Articles
CLONAL PROPAGATION OF ONCIDIUM THROUGH THE CULTURE OF FLORAL BUDS
Article number
482_46
Pages
315 – 320
Language
Abstract
Oncidium is a tropical orchid propagated by simple division of pseudobulbs or by tissue culture methods.
The latter has increased for clonal propagation of attractive Oncidium hybrids, as cut flowers.
The aim of this research is to development a clonal propagation methodology of Oncidium Gower ramcey hybrid through floral bud.
The plant material was floral buds from immature inflorescence, which were washed in tap water, then surface-sterilized for ten minutes in 2% sodium hypochlorite solution.
After washing 3 times in sterile distilled water, the floral buds were excised to a length of 1 mm under a stereomicroscope.
The explants were planted on Knudson C culture medium to induce protocorm-like body (PLB) formation.
This culture medium was supplemented with 1 mg · L-1 NAA, 120 ml · L-1 pineapple juice, 100 g · L-1 green banana fruit pulp or ripe ones, 20 g · L-1 sucrose and 8 g L-1 agar.
The pH prior to autoclaving was adjusted to 4.8. After two months, single PLBs were subcultured on Murashige & Skoog (MS) liquid medium to induce PLBs multiplication and plantlets formation.
Liquid medium was supplemented with auxin (0.0; 0.5 and 1.0 mg · L-1 NAA), cytokinin (0.0; 5.0 and 10.0 mg · L-1 BAP) and 20 g · L-1 sucrose. 10 ml solid medium was poured into 12 x 120 mm test tubes and 13 ml liquid medium into 250 ml flasks, which were placed on a circular shaker at 100 rpm.
Both liquid and solid cultures were maintained at 23±1° C under 16 h photoperiods.
Two months after culture, 75% of floral bud explants were better differentiated into PLB in the presence of green banana fruit pulp and pineapple juice in the medium, than with ripe ones.
The effects of the green banana are not clear yet.
The best treatment to induce PLBs multiplication and plantlets formation was 0.5 mg 1-1 NAA and 5.0 mg · L-1 BAP. The rate growth of PLBs was 1: 8 each 4 weeks.
The 100% of the plantlets were formed after 4 months.
The culture medium without hormones did not induce new PLBs.
Abnormal PLBs were formed with 1 mg · L-1 NAA and 10 mg · L-1 BAP. These results suggested that applications of exogenous hormones in low concentration, were indispensable for PLBs multiplication, but not for plantlets formation. Oncidium clonal propagation through floral bud can be used to obtain thousands of plantlets in short time with the same characteristics.
The latter has increased for clonal propagation of attractive Oncidium hybrids, as cut flowers.
The aim of this research is to development a clonal propagation methodology of Oncidium Gower ramcey hybrid through floral bud.
The plant material was floral buds from immature inflorescence, which were washed in tap water, then surface-sterilized for ten minutes in 2% sodium hypochlorite solution.
After washing 3 times in sterile distilled water, the floral buds were excised to a length of 1 mm under a stereomicroscope.
The explants were planted on Knudson C culture medium to induce protocorm-like body (PLB) formation.
This culture medium was supplemented with 1 mg · L-1 NAA, 120 ml · L-1 pineapple juice, 100 g · L-1 green banana fruit pulp or ripe ones, 20 g · L-1 sucrose and 8 g L-1 agar.
The pH prior to autoclaving was adjusted to 4.8. After two months, single PLBs were subcultured on Murashige & Skoog (MS) liquid medium to induce PLBs multiplication and plantlets formation.
Liquid medium was supplemented with auxin (0.0; 0.5 and 1.0 mg · L-1 NAA), cytokinin (0.0; 5.0 and 10.0 mg · L-1 BAP) and 20 g · L-1 sucrose. 10 ml solid medium was poured into 12 x 120 mm test tubes and 13 ml liquid medium into 250 ml flasks, which were placed on a circular shaker at 100 rpm.
Both liquid and solid cultures were maintained at 23±1° C under 16 h photoperiods.
Two months after culture, 75% of floral bud explants were better differentiated into PLB in the presence of green banana fruit pulp and pineapple juice in the medium, than with ripe ones.
The effects of the green banana are not clear yet.
The best treatment to induce PLBs multiplication and plantlets formation was 0.5 mg 1-1 NAA and 5.0 mg · L-1 BAP. The rate growth of PLBs was 1: 8 each 4 weeks.
The 100% of the plantlets were formed after 4 months.
The culture medium without hormones did not induce new PLBs.
Abnormal PLBs were formed with 1 mg · L-1 NAA and 10 mg · L-1 BAP. These results suggested that applications of exogenous hormones in low concentration, were indispensable for PLBs multiplication, but not for plantlets formation. Oncidium clonal propagation through floral bud can be used to obtain thousands of plantlets in short time with the same characteristics.
Authors
G.E. Santana, K. Chaparro
Keywords
Tropical orchid, micropropagation, hybrid, Gower ramcey, simpodial orchid
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