Increased ethylene and decreased phenolic compounds stimulate somatic embryo regeneration in leaf thin section cultures ofDoritaenopsis hybrid

2006 ◽  
Vol 49 (5) ◽  
pp. 358-363 ◽  
Author(s):  
So-Young Park ◽  
Kong Sik Shin ◽  
Kee Yoeup Paek
Author(s):  
Sulistyani Pancaningtyas

Cocoa (Theobroma cacao L.) like most tropical trees is recalcitrant in tissue culture. Somatic embryogenesis is generally efficient micropropagation technique to multiply elite material. However, Somatic embryogenesis in cocoa is difficult and this species is considered as recalcitrant. One of the factors often considered as a component of in vitro recalsitrance is a high phenolic content and oxidation of these compounds. In cocoa tissue culture accumulate large amounts of poliphenolics compounds which probably impair further development. This study was conducted to investigate the composition of phenolic compounds in cocoa flower and leaves, and their changes troughout the somatic embryogenesis process. Calli were induced in cacao floral and leaves explants on a half-strenght Murashige and Skoog medium containing 30 g/L Glucose and combination of 2,4 dichlorophenoxyacetic acid (2,4 D) with kinetin (kin). Total polyphenol content was observed on Sulawesi 1 cocoa clone. Embryogenic and non-embryogenic callus were also compared. The percentage of callus production from flower tissue is 85%, percentage of embryogenic callus 40 %, although  the percentage of somatic embryo production from embryogenic callus callus is 70%. The conservation of callus into somatic embryos followed by decline in phenol content and an increase in peroxidase. The synthesis kinetics for these compounds in calli, under different somatic embryogenesis conditions, revealed a higher concentration under non-embryogenic conditions. So that, phenolic compound can influence the production of calli and an absence the phenolic compound can enhance production of somatic embryo.Kata kunci: Theobroma cacao L., polifenol, embrio somatik, kalus, flavonoid, katekin, in vitro recalcitance


HortScience ◽  
2006 ◽  
Vol 41 (4) ◽  
pp. 1066D-1067
Author(s):  
Jae-Dong Chung ◽  
Hong-Yul Kim ◽  
Jung-Hae Suh ◽  
Oh-Chang Kwon ◽  
Chang-kil Kim

Somatic embryo formation was observed on thin-sectioned leaf explants within 3 weeks of culture from two Phalaenopsis hybrids—Phalaenopsis Hwafeng Redjewell `Ching Ruey' Phalaenopsis Chingruey's Giant Ching Ruey' (R×R), and Phalaenopsis Formosa Best Girl Ching Ruey' Depts. Lih Jiang Beauty `S 566' (WR×WR). Frequency of somatic embryo formation was higher in hybrid WRxWR than R×R and optimal concentration of TDZ for the induction of somatic embryos was 9.08 μM. In (WR×WR) embryo proliferation was simultaneously observed after transferring the explants with somatic embryo clumps onto PGR-free half-strength MS medium. Six months after initiation, the culture plantlets were produced. This is the first report on somatic embryogenesis induced directly from the leaf explants using TDZ in Phalaenopsis.


Author(s):  
Frederick A. Murphy ◽  
Alyne K. Harrison ◽  
Sylvia G. Whitfield

The bullet-shaped viruses are currently classified together on the basis of similarities in virion morphology and physical properties. Biologically and ecologically the member viruses are extremely diverse. In searching for further bases for making comparisons of these agents, the nature of host cell infection, both in vivo and in cultured cells, has been explored by thin-section electron microscopy.


Author(s):  
E. Keyhani

The mutagenic effect of ethidium bromide on the mitochondrial DNA is well established. Using thin section electron microscopy, it was shown that when yeast cells were grown in the presence of ethidium bromide, besides alterations in the mitochondria, the plasma membrane also showed alterations consisting of 75 to 110 nm-deep pits. Furthermore, ethidium bromide induced an increase in the length and number of endoplasmic reticulum and in the number of intracytoplasmic vesicles.Freeze-fracture, by splitting the hydrophobic region of the membrane, allows the visualization of the surface view of the membrane, and consequently, any alteration induced by ethidium bromide on the membrane can be better examined by this method than by the thin section method.Yeast cells, Candida utilis. were grown in the presence of 35 μM ethidium bromide. Cells were harvested and freeze-fractured according to the procedure previously described.


Author(s):  
P. Satir ◽  
J. Wais-Steder ◽  
J. Avolio
Keyword(s):  

In 1977, Sale and Satir showed that active microtubule sliding in trypsin-treated Tetrahymena axonemes is always of a single polarity. If the doublet bearing active arms is labelled N, by convention, the doublet that is pushed by those arms is N+l. In active sliding in trypsin-treated axonemes doublet N+l is always displaced tipwards with respect to N. Several different configurations of the dynein arms have been described. These include: (1) an extended configuration, where the dynein arms are tilted about 40° towards the base of the axoneme and are long enough to span the space between doublets N and Ntl completely (2) a standard, unattached image, such as is usually seen in thin section. In this configuration, the arms do not span the interdoublet gap. (3) the rigor image, where the arms always bridge the gap. This differs from the extended configuration because tilt is often absent, so that the arms often lie normal to doublets N and N+l.


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