In vitro propagation of Vitis vinifera L. cv. 'Monastrell'

Background: A protocol for the micropropagation of the grape (Vitis vinifera L.) cultivar 'Monastrell' was developed. Initial plant material was obtained from the sanitary selection of grapevine plants performed by real-time RT-PCR to confirm the absence of Grapevine fanleaf virus, Arabis mosaic virus, Grapevine leafroll-associated virus 1, Grapevine leafroll-associated virus 3, and Grapevine fleck virus. Results: The effects of the salt composition (comparing Lloyd and McCown woody plant medium and Murashige and Skoog medium 1/2 macronutrients) and the growth regulator benzylaminopurine (BAP), at 0 and 8.9 µM, on plant propagation were evaluated using nodes as explants. The most efficient procedure consisted of bud induction in the medium with Lloyd and McCown woody plant salts and 8.9 µM BAP for 30 d along with elongation in cytokinin-free medium for 60 d, which gave 22 nodes/explant (174 plants/initial plant). A second cycle of propagation in a medium without BAP for another 60 d could give approximately 10,000 nodes, which can be obtained after an additional 2 months of culture. All plants acclimatized after the second cycle of multiplication were successfully transferred to soil. Conclusion: We developed an optimal protocol for V. vinifera cv. 'Monastrell' micropropagation, the first described for this cultivar.

Histology of the regeneration of Paulownia tomentosa (Paulowniaceae) by organogenesis / Histología de la regeneración por organogénesis en Paulownia tomentosa (Paulowniaceae)

Paulownia tomentosa is a fast-growing tree species with a considerable economic potential because of its value for wood as well as its high biomass production, and elevated stress tolerance. The objective of the present study was to evaluate the development of adventitious buds in leaves obtained from four-week-old shoots of P. tomentosa, in order to identify the cells involved in in vitro adventitious bud development. Leaves (proximal halves with the petiole) from the first node were excised from four-week-old micropropagated shoots, and cultured on Murashige and Skoog medium, supplemented with 3% (w/v) sucrose, 0.6% (w/v) Sigma agar, 22.7µM thidiazuron (TDZ) and 2.9µM indole-3-acetic acid for two weeks, explants were then transferred to the same medium with 0.44µM N6-benzyladenine for another four weeks. Five explants were collected daily during the two first weeks in TDZ treatment. A total of 140 samples were processed. Most of the buds developed indirectly from the callus formed in the petiole stub, and they became visible after eight-ten days of culture, although some buds were also observed in the area of the laminar cut at the level of the veins. The first histological changes could be observed after two-three days of culture, with the dedifferentiation of some subepidermal and inner parenchyma cells, which exhibited a large, prominent nucleus, densely-stained cytoplasm and a high nucleusto-cell area ratio. Proliferation of these cells gives rise to meristemoid formation after seven-ten days of culture. Organized cell division in meristemoids allows the formation of bud primordia that emerged from the explants surface. The progressive structural differentiation of the apical meristem, leaf primordia, and procambium strands, led to formation of complete buds that were observed in the exterior of the explants after 10-15 days of culture. Direct development of buds from cells in the subepidermic and/or epidermic layers were observed ...

Paulownia tomentosa es un árbol de rápido crecimiento y con un gran potencial económico por su madera, su utilización para la producción de biocombustible, así como su alto rendimiento en la producción de biomasa y su elevada tolerancia al estrés. El objetivo del presente trabajo ha sido evaluar el desarrollo a nivel histológico de yemas adventicias en hojas de Paulownia tomentosa. Hojas del primer entrenudo de brotes de cuatro semanas cultivados in vitro, fueron cultivadas en medio de Murashige y Skoog complementado con 22.7µM tidiazuron y 2.9µM ácido indol acético durante dos semanas. Los explantos fueron posteriormente transferidos a igual medio con 0.44µM N6 -benciladenina durante otras cuatro semanas. Se recogieron cinco muestras diarias durante las dos primeras semanas de tratamiento en medio con TDZ, procesando un total de 140 muestras. La mayoría de las yemas se desarrollan indirectamente a partir del callo formado en la superficie de corte del pecíolo. Después de dos-tres días de cultivo se observan los primeros cambios histológicos, con la desdiferenciación de algunas células de las capas subepidérmicas y del parénquima interno. La posterior proliferación de estas células da lugar a la formación de los meristemoides después de siete-diez días de cultivo. La progresiva diferenciación de estos meristemoides da lugar a la formación de las yemas que son visibles al exterior a partir de los 10-15 días. En la superficie adaxial del pecíolo se observó la formación de yemas adventicias de forma directa. Este protocolo puede ser de gran utilidad para la determinación de las células más adecuadas para los procesos de transformación genética.

In Vitro Propagation of Alternanthera sessilis L. from Internode Explant.

An efficient protocol was developed for micropropagation of Alternanthera sessilis L. from internode explant. Callus was developed from the cut ends and surface of the internode explants when the Murashige and Skoog (MS) medium was supplemented with 0.5mg/L or 1.0mg/L 2,4-D. The greatest mean number of shoots (124) with the highest mean shoot length (9.3cm) was obtained when calli were cultured on the MS medium with 1.0mg/L each of 6-Benzylaminopurine and adenine sulfate. Early and maximum root induction was noted when shoots were cultured in half strength MS basal medium. In vitro regenerated plants were successfully hardened in a mixture of soil and cow dung in ratio of 3:1 and transferred to field. Cent percent plants survived in field condition, morphologically identical to parent plant and showed normal flowering.

Efficient Regeneration of Eucalyptus urophylla x Eucalyptus grandis from Stem Segment

The aim of the present study was to establish an efficient regeneration system for the hybrid E. urophylla x E. grandis by means of organogenesis. Stem segments from seedlings were used as explants and cultured in a modified Murashige and Skoog medium (MS), supplemented with 13.2 µM N-phenyl-N'-[6-(2-chlorobenzothiazol)-yl] urea (PBU) and 0.285 µM indole-3-acetic acid (IAA). PBU was a useful growth regulator. After cultivating for 5 d, 96% explants formed callus. After 30 d, the calli obtained were transferred to MS medium containing different combinations of 6-benzyladenine (BA) and naphthalene acetic acid (NAA). Compared with other growth regulator combinations, PBU stimulated more vigorous calli and restrained browning. In addition, a large percentage (91.3%) of the calli induced by PBU showed adventitious buds formation. Shoot elongation was then stimulated on half-strength MS mineral salts medium supplemented with 6.6 µM PBU and 0.285 µM IAA for 20 d. For rooting, the elongated shoots were cultivated on root induction medium containing 2.46 µM indole-3-butyric acid (IBA). Plantlets were then successfully transplanted to a greenhouse. This procedure represented an efficient way of E. urophylla x E. grandis plant regeneration.