ABA and SA showed different effect on stomatal closing on same condition. The addition of 1 mM salicylic acid to fully opened stomata resulted in a significant reductionn of 22 % in stomatal aperture. However, 1 mM ABA reduced 73 % of stomatal aperture. The light absorption spectra of the salicylic acid solution showed that SA was degraded within 1 hour. Therefore, SA solution was resupplied to the detached epidermis every 30 min. during incubation and it was found that even at 10 μM SA induced stomatal closing significantly. Its effect was also greatly pH dependent. The reduction of stomatal aperture caused by 1 mM SA was most effective at lower pH (pH 7.2, 5 %; pH 6.2, 40 %; pH 5.2, 78 %). Therefore, if SA was properly treated to the epidermal strips in the medium, the effects of SA on stomatal closing were similar with those of ABA.

The effect of growth regulators (NAA, BA and GA_3) and light (blue, red and far-red) on the changes in total protein and thylakoid membrane protein pattern of callus from intergeneric protoplast fusion between Nicotiana tabacum and Solanum nigrum were investigated. When the callus were irradiated with different wavelengths of light, blue and red light accelerated the synthesis of total proteins and thylakoid membrane proteins. Particularly, red light led to an increase in the protein synthesis compared to blue light. When the callus were subjected to various combinations of growth regulators, NAA+GA_3 and NAA-BA treatments induced remarkable increase of total proteins and thylakoid membrane proteins accumulation, particulary in the combination of NAA+GA_3 NAA+GA_3 treatment with irradiation of red light showed highest value in the accumulation of total proteins and thylakoid membrane proteins. We conclude that simultaneous application of red light and NAA+GA_3 treatment may induce synergistic effect in the synthesis of total proteins and thylakoid membrane proteins.