الفهرس 
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Abstract
In spite of the promising nutritive and medical importance of chicory (Cichorium pumilum), this species was underestimated and the information about its behavior particularly under the impact of salinity stress are scarce. Chicory exhibits seed dimorphism as it produces two forms of seeds; white and dark. There is a unique association between chicory and clover where chicory grows naturally as a weed within clover plantations and such a relationship is not observed with any other winter crop, therefore, the present study was planned to investigate the effect of salinity either as NaCl or KCl on germination of dimorphic seeds of C. pumilum, and the effect of association with clover during germination under salt stress. and also on growth, uptake of minerals and metabolism of the chicory plants emerging from the two seed forms This task was scheduled into a series of consecutive experiments as follows:
In the first experiment, white and dark seeds of chicory were germinated in NaCl or KCl at 0, 30, 100 and 250 mM for 7 days. The threshold salinity for germination capacity was 100 mM, beyond which NaCl exerted more toxic effect than KCl and white seeds had higher critical salinity
The second experiment was a brief test to determine the range of salt tolerance for chicory and clover during germination. White and dark chicory seeds and clover seeds were germinated either each seed form alone or in combination with clover seeds in two salt concentrations (0 and 250 mM) either as NaCl or KCl. Association between seeds chicory and clover had marked consequences on germination of both species.
The third experiment was more thorough investigation of the relationship between chicory and clover under salt stress during germination. As a compromise, a range of salinity suitable for both chicory and clover was chosen; that is 0, 25, 50, 90 and 130 mM either as NaCl or KCl. Despite of the intimate association observed between the two species, the relationship between chicory and clover during germination is not clear cut. Whereas association with clover seeds generally reduced germination of chicory seeds, association with chicory seeds improved germination of clover seeds.
We turned then to study the effect of salt stress on growth, ion uptake and distribution and metabolism of chicory during the vegetative stage. The two seed forms of chicory were grown under moderate range of salinity (0, 50, 100 and 150 mM) either as NaCl or KCl in peat moss. Vegetative chicory plants arising from dark seeds were more salt tolerant than those arising from white seeds and this was associated with:
a. Improved growth of dark seed-plants and no effect on white seed-plants by the threshold of 50 mM salinity.
b. Greater root to shoot dry weight ratio of dark seed-plants than that of white seed-plants
c. Stronger effect of KCl than NaCl on growth of dark seed plants, while the reverse was true for white seed-plants.
d. Preferential transport of K to shoot at the expense of its accumulation in root in dark seed-plants compared to white seed-plants
e. Limited transport of Na to shoot with greater capacity for its accumulation in root in dark seed-plants than in white seed-plants.
f. With consequently higher K/Na ratio in the foliage of dark seed-plants than in white seed-plants.
The biochemical characteristics of chicory leaves were profoundly and consistently affected by level of salinity, but the effect of type of salt and seed form was variable. Some measures such as protein content, peroxidase activity and the contents of carbohydrates and proline seem to be determined primarily by the genetic makeup of the plant (seed form) and less so by an environmental factor (type of salt). By contrast, some other measures such as catalase activity and the contents of phenolics and flavonoids are affected more by the environment with less variation between seed forms.