الفهرس 
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Abstract
The present investigation aimed to produce callus from hypocotyl and try to increase main active ingredient (silymarin) in callus under salt stress. Four experiments in vitro conducted between 2012 – 2014 in tissue culture lab. in Botany Dept., Fac. of Agric., Ain – Shams University, Shobra El – Khima, Cairo, Egypt.
A number of plant growth regulators i.e NAA (Naphthalene acetic acid) and BA (Benzyle adenine or Benzyl amino purine) as well as NaCl and MS (Murashige and Skoog) components levels were used at different concentrations in vitro. Callus samples were take for growth pearameters (F.W., D.W. and growth index), succulence, salt tolerance index, silymarin and proline concentration.
The results obtained from the previous studies could be summarized in the following:
I. The Frist Experiment
Callus induction
1. All combined treatments between NAA and BA led to a significant increase in fresh and dry weights, and growth index.
2. The maximum value of growth parameters (F.Wt., D.Wt. and growth index) were recorded by T5 (NAA at 0.75 ppm + BA at 0.1ppm) and T6 (NAA at 1.0 ppm + BA at 0.1 ppm) treatments.
3. The highest values of silymarin concentration were observed by T5 (NAA at 0.75 ppm + BA at 0.1ppm), T6 (NAA at 1.0 ppm + BA at 0.1 ppm) and T8 (NAA at 0.75 ppm + BA at 0.125 ppm).
II. The Second Experiment
1. germination % of Silybum marianum L. seeds was strongly affected by the most salt treatments.
2. Generally, with increasing salinity stress levels, radical length significantly decreased.
3. NaCl treatments at 5000 ppm alone or combined with MS medium components exhibited the lowest reduction in radical length (1.33 – 0.5 cm) compared to control level (3.67 cm).
4. Hypocotyl length was more sensitive than radical length and under increasing salt stress level, hypocotyl length significantly were decreased with all treatments.
5. The high salinity level (NaCl and / or MS components) gave the maximum values of hypocotyl thickness.
III. The Third Experiment
1. The combined treatments of NAA and BA (T5 and T6) without salinity significantly increased fresh and dry weights, and growth index as compared to the rest treatments with salinity.
2. The minority of previous growth parameters was due to the lowest level of Nacl (3000 ppm) as compared to the other salinity treatments (4000 and 5000 ppm) and without salinity (T5 and T6).
3. The maximum value of succulence was showed by combined treatments of NAA and BA without salinity.
4. The results indicated that the increase in salt tolerance index are related with the level of salinity.
5. The combined treatment between NaCl at 3000 ppm plus T5 or T6 gave the highest significant values in silymarin concentration comparing with the rest treatments.
6. Increasing NaCl concentration increased the proline accumulation. Proline concentration are associated with the level of salinity.
IV. The Fourth Experment
1. A significant decrease in fresh and dry weights, and growth index by all combined treatments between NaCl and MS components levels as compared to the control (T5 treatment).
2. In general, NaCl combined with full components of MS and NaCl at 3000 ppm with one plus half MS had promotion effect on fresh and dry weights, and growth index comparing with the rest treatments.
3. A significant increase in succulence was noticed by NaCl at 3000 ppm combined with one plus half MS and NaCl at 4000 ppm combined with half and double MS .
4. Combined treatment of NaCl with three levels plus full components of MS gave the highest salt tolerance index values when compared to the rest treatments.
5. NaCl at 3000 and 5000 ppm with full components of MS had the highest significant values in silymarin concentration comparing with control and the rest treatments.
6. There were a significant increase in proline concentration by increasing salinity and MS levels.
The isomeric flavonolignans found in control treatment (without plant growth regulators) were SC and ISBB. The isomers of flavonolignans in T5 and T6 treatment were SC, SBA and ISBB. These data suggest that the conjugated SC, SD and ISBB are the metabolites in T8 treatment. Conjugated ISBA and ISBB as the metabolites are presented in combined treatment NaCl at 3000 ppm with T6.