الفهرس 
REVIEW OF LITERATUREOnly 14 pages are availabe for public view
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Abstract
This study was carried out in plant Tissue Culture Laboratory at desert research center during the period from 2006 to 2009. The goal of this study was to establish a protocol for plantlets formation from peach rootstocks by using micropropagation techniques. Also, evaluation tolerance ability to the salinity stress. Generally, the following experiments were carried out.
Hence, it was hoped to find out an ideal method as true propagation for providing with the adequate quantities of nursery transplants of this desired rootstock to meet the increasing demand due to its advantages, especially under the new reclaimed area condition. So, some treatments dealing with the various stages of direct regeneration through tissue culture technique i.e, establishment; proliferation; rooting and acclimatization were initiated.
In addition, salinity tolerance of these rootstocks was investigated explants (shoot tip and stem segment) for Nemaguard peach Rootstocks, and bitter almond were taken in March and subjected to running water + soap for hour. Then sterilized by using (1 – 1.5 and 2 %) Chlorox (commercial bleach) with two DROPs of Tween-20 for 15 minutes were investigated regarding their influence on contamination and survival % during this stage was studied .The explants were cultured on different types of media.
Data were recorded from culturing. Cytokinins type and BA, Kin concentrations, medium strength, GA3 concentration, auxin type IBA and NAA concentrations and activated charcoal (AC) were evaluated during proliferation, elongation and rooting stage.
Different levels of salinity was caused by adding NaCl and CaCl2 (ratio, 2:1) (1000, 2000, 3000, 4000, 5000 and 6000 ppm) to the culture medium.
The obtained results can be summarized as follows:-
5. 1. Establishment stage:
1- Murashige and skoog showed the most superior medium for increasing explants development in most tissue culture technique for both bitter almond and Nemaguard peach root stocks.
2- Shoot tip showed the best explants than stem segment in Nemaguard peach rootstock.
3- Sterilization method by using 2% of Chlorox gave the highest survival percentage in bitter almond, while gaves 1.5% lower contamination percentage.
5. 2. Multiplication stage:
1- BA was the best cytokinin enhancing proliferation in Nemagurd peach and bitter almond rootstocks while kinetin was effective in improving growth and greening parameters of bitter almond
2- Using Full strenght of Murashige and Skoog was the best in greening plant for both bitter almond and Nemaguard peach rootstocks.
3- Kin. In the first failed to subculture one not appear any result, while, in the second subculture was affected with different strength in bitter almond.(stem segment).
5. 3. Shoot elongation:
1- Shoot elongation of bitter almond rootstock was increased by using free media (without hormone).
2- Adding 0.1 mgL-1 of GA3 to the culture medium enhanced shoot elongation of Nemaguard and bitter almond peach rootstock, while using of 0.5 mgL-1 GA3 was preferred for bitter almond rootstock embryo.
5. 4. Root formation:
1- Indole-3-butyric acid was the most effective auxin as it enhanced rooting of both Nemaguard peach (prunus persica) and bitter almond (prunus amygdalus) rootstocks.
2- In addition, high concentration of IBA (2.0 mgL-1) maximized rooting of bitter almond rootstock while 1.5 mgL-1of IBA was the best for Nemaguard peach rootstock. Both of them were free from activated charcoal.
3- Using half strength of MS medium produced the best root formation comparing with the other media strengths.
5. 5. Salinity tolerance:
1- The adverse effects of salinity on tissue culture parameters of both peach rootstock appeared greatly under higher concentrations of NaCl + CaCl2.
2- Using NaCl + CaCl2 at concentrations higher more than 2000 ppm induced a bad effects on all parameters under study up to the lethal concentration which caused by 3000 ppm Salinity which caused almost death of the In vitro plantlets for nemaguard rootstocks. whereas, Salinity at 2000 ppm had a bad effect on the plantlets in vitro of Nemaguard rootstock.
3- The elements contents K+, Na +, Fe++, and Zn++ were gradually increased with increasing NaCl + CaCl2 levels in both rootstocks (Nemaguard and almond). In addition Nemaguard accumulated more K+ and Na+ than almond. Also, ionic content of (Fe++ and Zn++) increased with increasing level of NaCl + CaCl2 in the media. But the Fe++ ions at 1000 ppm of salt was highest for Nemaguard .whereas, bitter almond was recorded the highest Fe ++ at 3000 to 6000 ppm of NaCl + CaCl2 with value of (2.5 mgL 1). However, the results indicated that bitter almond peach rootstock tolerated NaCl higher than bitter almond.
5. 5. 1. Response of peach rootstocks Rooting formation to a gradual increase in salt stress:
1- Bitter almond rootstock showed the highest survival they were exposed gradually to high salinity levels.
2- All in vest gated peach rootstock showed a progressive reduction in survival percentages in comparison to those of un treated control by increasing the salinity levels in the media up to 6000 ppm NaCl + CaCl2 (ratio 2:1).
3- All peach root stocks that were transferred gradually to media containing sequent salt concentration showed less fresh weight than control plantlets.