. The effect of explant age and pH of media were also tested on shoot induction from various explants. Finally, the effect of IBA, IAA, and NAA on root induction of elongated shoots were examined. Optimum conditions for root emergence and growth and the hardening of seedlings were determined. Cotyledon with small part of the embryo axis was the superior explant. Shoot induction from the explants was enhanced by inclusion of BAP in the seed germination medium. The highest shoot induction (up to 96%) was obtained on MS with 7.5 µM 2-ip, 4 µM kn, and 2 µM TDZ. Over 80% of the elongated shoots produced roots in solid 1/4 BS media with 50 µM NAA for 3 days followed by 10 days in a mixture of liquid 1/4 BS, vermiculite and sand. Root development and hardening of the seedlings was achieved by using a hydroponics system containing Arnon’s solution. Tissue culture derived plants were transplanted to the greenhouse where the seeds were harvested after about 4 months. Key words: regeneration, Cotyledon, Embryo axis, Lentil, Lens culinaris D. O. I. 10.3329/ptcb.v21i2.10240 Plant Tissue Cult. & Biotech. 21(2): 169-180, 2011 (December)

Variations of Water Uptake, Lipid Consumption, and Dynamics during the Germination of Sesamum indicum Seed: A Nuclear Magnetic Resonance Spectroscopic Investigation

Germination in sesame seeds (Sesamum indicum L.) in water and in indole-3-acetic acid (IAA) solution is investigated with magic-angle-spinning (MAS) solid state nuclear magnetic resonance (NMR) spectroscopy, supplemented by liquid state NMR spectroscopy. The spectra show good resolution and can be assigned with sufficient confidence. The characteristic spectral peaks and relaxation rates were monitored during the entire course of germination for better understanding of the biophysical and biochemical mechanisms involved in the triphasic water uptake of the seed. A highly positive correlation is found between water uptake and lipid consumption during germination. No significant variation is observed in the relaxation times for the lipid protons during the first two stages of triphasic water uptake, while evident differences are observed for water proton relaxation rates in all stages. Although the total amount of water uptake is largely not changed as a result of IAA, the addition of IAA in seed-germination medium has shown some prominent effects on the germination process, e.g, it suppresses lipid consumption and water mobility, and it reduces the longitudinal and transverse relaxation times of lipid protons and causes a more scattered range for these parameters.

Studies on the isolation of normal and abnormal seedlings of Chrysophyllum albidum: A step towards sustainable management of the taxon in the 21st century

The authors’ field trip revealed that the local populace attempted to plantChrysophyllum albidum seeds but met with severe limitation. In the light of the above a study was designed to determine the optimum seed germination medium, normality and abnormality of seedlings. Of all the growth media used, 4 parts topsoil (4PTS) + 4 parts farm yard manure (4PFYM) had the best result. A mean seed germination value of 83% was obtained. Biomass accumulation was also highest in the medium of (4PTS + 4PFYM) from which mean fresh weight of 1.7 and 0.98 g dry weight were obtained respectively. Abnormality of seedlings was detected. It was such that the seed coat attached to the cotyledon and could not be removed without damage to the tender shoot. The study concluded that farmers generally sowed seeds directly, though the seeds may be viable and could germinate, most of the plantings failed due to seedling abnormality. Seedlings of C.albidum be raised in a tree nursery in a growth medium of 4PTS + 4PF YM, where the seedlings can easily be assessed. The abnormal seedlings should be identified, thinned our and well discarded. This will ensure successful forest plantation of C. albidum that can guarantee good returns on investment. Key words: Normal, abnormal, sustainable management, Chrysophyllum albidum.

The effect of in vivo and in vitro applications of ethrel and GA3 on sex expression in bitter melon (Momordica charantia L.)

Bitter melon (Momordica Charantia L.) is an important vegetable crop with nutritional and medicinal qualities. As a member of cucurbitaceae it is monoecious with varying proportions of staminate and pistillate flowers. This study was undertaken to determine the effects of various applications of ethrel and gibberellic acid (GA3) on sex modification in M. charantia. In the first set of experiments, various concentrations of hormones were added to the seed germination medium, in the second, adult plants growing in the field were sprayed with aqueous solutions of ethrel or GA3 three times at three-day intervals. The number and sex of open flowers was recorded daily for 60 days after the first flower opened and total number of staminate and pistillate flowers was calculated at the end of the experiment. The highest frequency (29.5%) of pistillate flowers was observed in plants treated with 500 ppm ethrel at germination. Similarly, spraying of adult plants with 100 ppm GA3 increased the proportion of pistillate flowers to 26% relative to 15% in untreated controls. Both ethrel and GA3 induced significantly higher number of pistillate flowers than control. In vitro hormone application during seed germination was much more successful than spraying of field grown plants.

(294) The Effect of Heavy Metal Cadmium on Transgenic and Nontransgenic Petunia Plants

Heavy metal contamination in the ground and its effects on human health has been a major concern. The objective of this experiment is to determine how cadmium affects transgenic and nontransgenic (control) petunia plants. Initially, the petunia seed germination medium (SGM) was prepared, and petunia seeds were sterilized and cultured on the SGM medium. During the actual experiment, using 8-day-old germinated petunia, the SGM-Cd media containing four different concentrations (0, 50, 100, and 200 μM) of CdCl2 were prepared. Plant growth and survival rates in four concentrations of SGM-Cd media were recorded. Over 20 days of observations, the plants showed two distinct differences: color and growth. For the first few days, all of the plants grew very slowly, but the plants showed marked differences in growth and color at later days. On the final day, 22 Jan., the control plants on 0 μM of CdCl2 grew 4.2 cm, while the transgenic plant grew 2.4 cm and showed a dark shade of green color. The control plants on 50 μM grew 1.38 cm, while the transgenic plants grew 2.2 cm. The control plants on 100 μM grew 1.14 cm, while the transgenic plants grew a total of 1.7 cm. Both control and transgenic plants on 200 μM had similar growth of 0.94 cm and showed very light shade of green color. The hypothesis in this experiment was confirmed because CdCl2 impacted the growth of the control and transgenic plants by stunting the growth of the plant and changing its color. It is also demonstrated here that transgenic plants containing the heavy metal transport (HMT) gene can grow better than control because of the specific HMT gene that allowed the plant to uptake more CdCl2 into the central vacuole.

Temperatura, nitrato de potássio e fotoperíodo na germinação de sementes de Hypericum perforatum L. e H. Brasiliense Choisy

Hypericum perforatum L. e H. brasiliense Choisy, da família Clusiaceae, são espécies de plantas de considerável valor medicinal. A primeira é comercialmente cultivada na Europa e largamente utilizada como fitoterápico para tratamento da depressão. A segunda é nativa do Brasil e, recentemente, vem sendo objeto de muitos estudos por possuir o mesmo potencial farmacológico. Neste trabalho, as sementes de ambas as espécies foram investigadas com relação à massa de mil sementes e a diversas condições de germinação, combinando-se quatro temperaturas, ou seja, 20, 25, 30 e 20-30 ºC, em presença ou ausência de luz e com ou sem umedecimento do substrato de germinação com solução aquosa de nitrato de potássio a 0,2%. O diminuto tamanho das sementes ficou bem revelado pelos valores da massa de mil sementes que foram de 0,13 g (7.692 sementes por grama) e 0,02 g (50.000 sementes por grama) para H. perforatum e H. brasiliense respectivamente. As temperaturas mais benéficas à germinação foram as alternadas de 20-30 ºC, para as duas espécies, ou as constantes de 20 ºC, para H. perforatum e de 30 ºC, para H. brasiliense. A luz foi necessária para a germinação das sementes das duas espécies, porém seu efeito foi mais pronunciado em H. brasiliense. Em H. perforatum o efeito da luz foi mais evidente a 20-30 ºC enquanto em H. brasiliense esse efeito acentuou-se em todas as temperaturas estudadas. A aplicação de nitrato de potássio a 0,2% foi eficaz para as sementes de H. brasiliense porém não afetou as de H. perforatum.

In vitro assay for 2,4-D resistance in transgenic cotton

2,4-Dichlorophenoxyacetic acid (2,4-D) resistant plants of transgenic cotton (Gossypium hirsutum L.) were produced using Agrobacterium tumefaciens containing a plasmid carrying the neomycin phosphotransferase II (npt II) and 2,4-D monooxygenase (tfd A) genes. An in vitro assay was performed to determine the sensitivity of seed germination, and the growth of seedlings of transgenic and non-transgenic cotton to various concentrations of kanamycin and 2,4-D. The results indicated that kanamycin caused the cotyledons of non-transgenic plants to turn white, but transgenic plants grew normally. Seed germination and seedling growth of non-transgenic plants were strongly inhibited by 2,4-D, but only slightly for transgenic plants. Transgenic plants and non-transgenic plants can be clearly distinguished by the use of 2 mg l−1 2,4-D in seed germination medium. There was a high correlation between the response of seed germination and the growth of seedlings to kanamycin or 2,4-D, based on the germination ration, albino ratio, dry weight or fresh weight. On this basis, we development a rapid method for identifying transgenic plants that has been verified in the field. These findings will allow identification of cotton transformants at an early stage of plant development, saving time and improving cultivars containing the 2,4-D resistance trait.

Apomictic embryo development and survival in Uapaca kirkiana under in vitro and in vivo seed germination

In vitro and in vivo studies on seed germination of Uapaca kirkiana were conducted at Bunda College of Agriculture. In vitro germination treatments included two fruit sources (market and direct from trees); seed coat (outer and inner layers) removal and two seed germination media (Murashige and Skoog (MS) and woody plant medium (WPM)). Incubation of in vitro cultures was under 16 h light at 45 μmol m −2 s −1 and they were maintained within the range 25–27°C. The in vivo seed germination experiment was set up in a green house with the two fruit sources as main factors and outer seed coat layer removal and non-removal as sub-factors. Data collection included number of germinating seeds, number of contaminated cultures and number of normal seedlings per seed. Removal of both outer and inner seed coat layers promoted the number of aseptic seedlings. Seed germinated on MS had a significantly higher frequency of normal seedlings (90%) and multiple seedlings/seed (90%) than WPM. Removal of the outer seed coat layer improved in vivo germination from 55% to 78% and from 35% to 95% for market fruits and direct from trees, respectively. The seeds exhibited apomixis with a maximum of nine seedlings/seed for in vitro, and two seedlings/seed for in vivo germination.

In vitro regeneration of Echinacea purpurea L.: Direct somatic embryogenesis and indirect shoot organogenesis in petiole culture

An in vitro propagation system was developed for Echinacea purpurea L. (purple coneflower), a medicinal plant commonly used in the treatment of colds, flu and related ailments. Echinacea seeds were found to be contaminated with systemic fungi and therefore an optimized minimal concentration of Plant Preservation Mixture (PPM) was incorporated in the seed germination medium to recover sterile seedlings. Regeneration was induced on petiole explants from 2-month-old sterile seedlings cultured on medium supplemented with benzylaminopurine (BAP) or thidiazuron (TDZ) in combination with indoleacetic acid (IAA). Two distinct forms of regeneration were identified in cultured petiole explants with histological and morphological observations, viz. the direct formation of somatic embryos on the epidermis and the de novo development of shoots from callus tissues formed in subepidermal cell layers. the results of this study have established a micropropagation system for E. purpurea that will provide sterile plant material for further investigations into medicinally active biochemicals and may facilitate mass production of high-quality E. purpurea plants for the commercial market.