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Callus were induced from leaves or receptacles of
Dendranthema grandiflora (Ramat.)Kitamura cultivars, such
as ''Shiu Fang Chih Li'', ''Costume'', ''Monami'' and ''Red Small
Mum''. The factors affected callus proliferation and shoots
regeneration were studies. In addition, shoots regeneration from
leaf callus which radiated by gamma ray were compared with
unradiated plants. Callus formation from leaves explants
were cultured on the medium containing basal MS medium,30 g/l
of sugar. 5 mg/l of IAA, 10 mg/l BA, 1 mg/l of 2,4-D, and
solified by 8 g/l of Difco Bacto agar. Callus proliferation and
shoot regeneration of ''Shiu Fang Chih Li'' and ''Red Small Mum''
were profited when medium containing basal MS medium, 30 g/l of
sugar, 10 mg/l of IAA, and 10 mg/l of BA. ''Costume'' callus
cultured on basal MS medium, 0.5 or 1 mg/l of IAA,1 mg/l of
IAA, 1 mg/l of BA developed more fibrous callus, and had more
shoots. Callus growth of ''Monami'' were limited and browning by
increasing IAA concen- tration. Medium containing 0.05 or 0.1
mg/l of NAA and 0.5 mg/l of BA was suitaable for ''Monami''callus
proliferation and shoots formation. 6 or 8 g/l agar promoted
callus growth, medium without plant growth regulators
accelerated shoots elonglation and root initated. 30 or 20 g/l
sucrose was favorable for plantlets growth in vitro and
survival ex vitro. The plant characteristics was different
among 4 cultivars. The inflorescence morphology of regenerated
plant of ''Costume'' and ''Monami'' were significantly different
from stock plants, the regenerated plants of ''Red Small Mum''
callus were more variated on flower number, and ''Shiu Fang Chih
Li'' had more variation on petal numbers. The flower numbers,
flower diameter, flowering-node numbers, ratio of petal length
and width, and ratio of leaf length and width of 4 cultivars
had different variation, they resulted the various apperance
compared to stock plants. The flowers colour of 4 cultivars
were no significantly variations. Callus was stopped grow
after radiated by gamma ray. After continued subcultures, ''Shiu
Fang Chih Li'' callus which treated by 40 and 80 Gy could not
recover growth vigor, and browning to die. ''Shiu Fang Chih Li''
callus which treated below 20 Gy was paused to grow for 4
months, than began to proliferated and regenerate shoots. Most
of flower diameter of regenerated plants were small than stock
plants, and petals shape was irregular, lack of practical value.
Other cultivars radiated with gamma ray, the dose was below 20
Gy. All callus became brown and stopped growth. 7 months later,
surface of explants was formmed new callus and growth further,
but not regenerated buds yet.
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