الفهرس 
m1;1ltipli" ~ "ation rate of some citrus rootstocks shoot:-tips in vitroOnly 14 pages are availabe for public view
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Abstract
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salt stress tolerance in vitro.
The results in the establishment stage showed that the removal of seed coats during sterilization
enhanced germination percentages in all rootstocks and enhanced the developmentt of seedlings. In
case ofmicropropagation, the results showed that both the physical ,na:tur<;: of the nutrient
medium and container type played an important role in the rate of proliferation. Jars gave
highest number of shoots, leaves and shoot lengths compared to test tubes. Also, the liquid nature
of medium gave high significant number of leaves compared to the solidified one. Rangpur lime
produced the highest significant number of leaves when cultured in jars, compared to.Volkmer lemon
and Sour orange rootstocks.
However, the solidified MS medium supplemented with lmgl-1 NAA gave the best rooting compared with
the liquid medium. Also; solid medium with lmgl-1 IDA was necessary for
1
root elongation in all tested rootstocks. Both RL and VO root tocks
proliferated the highest significant mean number of roots in the solid rooting medium with lmgl-1
NAA compared to the SO rootstock in both types of medium .
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Both systems of exposure to either constant or gradual
increasing concentrations of salts incorporated in solid or liquid medium caused salt injury
symptoms for citrus rootstock seedlings as it increased the average number of burned leaves
and shoot die
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back percentages espicially at high salt concentrations (6000-8000
ppm). The most affected rootstock after 4 or 8 and 12 weeks was SO followed with VO and RL, while
the least affected were CM and SC with or without significant differences. However, stimulation of
shoot proliferation and emergence of new roots were, also, significant in all salt concentrations
under the two regimes of exposure. RL rootstock recorded the highest number of proliferated shoots
and roots and, also, the highest length of shoots in most experiments under 2000, 3000 or 4000 ppm
after 4, 8 or 12 weeks respectively, followed by the SO while the lower values accompanied CM, SC
and espicially VO rootstocks. Similar results were obtained for both liquid or solid saline medium
except for the lower values recorded on growth parameters in solid medium and, also, the poor
response with VO rootstock Stem node cultures grew considerably better under salt concentrations
(4000-6000 ppm), without leaf burn or die back occurrence with the highest shoot length in C35
followed by SO and CM, respectively. Tolerant shoots were selected and acclimatized for 3 months
besides the continuous salt treatment (4000 ppm) before being successfully transferred to
glass-house conditions.