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Michael W. Bairu, Manoj G. Kulkarni, Renée A. Street, Rofhiwa B. Mulaudzi, and Johannes Van Staden

other constant temperatures examined ( Table 1 ). Low (10, 15, and 20 °C) and high temperatures (35 °C) suppressed the growth of seedlings, indicating that these temperatures are not suitable for propagation of A. ferox . However, in the case of A

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Maria Papafotiou and Aekaterini N. Martini

), as well as of deforestation and habitat encroachment by urban and agricultural development. Thus, propagation protocols should be developed before expanding the species use. Seeds of T. capitatum have low (less than 40%) germination capacity ( Luna

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P. Prutpongse and P. Gavinlertvatana

Fifty-four out of 67 species of bamboo tested were successfully propagated in vitro. For nearly every species, multiple shoots were produced from axillary buds on stem node segments cultured on Murashige and Skoog medium containing BA. In a very few species plants could be regenerated adventitiously from callus. This method of propagation was not very efficient or reliable. Rooting occurred in media containing NAA at 2.7 to 5.4 μM. Several species could be stored in vitro on half-strength medium at room temperature > 15 months without transfer. Chemical names used: N6-benzylamino purine (BA); napthyleneacetic acid (NAA).

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Rolston St. Hilaire and Carlos A. Fierro Berwart

The effects of 1H-indole-3-butyric acid (IBA), cutting position on stock plants, the date of propagation, the type of rooting substrate and temperature on rooting of mussaenda (Mussaenda erythrophylla Schumach. & Thonn. `Ashanti Blood' and `Rosea', and Mussaenda philippica A. Rich `Aurorae') stem cuttings were determined. Cuttings of `Ashanti Blood' produced the largest number of roots when treated with 15 mmol (3000 ppm) IBA and rooted in perlite at 29 °C (84 °F). Cutting position on stock plants did not affect rooting in any of the three cultivars. Propagation date and temperature of the rooting medium affected root numbers in `Aurorae'. With `Rosea', only the type of rooting substrate affected root number. Rooting percentage was 22%, 48%, and 39% in `Ashanti Blood', `Aurorae', and `Rosea' respectively. After 30 days of propagation average root length was 4, 12, and 4 mm (0.2, 0.5, and 0.2 inch) in `Ashanti Blood', `Aurorae', and `Rosea' respectively. Growers must determine precise rooting conditions for each cultivar to obtain consistent rooting of cuttings. This process may not be economically feasible on a commercial basis because rooting percentages are relatively low. We conclude that other methods of clonal propagation need to be evaluated before uniform rooted stem cuttings of mussaenda can be produced economically.

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W.J. Carpenter and J.A. Cornell

The interactions among IBA concentrations and durations of treatment and propagation medium temperatures on the rooting of stem cuttings were compared for cultivars of Hibiscus rosa-sinensk L. Cultivar rooting was rapid with extensive root development for `Pink Versicolor', average for `Jim Hendry', and slow with few roots per cutting for `Silver Anniversary'. The IBA concentration and duration of treatment that cuttings required to reach maximum rooting declined with increase in medium temperature (from 18 to 34C). `Pink Versicolor' stem cuttings receiving 4- to 6-minute basal dips required 8000 ppm IBA with the medium at 18C, 6000 ppm at 26C, and 2500 ppm at 34C, to achieve 100% rooting of the cuttings. `Pink Versicolor' stem cuttings had the most roots at 10,000 ppm IBA, with 10-min stem dips best at 18C, 4 to 8 min at 26C, and 7 to 8 min at 34C. Maximum dry weights per root were achieved at 6000 ppm IBA, with longer basal stem dip durations needed at 18C than 26 or 34C. Lower IBA levels were required for 100% rooting of `Pink Versicolor' than for `Jim Hendry', with highest levels needed for `Silver Anniversary'. The results indicated that the benefits in rooting achieved from higher IBA levels greatly exceeded those that could be achieved by increased medium temperature. Chemical name used: indole-3-butyric acid (IBA).

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Sarah E. Bruce and D. Bradley Rowe

85 ORAL SESSION 17 (Abstr. 544–549) Woody Ornamentals/Landscape/Turf: Crop Production/Propagation Tuesday, 25 July, 10:00–11:15 a.m

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Puffy Soundy, Winnie Mpati, and Elsadu Toit

Fever tea (Lippiajavanica) is one of the important medicinal plants belonging to the Verbenaceae family. The first objective of this investigation was to study the propagation of fever tea using stem cuttings. The main variables studied were cutting position, rooting media and rooting hormone. The germination requirement of fever tea seed is also not known. Therefore, the second objective was to investigate the ideal seed germination temperature and light combinations. Germination was tested at constant temperature regimes (15, 20, 25 and 30 °C) with a continuous light or dark period and at alternate temperatures of 20/30 °C and 16/8 hour (light/dark) combinations, respectively. For the stem cutting investigation, sampling was done every 5, 10, 15, and 20 days from plant establishment. Apical cuttings took less time to root than basal cuttings regardless of growing medium. Response of cuttings to rooting hormone was growing medium-related. With rooting hormone, it took 10 days to root most of the apical cuttings, whereas basal cuttings showed more roots in 15 to 20 days after plant establishment. Cuttings in sand took 5 days longer to root than in pine bark, regardless of rooting hormone. Therefore, for quicker establishment of fever tea stem cuttings, rooting hormone and pine bark should be used for propagation of both apical and basal cuttings. In the germination investigation, it was found that fever tea seeds are positively photoblastic. Regardless of temperature, seeds failed to germinate in continuous darkness. The germination percentage was improved at continuous or alternating temperatures above 20 °C with continuous light. However, the germination percentage decreased with alternating light and dark treatments.

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Randall H. Hagen and David A. Palzkill

The `Desert Museum' hybrid between the Blue, Foothills, and Mexican palo verdes has been well received by the public. However, it has remained unavailable due to difficulties in asexual propagation. Studies were conducted on effects of IBA cone. (0 to 10,000 ppm), cutting position along the stem, size of cutting, season, and temperature of the medium.

For `Desert Museum', basal cuttings of slightly hardened new stem growth rooted much better than apical cuttings. Best rooting for apical cuttings was 79% using IBA from 2,500-5,000 ppm. Basal cuttings averaged 95% rooting and showed no response to IBA. Rooting of cuttings taken in September declined to 10% for apical and 2170 for basal cuttings averaged over all IBA levels. Six other species or hybrids of Cercidium and Parkinsonia and five of Prosopis were also rooted.

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Randall H. Hagen and David A. Palzkill

The `Desert Museum' hybrid between the Blue, Foothills, and Mexican palo verdes has been well received by the public. However, it has remained unavailable due to difficulties in asexual propagation. Studies were conducted on effects of IBA cone. (0 to 10,000 ppm), cutting position along the stem, size of cutting, season, and temperature of the medium.

For `Desert Museum', basal cuttings of slightly hardened new stem growth rooted much better than apical cuttings. Best rooting for apical cuttings was 79% using IBA from 2,500-5,000 ppm. Basal cuttings averaged 95% rooting and showed no response to IBA. Rooting of cuttings taken in September declined to 10% for apical and 2170 for basal cuttings averaged over all IBA levels. Six other species or hybrids of Cercidium and Parkinsonia and five of Prosopis were also rooted.

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Erika Szendrák and Paul E. Read

The temperate native terrestrial orchids are endangered species. Their propagation from seeds poses specific problems. It is well known that orchid seeds are devoid of endosperm and in nature they need microscopic fungi in a symbiotic relationship for germination. We developed a successful asymbiotic in vitro culture method for germinating seeds of several temperate orchid species and for maintaining the cultures of young plantlets. The medium used for both germination and seedling culture was a modified FAST medium. Seeds were surface-disinfested for 10 minutes in a 10% calcium hypochlorite solution. After sowing, the cultures were kept under dark condition at 10–12°C for 4 weeks. After that the cultures remained in the dark, but the temperature was raised to 25–26°C until germination occurred. Thereafter cultures required alternating seasonal temperatures: 25–26°C from the beginning of April to the end of September and 17–19°C from October to March. For the development of the young plantlets natural dispersed light and prevailing day-length was favorable. After 2 years of aseptic culture they were suitable for transfer ex vitro. Different stages of seed germination and plant development were observed using a scanning electron microscope and will be included in this presentation. Further observation of the effects of different environmental factors is currently under investigation.