Modified Woody Plant Medium Research Articles

Callus formation from root protoplasts of Quercus rubra L. (red oak)

Root protoplasts of Quercus rubra L. were isolated from 12 day old seedlings with an enzyme mixture containing Cellulase R1O + Rhozyme HP150 + Macerozyme R1O, supplemented with cysteine and bovine serum albumin.Protoplasts were purified by a Ficoll density gradient centrifugation and cultured at low density in a liquid medium. The modified woody plant medium, containing 2.2 μM benzyladenine + 1.8; μM zeatin + 5.3 μM α-naphthaleneacetic acid + 2.2 μM dichlorophenoxyacetic acid, allowed sustained divisions and formation of microcalluses.Protoplast - derived microcallus developed into green and compact callus when transferred to an agarose solidified medium, supplemented with casein hydrolysate and indole 3-acetic acid (devoid of 2,4 dichlorophenoxyacetic acid) and placed under low illumination.

Somatic Embryogenesis in Tissue Cultures of Pecan

Abstract Tissue cultures of pecan [Carya illinoensis (Wangenh.) C. Koch] were initiated from embryo explants collected weekly from 12 weeks post-pollination until fruit maturity. Three cultures derived from immature embryos collected 14 weeks postpollination produced primary somatic embryos within 1 month following transfer from modified woody plant medium (WPM) with 2.0 mgliter−1 2,4-D and 0.25 mg liter−1 BA in the light to hormone-free medium in the dark. Scanning electron microscopy documented the development of secondary embryos, which followed a globular, heartshaped, and torpedo-stage developmental sequence. Chemical names used: (2,4-di-chlorophenoxy) acetic acid (2,4-D), N-(phenylmethyl)-1H-purin-6-amine (BA), and 1H-indole-3-butanoic acid (IBA).

Rapid Multiplication of Heuchera sanguinea Engelm. ‘Rosamundi’ Propagated in Vitro

Abstract Shoots tips from in vitro cultures of Heuchera sanguinea Engelm. ‘Rosamundi’ were cultured on a modified woody plant medium containing one of 3 cytokinins (BA, 2iP, kinetin) or cytokinin plus NAA. BA and kinetin were the most effective stimulators of axillary shoot growth. Maximum shoot production (≥1 mm) occurred with 2, 4, 8, and 16 μm BA, or 16, 32, and 64 μm kinetin. The addition of NAA had no effect or reduced the number of shoots produced. Because of the rosette growth pattern, rooting of the resultant shoots was best accomplished by placing whole cultures in a soilless medium under high humidity and later dividing the rooted shoot masses. Chemical names used: N-(phenylmethyl)-1H-purin-6-amine (BA); N-(3-methyl-2-butenyl)-1H-purin-6-amine (2iP); N-(2-furanylmethyl)-1H-purin-6-amine (kinetin); and 1-naphthaleneacetic acid (NAA).

Rapid Multiplication of Veronica ‘Red Fox’ Propagated in Vitro

Abstract Shoot tips from in vitro cultures of Veronica spicata L. ‘Red Fox’ were grown on modified Woody Plant Medium containing one of 3 cytokinins or cytokinin plus NAA. Of the 3 cytokinins tested (BA, kinetin, and 2iP), BA was the most effective stimulator of axillary shoot growth. The greatest number of shoots greater than or equal to 5 mm in length was produced on medium containing 8 μM BA plus 0.01 μM NAA, whereas medium containing 2 μM BA plus 0.01 μM NAA produced the greatest number of shoots greater than or equal to 10 mm. Shoots were rooted and established at an 80% rate in a soilless medium under high humidity. Chemical names used: N-(phenylmethyl)-1H-purin-6-amine (BA); N-(3-methyl-2-butenyl)-1H-purin-6-amine (2iP); N-(2-furanylmethyl)-1H-purin-6-amine (kinetin); 1-naphthaleneacetic acid (NAA).

Survival and regeneration of American elm callus cultures after being frozen in liquid nitrogen

Ulmusamericana L. callus cultures were established from hypocotyls of aseptically germinated seeds and from three 18-month-old cell lines. Callus was treated with an aqueous cryoprotective mixture of polyethylene glycol, glucose, and dimethylsulfoxide (10, 8, and 10% w/v, respectively), frozen at 1 °C/min to −30 °C, and then immersed in liquid nitrogen. The callus was thawed rapidly, the cryoprotectant was washed out, and the callus was placed on Kao semisolid medium. Plantlets were regenerated from actively growing callus cultures by transfer to modified woody plant medium. Results suggest that preservation of germplasm for future tree improvement may be possible via liquid nitrogen storage of woody dicot callus.