الفهرس 
Material and methodsOnly 14 pages are availabe for public view
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Abstract
v- SUMMARY & CONCLUSIONS
This study was carried out in the Tissue Culture Lab,
Hor. Dept, Faculty of Agric., Mosthtohor during the period
1990-1992. The objective of this study was to find out the
best microprogagation techniques for overcoming the problem
of high demand for healthy highly productive coffee plants of
known cultivars.
The retarding factors for further development of the
used explants were studied either by the determination of
phenolic compounds in both explant and medium or through
histological studies for developmental stages of somatic
embryogenesis.
Furthermore, multiplication of the resulted plantlets
was concerned. The results can be summarized as follows :
1- Inhibitor materials :
1- The leaf disc explant had the highest level of phenolic
compounds either before or after pretreatment with
antioxidant solution while internode segment was the least
in this concern.
2- The rate of reduction in phenolic compounds was very high
when leaf disc explants were used while an opposite trend
was shown in the case of internode segments.
3- The rate of accumulation of phenolic compounds in the
culture medium was almost similar at the end of establishing
period for all used explants.
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4- Callus contained very low content of phenolic compounds
which decreased gradually by the time up to the lowest
content after 8 weeks from cUlturing time.
5- Accumulation of phenolic compounds in the callus culture
medium was very low.
6- Antioxidant treatments is critical for micropropagation of
~ arabica explants.
7- There were a negative relationship between necrosis and
further development of the cultured explant.
8- The combination of antioxidant solution, 3 gm/L activated
charcoal and 40 mg/L L-cysteine treatment, was effective
in decreasing necrosis and encouraging both callus production
when leaf disc or internode segment explants were
used and enhanced plantlets regeneration when apical
meristem or single node cuttings were used.
9- Charcoal is valuable either alone or combined with any
other antioxidants in reducing necrosis and encouraging
either callus production or plantlets regeneration.
11- Somatic embryogenesis
1- Leaf discs were the best explants of coffee giving the
highest callus production.
2- 2,4-D surpassed any other auxin used in callus production.
3- The highest concentrations of auxin and kinetin are very
important for encouraging callus production (1.0 & 2.0
mg/L 2,4-D combined with 1.0 mg/L kinetin) .
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4- Induction and development are dependent on callus type as
friable callus can not develop into somatic embryos while
globular callus develops successfully.
5- 200 mg/L casein hydrolysate enhanced induction of the
highest number of somatic embryo.
6- Malt and yeast extracts failed completely in encouraging
the induction of somatic embryogenesis.
7- Higher kinetin concentration (0.5 mg/L) in COmbination
with casein hydrolysate induced the highest somatic
embryogenesis.
8- Developmental stages of somatic embryogenesis are directly
related to callus colour and age.
9- The number of somatic embryos
callus age as the older and dark
highest number of somatic embryos.
10- The number of lobes multiplied every 2 weeks while the
number of somatic embryos per lobe is some what constant.
11- The somatic embryo has 3 stages starting after 3-4 weeks
from culturing time with globular embryo, forming heartshaped
embryo after about 2 weeks which finally developed
into turpedo shaped embryo after 8-10 weeks from culturing
time.
12- Proliferation of somatic embryo took place after 6-8
were closely related to
brown callus gave the
weeks from culturing time.
13- 20 ml/L coconut milk combined with 0.1 mg/L GA3, 0.1 mg/L
kinetin and 1 mg/L NAA enhanced plantlets regeneration
from well developed somatic embryo when added to
Murashige & Skoog medium.
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14- The number of well developed embryos were abundant while
only few of them developed into plantlets.
III- Microcuttings propagation :
1- IAA is the most effective auxin in inducing large number
of regenerated plantlets.
2- Single node cuttings surpassed apical meristem in number
of regenerated plantlets
3- Increasing the concentrations of auxin was most effective
in increasing number of regenerated plantlets.
4- Combination of auxins and 6-benzylaminopurine was very
important in encouraging plantlets regeneration.
IV- Proliferation :
1- The higher concentration of 6-benzylaminopurine up to 8
mg/L encouraged the largest number of plantlets.
2- The combination of 6-benzylaminopurine with 0.5 mg/L IAA
produced the best results of proliferation.
3- 6-benzylaminopurine surpassed kinetin in increasing the
multiplication of coffee plants.
It could be concluded that leaf disc explant contained
the highest level of phenolic compounds while internode segments
contained the lowest level as compared with apical
meristem and single node cuttings. Phenolic compounds decreased
in different explants but the reverse was true as the
culture medium was concerned. The best treatment for reducing
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the content of phenolic compounds and in turn leads to reducing
necrosis was the combination of antioxidant solution
pretreatment together with 3 gm/L activated charcoal and 40
mg/L cysteine in the medium.
Leaf disc explant was found to be the most suitable
explant for callus production, induction and development of
somatic embryogenesis of coffee plants. Also, 2,4-D with
higher concentrations (1.0 & 2.0 mg/L) was suitable for large
callus production. Casein hydrolysate proved to be excellent
organic additive for induction and development of somatic
embryos.
Callus coloures changed in relation to development of
somatic embryogenesis stage. Globular embryo appeared after 4
weeks from culturing, then developed into heart-shaped and
finally to turpedo-shaped somatic embryo after 8-10 weeks
which regenerated into plantlets.
The best plantlets regeneration was obtained when single
node cutting was used as explant and 1.0 mg/L IAA combined
with 1.0 mg/L BAP were added to the media. In the same time,
higher concentrations of BAP combined with 0.5 mg/L lAA
encouraged the best proliferation of coffee plantlets.
The most important problem in this investigation is that
although large number of somatic embryos were induced and
developed but most of these embryos failed to regenerate into
plantlets which require further study to regenerate a whole
plant.