الفهرس 
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Abstract
This investigation was conducted in the Tissue Culture
Laboratory, Department of Horticulture, Faculty of Agriculture,
Moshtohor during the period from 1993 to 1996 to study the
possibilities of developing the micropropagation techniques for
stone fruit trees to cover the high demand for superior cultivars and
rootstocks of these plants in a short time.
Mother trees of apricot (Hamawy and Balady), peach
(Nemaguard and Okinawa) and almond (Ne Plus Ultra and Bitter)
were selected and indexed as free of known viruses. New growing
shoots were taken at the beginning of the growing season, washed
with running water, divided into small parts and immersed in an
antioxidant solution containing (150 mg/L. ascorbic acid and 100
mgIL. citric acid) for 20 minutes. The treated parts were sterilized
for 15 minutes using 10% Clorox (commercial bleach) plus two
drops of Tween-20, then transferred into sterilized distilled water
3-times for 5 minutes each. Shoot-tips (0.5 mm thick) were excised
from the teoninal parts, while the rest of these parts were divided
into one-node cuttings as explants under aseptic conditions. The
prepared explants were cultured on different media i.e. Murashige
and Skoog, Nitsch & Nitsch and Anderson. The used basal
medium was supplemented with 0.1 mg/L. IBA (Indole 3-butyric
acid), 1.0 mg/L. HAP (6-benzylaminopurine), 30 gIL. sucrose and
7 gIL. Difico Bacto agar for the establishment stage. However,
during the proliferation stage the same aforementioned supplementations
were added also to the used basal medium except BAP
which varied according to the treatment. In the rooting stage IBA
was only increased, but other constituents of the established
medium were used.
Generally, pH of the used medium was adjusted to be 5.7,
and autoclaved at 121°C and 15 Ib./in2 for 15 minutes: The
cultured explants were incubated under 16 hours of artificial light
(fluorescent light at 30 ~Mlm2/sec.) and 8 hours of darkness at
temperature of 28-30°C. Subculturing was done regularly at 4
weeks interval for all stages.
Anyhow, the obtained results can be summarized as follow:
7-1. Establishment stage :
1- Shoot-tips surpassed one-node cuttings in explant establishment,
and chlorophyll development along with reduced adverse effect
of necrosis in all stone fruit plants under study.
2- Solid Murashige and Skoog medium was superior in all measured
parameters for explant establishment and development. Anderson
medium was the poorest medium for apricots and peaches, while
Nitsch and Nitsch medium exerted an adverse effect on explant
development parameters of almond plants.
3- Antioxidant solution pretreatment succeeded in reducing the
accumulation of phenolic compounds as reflected in decreasing
necrosis of apricot, peach and almond explants. Moreover, the
combination of antioxidant solution as pretreatment and 300
mgIL. activated charcoal to the cultured medium took the
second rank in this respect.
4- Supplementation by 300 mgIL. activated charcoal to the medium
resulted in an adverse effect as it increased necrosis and
decreased sharply both explant and chlorophyll development.
5- One-fourth strength ofMurashige and Skoog medium improved
explant development parameters in apricot, while modified
Murashige and Skoog medium was preferred in this respect in
both peach and almond plants.
6- Explant establishment was greatly improved, while nicroses was
sharply less when adenine sulphate was added to the MS
medium followed by the use of coconut milk additive.
However, the reverse was true when MES hydrolysate was
added instead of adenine or coconut milk.
7-2. Proliferation stage:
1- Proliferation was enhanced when BAP was added to MS medium
in relation to kinetin, zeatin and thidiazuron.
2- Kinetin at 2 mgIL. improved growth and chlorophyll followed
by zeatin in relation to BAP.
3- The lower concentration of HAP (1 mgIL.) encouraged growth
and chlorophyll and caused less nicroses. However, using of 4
mgIL. BAP increased proliferation of either apricot or almond
plants, while only 2 mgIL. concentration induced the same
effect in peach plants.
4- The lower concentrations of thidiazuron (0.5 and 1.0 mg/L)”:
enhanced proliferation and the other growth criteria. However,
the higher concentrations (2.0 and 4.0 mg/L.) caused death of
plantlets.
5- The proliferation peak was reached after 28 days from culturing
time for apricot, peach and almond plants.
7-3. Rooting stage :
1- Shoot elongation was increased when 4.0 mg/L. GA3 was used
instead of lower concentrations (0.5 and 1.0 mg/L), where