الفهرس 
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Abstract
Dendranthema x grandiflorum is a dominant species of the Dendranthema genus for the
inducing of callus cultures. Explants such as leaves and internodes were employed in this
study to see how various types of explants, as well as regulators of plant growth at varying
levels, affected callus induction. According to results of the percentage of formation callus,
fresh and dry weight characteristics, the explant of leaf considerably boosted callus induction
over the explant of internode. After two months of cultivate, MS supplemented with 0.2 mg/l1
6-BAP and 0.5 mg/l-1
2,4-D produced the highest efficient induction of callus. In
comparison to 6-BAP 0.1 mg/l-1
, 6-BAP 0.2 mg/l-1
significantly increased callus induction in
both fresh and dry weight metrics. Although there were no significant differences between the
0.5 mg/l-1 2,4-D treatment and the 1 mg/l-1
2,4-D treatment for fresh weight, the high 2,4-D
levels 2 mg/l-1
also performed significantly better than the lower levels for dry weight.
Likewise, the control that was free of 2,4-D yielded the lowest weight, both fresh and dry. For
fresh weight, 0.5 mg/l-1
2,4-D leaf explant outperformed all other treatments except internode
explant, whereas for dry weight, 2 mg/l-1 2,4-D explants of leaf outperformed all other
treatments than explants of internode. Likewise in both concentrations (0 and 0.5 mg/l-1
), the
control of leaf and internode explant provided the lowest weight fresh, but the control of leaf
explant yielded the lowest dry weight. All other treatments for fresh weight were
outperformed by 0.1 mg/l-1
6-BAP with 0.5 mg/l-1
2,4-D and 0.2 mg/l-1
6-BAP with (0.5, 1,
and 1.5 mg/l-1
) 2,4-D, but 0.1 mg/l-1 6-BAP with 0.5 mg/l-1
2,4-D was the best. The control
treatment, which was devoid of regulators of plant growth, yielded the lowest fresh weight. In
term of dry weight, the combination of 0.1 mg/l-1
6-BAP and 2 mg/l-1
2,4-D leaf explant
outperformed all other treatments. The control treatment yielded the lowest dry weight.
The two-month-old calluses of Dendranthema x grandiflorum on MS supplement with
0.1 mg/l-1 NAA, 0.2 mg/l-1
6-BAP and 0.5 mg/l-1
2,4-D were acute subjected with 0, 2.5, 5,
and 7.5 Gy X-rays radiation. The highest value of organogenesis percentage (90 %) was
observed on control which was not subjected to X-rays. The minimum organogenesis
percentage was observed on 5 Gy (36.27 %). The use of 2.5 Gy excelled all other treatments
for number of shoots (34.20), length of shoot (2.36 cm), branches number (2.60) and number
of leaves (20.80). The least shoot length (0.62 cm), number of branches (0.40), and leaves
number (10.40) were obtained from the 5 Gy, but the least value number of shoots (25.60)
was recorded from control. The highest shoot length, roots length and roots number/shoot
(6.48 cm, 6.32 cm, and 10.40 respectily) obtained from 2.5 Gy. The lowest shoot length, roots
length and roots number/shoot (3.20 cm, 4.04 cm, and 5.40 respectily) were obtained from 5
Gy, although it did not differ significantly on roots number (6.60 and 5.40) from the control
and 5 Gy. The highest survival percentage (100%) was obtained from all different doses of Xrays treatments. The best results for shoot length (10.38 cm) and leaves number (12.40) were
recorded on exposure 2.5 Gy, although it did not differ significantly on leaves number (10.40
and 10.00) from 5 Gy and the control. In addition, both of the control and 2.5 Gy did not
differ significantly on roots length (6.45 and 5.84 cm respectively) and shoots fresh weight
(0.540 and 0.668 g respectively). Similarly, the best results of Chl a, total chlorophyll and
total carotenoids were obtained from 2.5 Gy (11.84, 16.35, and 4.25 mg/g FW respectily)
although it did not differ significantly from the control.
This indicates that there are no genetic differences, which means that there is genetic
stability with the use of radiation. The radiation to have affected the amount of DNA inside
2.5 Gy, resulting in a clear reduction in the density of the size of the bands.