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A pot experiment was conducted to find out whether the foliar spray of salicylic acid (SA) could successfully ameliorate the adverse effects of salinity stress on periwinkle. Thirty-day-old plants were supplied with Control; 0 mM NaCl ? 10 -5 M SA (T 1 ); 50 mM NaCl ? 0 SA (T 2 ); 100 mM NaCl ? 0 SA (T 3 ); 150 mM NaCl ? 0 SA (T 4 ); 50 mM NaCl ? 10 -5 M SA (T 5 ); 100 mM NaCl ? 10 -5 M SA (T 6 ); 150 mM NaCl ? 10 -5 M SA (T 7 ). The plants were sampled 90 days after sowing to assess the effect of SA on stressed and unstressed plants. Salt stress significantly reduced the growth attributes including plant height, leaf-area index, shoot and root fresh weights, shoot and root dry weights. Increasing NaCl concentrations led to a gradual decrease in photosynthetic parameters and activities of nitrate reductase and carbonic anhydrase. Ascorbic acid, total alkaloids and antioxidants enzymes superoxide dismutase, catalase and peroxidase also declined in NaCl-treated plants. The plants, undergoing NaCl stress, exhibited a significant increase in electrolyte leakage and proline content. Foliar application of SA (10 -5 M) reduced the damaging effect of salinity on plant growth and accelerated the restoration of growth processes. It not only improved the growth parameters but also reversed the effects of salinity. Total alkaloid content was improved by SA application both in unstressed and stressed plants. The highest level of total alkaloid content recorded in leaves of SA-treated stressed plants was 11.1%.Foliar spray of SA overcame the adverse effect of salinity by improving the content of vincristine (14.0%) and vinblastine (14.6%) in plants treated with 100 M NaCl.

Artemisia annua L. is an aromatic-antibacterial herb that destroys malarial parasites, lowers fevers and checks bleeding, and of which the secondary compound of interest is artemisinin. Enhanced production of the artemisinin content in the whole plant is highly desirable. Keeping in mind, the importance of this valuable antimalarial plant, field experiments were conducted to investigate the effects of triacontanol alone and in combination with gibberellic acid on growth attributes, photosynthesis, enzymatic activities, essential oil and artemisinin content and yield of Artemisia. The results indicate that combination of triacontanol and gibberellic acid (1.5 mg l(1 '75 mg l (1 ) significantly increased activities of nitrate reductase and carbonic anhydrase by 25.9% and 21.5%, and net photosynthetic rate, stomatal conductance and internal CO 2 by 25.4%, 14.1% and 15.4% higher, respectively, when compared to unsprayed plants. This combined treatment also significantly enhanced artemisinin content and yield (29% and 61% higher values).

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