You are looking at 1 - 10 of 23 items for
- Author or Editor: R. M. Skirvin x
Extensive root development was observed on Stage 2 `Red Emerald' philodendron shoots grown on standard multiplication medium consisting of Murashige and Skoog salts and vitamins with 6-benzylaminopurine (BA, 0.2 mg·liter-1. Root development was suppressed significantly when the level of NH4NO3 was doubled from standard levels (lx, 1650 mg·liter-1) to 3300 mg·liter-1 (2×). A higher level of NH4NO3 (3×, 4950 mg·liter-1) was detrimental to shoot growth and proliferation. This information may be useful for commercial propagators who wish to suppress root development at the shoot multiplication stage.
Acclimatization and growth of in vitro-derived apple shoots of two apple scion apple cultivars were compared under fogged conditions in a greenhouse and in a commercial growth cabinet (Phototron). Plant survival rates of microcuttings of `Royal Gala' and `Jonagold' were significantly better when maintained in the Phototron units than when grown in a greenhouse under fog. The number and length of roots on microcuttings was significantly higher in the Phototron than under fog. In the present study, we demonstrated that the Phototron environment was better than a fogged greenhouse for establishing apple shoots ex vitro. However, the Phototron units are so small that they hold no more than 100 to 120 plants at a time. Therefore, the units will be of most value to growers or individuals in laboratories who do not have a constant need for acclimatization facilities. Growers who acclimatize many plants should continue to use fogging or misting facilities.
In vitro techniques were developed to regenerate plantlets (calliclones) from callus of scented geraniums (Pelargonium spp.). Calliclones were compared to plants derived from stem, root, and petiole cuttings of 5 cultivars. Plants from stem cuttings of all cultivars were uniform and identical to the parental clone. Plants from root and petiole cuttings were more variable with the amount of variation dependent upon cultivar. High variability was associated with calliclones. Aberrant types included changes in plant and organ size, leaf and flower morphology, essential oil constituents, fasciation, pubesence, and anthocyanin pigmentation. Calliclone variation was dependent upon clone and age of callus. Variability in calliclones was due to segregation of chimeral tissue, euploid changes, and heritable changes which may involve individual chromosomal aberrations or simple gene mutations. Variability of calliclones might be exploited for improvement of vegetatively propagated crops especially highly polyploid, sterile lines.
Chimeral `Thornless Evergreen' (CTE), (Rubus laciniatus Willd.) somaclones selected in 1983 and field planted in 1985 were reexamined in 1992 for various vegetative and reproductive characteristics. Two major types of thornless (prickle-free) plants, intermediate-sized (`UI 6-6' = `Everthornless') and dwarf (`UI 6-4'), originally selected from a chimeral thornless parent plant, were compared with thorny plants. The intermediate and dwarf somaclones have maintained their distinctive habits over 7 years' growth in the field, indicating that their growth habits are stable and not a transient effect of tissue culture. Although the thornless somaclones remained thornless, the degree and type of prickle-like structures varies considerably, indicating that the thornless gene (S te) does not entirely suppress the production of prickles, but apparently alters their development. Increasing suppression was directly related to increasing dwarfism, suggesting a link between thornlessness and internode length.
Shoot proliferation of ‘Forever Yours’ greenhouse rose (Rosa hybrida L.) was a-chieved in vitro using a modified Murashige and Skoog (MS) high salt medium supplemented with 6-benzylamino purine (BA) at 2.0 mg/liter and naphthaleneacetic acid (NAA) at 0.1 mg/liter. Shoots were readily rooted on ¼ strength MS medium without hormones. Rooted shoots were successfully transferred to soil and grew well in the greenhouse.
A method has been developed for micropropagation of the difficult-to-root winegrape cultivar `Norton' (Vitis aestivalis). Plants were established in vitro from axillary bud cuttings of field-grown plants. Four levels of 6-benzylaminopurine (BA) and three levels of naphthaleneacetic acid (NAA) were tested in a factorial arrangement for their effectiveness in promoting multiplication of shoots from single-node explants. Three levels of NAA and two concentrations of Murashige and Skoog (MS) basal medium were tested for their effectiveness in promoting rooting of shoot tips. The greatest number of shoots per axillary bud in combination with the greatest shoot length were produced with 4 μmol·L-1 [0.90 mg·L-1 (ppm)] BA. NAA had no effect on shoot multiplication. NAA was not required for in vitro rooting. All rooted plants survived the transition to soil.
Although strawberry species have existed for an estimated 50 million years (17), and their use by man has been dated to the bronze age (19), only after the 14th century A.D. were strawberry plants gathered from the wild and grown in gardens. These first cultivated strawberry plants were grown for both ornamental and medicinal purposes (11). The strawberries of the past were different from those of today. The fruit was small, plants were not productive, and in many respects were far inferior to the large fruited cultivars that are now grown in many parts of the world.
Rapid proliferation of axillary buds of ‘Thornless Boysenberry’ and ‘Thornless Young-berry’ (Rubus sp.) in tissue culture has been achieved on a modified Murashige and Skoog (MS) medium containing 6-benzylamino purine (BA) and α-napthaleneacetic acid (NAA). Shoots were induced to root on medium consisting of MS high mineral salts, myo-inositol, and thia-mine·HCl diluted to 1/16 to 1/2 strength and supplemented with full strength sucrose and agar. Rooted plants have been successfully moved to soil and grown in the greenhouse.
Shoots of greenhouse-grown Algerian ivy (Hedera canariensis L.) were surface disinfected and explanted on modified Murashige and Skoog (MS) medium supplemented with BA (10 μm) and NAA (2.5 μm). One month later the shoots were transferred to MS proliferation medium supplemented with TDZ (0.1 or 0.5 μm) and NAA (40 μm). An average of three microshoots developed on each stem treated with TDZ. Pruned shoots grown on MS medium supplemented with GA3 (20 μm) and BA (20 μm) branched better than unpruned shoots (3.7 vs. 1 per explant, respectively). Rooted shoots grown ex vitro grew and developed a shape suitable for commercial sale in 3 months. Chemical names used: N -(phenyl-methyl)-l H -purine-6-amine (BA); gibberellic acid (GA3); 1-naphthaleneacetic acid (NM); N -phenyl-W-1,2,3-thiadiazo-5-yl urea (Thidiazuron, TDZ).
`Embryonic axes-derived `Burpless Hybrid' cucumber (Cucumis sativus L.) plantlets germinated on Murashige and Skoog (MS) medium supplemented with 16 combinations of BAP and NAA and seedlings derived from whole seeds cultured on semi-solid agar were inoculated in vitro with two isolates (WFU3 and WFM13) of Pythium aphanidermatum. All axes-derived plantlets and whole seedlings inoculated with WFM13 isolates were susceptible to blight and died 2 days after inoculation. Similarly, all seedlings inoculated with WFU3 isolates were killed within 2 days after inoculation; however, the rate of development and severity of blight varied among the axes-derived plantlets. Blight on axes-derived plantlets, regenerated on MS medium supplemented with 2 mg BAP/liter and 0.2 mg NAA/liter, was significantly less than on regenerants cultured on all other amended MS media. On some media, callus developed on crowns and/or primary roots. The presence of callus influenced resistance to Pythium. In a second experiment, axes-derived cucumber regenerants from five genotypes, cultured on MS medium supplemented with 2 mg BAP/liter and 0.2 mg N&A/liter, were compared for their resistance to P. aphanidermatum isolate WFU3. Resistance was significantly greater for `Burpless Hybrid' and `Sweetslice' than for three other genotypes. Chemical names used: 6-benzylaminopurine (BAP); α -naphthaleneacetic acid (NAA).