Micropropagation of Citrus halimii – an endangered species of South-east Asia

A successful system of direct organogenesis is described for the wild citrus tree, Citrus halimii Stone which used in vitro seedling explants cultured on Murashige and Skoog medium supplemented with 0.4–11.1 μM 6-benzyladenine. Hypocotyl was the best explant for multiple shoots regeneration. Maximum number of shoots was obtained on medium with 2.2–11.1 μM 6-benzyladenine. Rooting of regenerated shoots was best on Murashige and Skoog medium supplemented with 2.7 μM α-naphthalenacetic acid. In vitro and ex vitro rooted plantlets survived (on average 83.3%) after being transferred to the soil mixture consisting of soil, sand and organic material (1: 1: 1) and kept in the glasshouse. This revised version was published online in June 2006 with corrections to the Cover Date.     

甘蓝型油菜叶柄原生质体培养再生植株

Two cultivars of Brassica napus,Altex and Canadian twins,were used as materials.Protoplasts isolated from petioles of plants grown in vitro were cultured in Nitsch mediumsupplemented with 0.5mg/L BA,0.5mg/L NAA,1mg/L 2,4-D,100mg/L serine,800mg/Lglutamine,4% sucrose and 0.4mol/L mannitol.After 2 days of culture,the first division wasobserved.The division frequency estimated after 10 days of culture was 30—60%.One weekafter transferring onto MS medium containing 6mg/L GA_3 and 3mg/L BA,protoplast-derivedcalli regenerated into shoots.The regeneration frequency of the two cultivars was 24% and31% respectively.It was found that the protoplasts isolated from petioles could float on thesurface of the 3% sucrose contained solution which was very favourable both to purificationand culture of the protoplasts.     

‘章姬'草莓茎段愈伤组织诱导及高频植株再生体系的建立北大核心CSCD

In order to cultivate an improved variety with higher potential yield and establish an efficient in vitro regeneration system of strawberry ‘Akihim'(Fragaria × ananassa), callus induction and plant regeneration protocol was designed for solve browning problem. A formal L9(34)orthogonal experiment was designed to investigate the browning research in primary culture using explants of creeping stems excised from aseptic seedlings. Based on the improved medium above, single-factor experiments were conducted to select effective plant growth regulators and appropriate concentrations on blank MS medium. A L9(34)orthogonal experiment was designed to study effects of types and concentrations of plant growth regulators on callus induction, adventitious shoot formation, and plant regeneration. The results indicated that MS medium was inferior to B5 and 1/2MS in inhibiting browning condition. The browning rate was dramatically reduced while the callus still survived on the medium with the addition of 20 g·L-1 Na2S2O3. The callus induction and shoot formation of the explants were observed on MS + 0.1 mg· L-1 6-BA + 0.05 mg·L-1 2, 4-D + 0.1 mg·L-1 NAA with effective inhibiting browning. The optimal medium protocol for multiple shoots proliferation was MS + 0.1 mg·L-1 6-BA + 0.1 mg·L-1 NAA where the proliferation coefficient was 12.86 after 30 d. Healthily regenerated plants were yielded on culture medium 1/2MS + 1.0 g·L-1 AC after 35 d, with a rooting rate of 92.50%. More than 95% of plantlets survived after transplanting into field. The rapid propagation system is helpful to provide homogeneous progeny and high quality seedlings for cultivation of strawberry ‘Akihime' as well as a technical reference for other strawberry species in vitro regeneration. [ABSTRACT FROM AUTHOR]     

Effect of phytohormones on plant regeneration from callus ofGladiolus cultivar “Jenny Lee”

Summary Callus capable of plant regeneration was initiated at a higher frequency from the basal leaves of in vitro plants (70% explants) as compared to cormel slices (30% explants) when cultured on medium containing various concentrations of auxin. The greatest number of plants were regenerated from 4-mo.-old callus (112 plants/g fresh weight callus) cultured on medium containing 10 mg/liter (53.8μM) 1-napthaleneacetic acid. The addition of 2 mg/liter (9.3μM) kinetin to a Murashige and Skoog’s basal salts regeneration medium resulted in an average two- to three-fold increase in the number of plants regenerated compared to regeneration on medium without hormones. Ten months after callus initiation, all callus maintained on auxin-supplemented media showed a drastic reduction in its capacity to regenerate plants. Ten-month-old callus maintained on dicamba regenerated the greatest number of plants (14 to 23 plants regenerated per gram fresh weight callus) as compared to callus maintained 10 mo. on medium containing 1-napthaleneacetic acid or 2,4-dichlorophenoxyacetic acid. Cormel slices cultured on cytokinin-supplemented media formed small amounts of callus which regenerated up to 19 plants per cormel slice within 1 to 2 mo. after the cormel slice had been placed on either 10 mg/liter (49.2μM) N⁶-2-isopentenyladenosine or 1 mg/liter (4.4μM) 6-benzylaminopurine.     

Direct shoot formation and plant regeneration from cotyledon explants of rapid-cycling Brassica rapa

Summary An in vitro culture system for direct shoot regeneration from cotyledon explants of rapid-cycling Brassica rapa was developed. Cotyledons from 3-d-old seedlings, when cultured on Murashige and Skoog (MS) medium supplemented with 20 μM N⁶-benzyladenine (BA) and 2 μM α-naphthaleneacetic acid (NAA), regenerated shoots directly at a frequency of 20%. The addition of 2 μM aminoethoxyvinylglycine (AVG) to this medium increased shoot regeneration to 33%, but silver nitrate drastically inhibited shoot regeneration. Shoot regeneration occurred directly, at the petiolar cut ends of cotyledonary explants, between 10 to 17 d in culture. The highest percentage of regeneration (33%) was obtained from 3-d-old seedlings. NAA was the most effective auxin for root induction and development, with 49% of shoots producing roots after 2 wk on medium containing 1.0 μM NAA. Regenerated plantlets were grown to maturity in pots containing peat moss and vermiculite (1:1). These plants were morphologically normal and fertile. With this protocol, over 100 independently derived, flowering R₀ plants were obtained from 40 regenerating cotyledonary explants within 40 d after culture initiation.     

从小麦雄性不育系的未授粉子房诱导单倍体植株

采用N₆培养基为基本培养基,附加不同水平的生长素,培养普通小麦、小麦雄性不育系及其保持系共10个材料的未授粉子房,所用的材料都能诱导出愈伤组织,出愈率在4.2-38.1%。经分化培养分别从T型不育系和太谷核不育材料获得了单倍体植株。供试材料的基因型、培养基中的生长素的种类及用量,对诱导愈伤组织及分化绿苗有重要的作用。 The unpollinated ovaries of male sterile lines and its manitainers of wheat, as well as common wheat, were cultured on N6 medium in vitro,when the pollen of the same panicle were at uninucleate stage. Callus were obtained from all of the materials, haploid plantlets were regenerated from the unpollinated ovaries of timopheevi cytoplasm male sterile line (T75-3369A) and Taigu nucleus male sterile line (Tal x C⁶⁸⁴₁).     

Micropropagation of Spathoglottis plicata

A rapid and reliable micropropagation method was established for Spathoglottis plicata. Nodal and leaf explants dissected from 8-month-old pot-grown seedlings were cultured on charcoal-amended Murashige and Skoog medium supplemented with 16 combinations of α-naphthaleneacetic acid (NAA) and 6-benzylaminopurine (BA) at concentrations of 0.54–10.74 μm. Regeneration of protocorm-like bodies (PLBs) and subsequent plantlet development were observed from 98.5% of the nodal explants. Only 6.5% of leaf explants and occasionally some root segments (dissected from regenerated plantlets) were able to produce PLBs and then plantlets. The optimum plant growth regulator (PGR) combination for maximal PLB regeneration was 5.37 μm NAA and 0.44 μm BA. The best combination of PGR for plantlet development was 2.69–10.74 μm NAA and 8.88 μm BA. The NAA to BA ratios for maximal PLB induction and plantlet development were 12.2 and 0.3–1.2, respectively. Regenerated PLBs and plantlets, when cut into pieces of less than 1 mm and subcultured onto the above media, regenerated new PLBs and plantlets in another 3 months. Received: 20 February 1997 / Revision received: 27 May 1997 / Accepted: 16 June 1997     

NaCl and TDZ are Two Key Factors for the Improvement of In Vitro Regeneration Rate of Salicornia europaea L.

The present study aimed to find out suitable conditions for the In vitro culture of Sallcornla europaea L. and to develop an efficient regeneration system. S. europaea plants were regenerated successfully In vitro from callus derived from mature embryos. Via the method of 2,4-dlchlorophenoxyacetlc acid （2,4-D）-short-treatment on mature seeds, callus was Induced from hypocotyls on the MS medium with 4.55 μmol/L N-phenyl-N＇-1, 2, 3-thladlazol-5-yl urea （TDZ） 3-4 weeks after the seeds germinated. The callus differentiated Into shoots at a rate of 27.6% after subculture for one time on the same medium. When NaCl was Included In the medium, shoots were formed In cluster and the shoot differentiation frequency was Increased to 55.2%. The shoots were rooted when cultured on 1/2 MS medium supplemented with Indole-3-butyric acid （IBA）, kinetin （KN） end activated charcoal （AC）. The results Indicated that NeCl and TDZ played an Important role In the Improvement of the regeneration rate of the halophyte, S. europaea.     

Genetic transformation of gentian using wild-type Agrobacterium rhizogenes

Leaf sections of greenhouse-grown Miscanthus x ogiformis Honda 'Giganteus' plants and leaf sections or shoot apices of in vitro shoot cultures were grown on Murashige and Skoog medium containing various concentrations of benzyladenine (BA) and 2,4-dichlorophenoxyacetic acid. On leaf sections, the callus induction decreased with increasing BA concentration. The percentage of embryogenic callus was increased, the percentage of root-forming callus decreased, and a new shoot-forming callus type was formed by inclusion of BA during callus induction. A higher percentage of shoot-forming callus was formed on shoot apices compared with leaf sections of in vitro-grown shoots when cultured on 0.4 μM BA. The largest number of plants per callus piece was regenerated from shoot-forming callus, but maintenance of the high regeneration capacity proved difficult. This revised version was published online in June 2006 with corrections to the Cover Date.     

In vitro regeneration of Minthostachys andina (brett) Epling - a Bolivian native species with aromatic and medicinal properties

Various explants of Minthostachys andina (Brett.) were evaluated for their morphogenic potential under in vitro culture conditions. Axillary buds derived from 2 year-old plants grown in MS-medium supplemented with 4.4 or 8.8 μM BA and 0.054 μM NAA, initiated shoot growth and new shoot formation. Under subculture in NN medium, shoots were rooted in the presence of NAA (1.6, 2.7 or 5.3 μM) alone or in combination with IBA (9.8 μM), and the regenerated plantlets were later acclimatised in the greenhouse. Also, polynodal segments from seedlings initiated multiple shoots and plantlets when initially cultured in presence of NN-liquid salt medium supplemented with 2.2-17.7 μM BA or 4.5-13.6 M TDZ in combination with different auxin-like growth regulators and after a final transfer for root initiation. The same types of responses were found in hypocotyl and leaf explants, which produced adventitious shoots in the presence of TDZ. The use of antioxidants helped to prevent browning and favoured organogenesis. This revised version was published online in June 2006 with corrections to the Cover Date.     

Investigation of the mechanism of temperature sensitivity of the electroreceptors of ampullae of lorenzini

In experiments on Black Sea skates (Raja clavata), the potential of the receptor epithelium of the ampullae of Lorenzini and spike activity of single nerve fibers connected to them were investigated during electrical and temperature stimulation. Usually the potential within the canal was between 0 and –2 mV, and the input resistance of the ampulla 250–400 k. Heating of the region of the receptor epithelium was accompanied by a negative wave of potential, an increase in input resistance, and inhibition of spike activity. With worsening of the animal's condition the transepithelial potential became positive (up to +10 mV) but the input resistance of the ampulla during stimulation with a positive current was nonlinear in some cases: a regenerative spike of positive polarity appeared in the channel. During heating, the spike response was sometimes reversed in sign. It is suggested that fluctuations of the transepithelial potential and spike responses to temperature stimulation reflect changes in the potential difference on the basal membrane of the receptor cells, which is described by a relationship of the Nernst's or Goldman's equation type.I. P. Pavlov Institute of Physiology, Academy of Sciences of the USSR, Leningrad. I. M. Sechenov, Institute of Evolutionary Physiology and Biochemistry, Academy of Sciences of the USSR, Leningrad. Pacific Institute of Oceanology, Far Eastern Scientific Center, Academy of Sciences of the USSR, Vladivostok. Translated from Neirofiziologiya, Vol. 12, No. 1, pp. 67–74, January–February, 1980.     

Principles of organization and evolution of systems of regulation of functions

Evolution of living organisms is closely connected with evolution of structure of the system of regulations and its mechanisms. The functional ground of regulations is chemical signalization. As early as in unicellular organisms there is a set of signal mechanisms providing their life activity and orientation in space and time. Subsequent evolution of ways of chemical signalization followed the way of development of delivery pathways of chemical signal and development of mechanisms of its regulation. The mechanism of chemical regulation of the signal interaction is discussed by the example of the specialized system of transduction of signal from neuron to neuron, of effect of hormone on the epithelial cell and modulation of this effect. These mechanisms are considered as the most important ways of the fine and precise adaptation of chemical signalization underlying functioning of physiological systems and organs of the living organism