A rapidly increasing world population and the fast approaching geographical limitations of the world agriculture system have led to a serious consideration for a possible expansion of agricultural activities on to marginal lands which are unsuitable for plant growth and development. Among the main environmental stresses responsible for low productivity of crop plants on marginal lands are the salt and water stresses. Salinity is characterized by the presence of an abnormally high content of readily soluble salts, primarily chlorides, sulphates and carbonates of Na+, Mg2+, K+ and Ca2+. Consequently, these soils cannot be utilized for cultivating agricultural crops and medicinal herbs. NaCl is usually the dominant salt in the saline soils. Although physiochemical responses of crop plants to environmental stresses have been studied, relatively little is known about the performance of medicinal plants under these hardships.

          It was observed in this study that salinity caused by NaCl hampers growth processes of Cassia angustifolia and Cichorium intybus. Treatment consisting of 160 mM NaCl caused maximum growth reductions. Calcium resisted the stressful condition caused by salinity and minimized its deleterious effects on plant performance. Carbon and nitrogen assimilatory processes, viz. photosynthetic rate, stomatal conductance, contents of chl a, chl b, total chl, soluble protein and nitrogen in leaves, and nitrate reductase activity in the leaves, were also adversely affected by NaCl treatment applied at any phenological stage. Application of CaCl2 with NaCl mitigated the adverse effect of NaCl treatments. The nitrate content, on the other hand, increased in the NaCl-treated plants. The increase caused by NaCl and NaCl + CaCl2 treatments was almost equal but greater than one caused by CaCl2 alone in both the species studied.

          Proline content in the leaves increased with age of the plants irrespective of treatments. The increase was eight-fold and seven-fold against NaCl+CaCl2 treatments in C. angustifolia and C. intybus plants, respectively, as against a five time increase with NaCl treatments alone. It was enhanced by three and two times against CaCl2 treatments of the two species respectively. From these results it can be inferred that salinity induces accumulation of proline that might help in osmoregulation of the plant, and that proline in cells works as an osmolyte is proved by its increased accumulation with application of CaCl2 along with NaCl as both together create a more hypertonic soil environment giving way to more accumulation of proline.

          The sodium and chloride contents in the roots, stems and leaves increased with increasing NaCl level in the medium. Maximum accumulation occurred in the leaves; followed by stem and roots with each treatment of NaCl. The amount of Na+ taken up by the leaves was greater than the amount of Cl-. CaCl2 treatments reduced the sodium accumulation in different plant parts, but increased Cl- ion. Combined treatments mitigated the increased accumulation of sodium caused by NaCl treatments in both the species. Enormous accumulation of Na+ and Cl- ions in leaves suggests that these plants possibly act as ion accumulators and can be considered for being used to phytoremediate the degraded saline lands. On application of NaCl + CaCl2, the chloride content was higher than one against any of the two salts applied alone.

          NaCl stress had an adverse effect on potassium and calcium contents in roots, stems and leaves in both the species. The extent of decline was dose dependent. CaCl2 treatments were beneficial and increased the potassium and calcium contents at any stage of plant development. However, the reduction in the amount of these ions was less against combined treatments than against NaCl treatments. Elevated calcium mitigates the adverse effect of NaCl through inhibition of Na+ uptake and restores the adequate level of K+, and thus enhances the plant growth.

          Sennoside contents were maximum in pods of C. angustifolia followed by those in the immature leaves and mature leaves. The sennoside a, b, c and total sennoside contents in the senna plants decreased under high salinity effect, while supply of calcium promoted production of these substances responsible for the therapeutic property of the plant. Salinity of soil might alter the seed oil composition in chicory plants; the proportion of short carbon chain fatty acids decreased whereas long carbon chain fatty acids increased. This conversion was less with CaCl2 treatments, thus calcium playing a restorative role. Since the relative proportion of the component fatty acids changes in the seed oil, properties of the oil may also change. The efficacy of the given oil may thus be affected by the levels of soil salinity, meaning thereby that salinity-induced alterations in medicinal plants are not only quantitative but these may sometimes be qualitative too, thus affecting the efficacy of the plant drug.