The investigation of adaptation mechanism of temperature and drought stress in physiological and biochemical levels in Ctenanthe sp. (Marantaceae)

SUMMARY In this study, the effects of temperature, drought and irradiation on the degree of leaf rolling, and the degree of stomatal opening during leaf rolling were investigated in Ctenanthe sp. {Marantaceae). The relationship between formation of the crystals on the leaves and these stresses was also examined. In addition, the effect of stress on the amounts of reducing sugar, the changes in soluble protein, in the amount of proline and protein profile in the rolled leaves were determined. For this purpose, the changes in the degrees of rolling and stomatal opening in the stressed leaves were studied respectively morphologically and anatomically. The composition of crystals was chromatographically analysed, and the amounts of reducing sugar, proline and soluble protein were spectrophotometrically determined. Apart from this, the effect of the stress on protein profile was analysed by SDS-polyacrylamide gel electrophoresis. The degree of rolling in the leaf was increased together with applications of temperature and drought. It was found that irridation stress alone was not effective on the leaf rolling, but it had synergistic effect with drought. In addition, it was observed that stomata remained open during leaf rolling. In the result of irrigation after leaf rolling, the crystals occured on the abaxial surface of the leaves and their composition was determined to have sucrose, glucose and fructose. According to control, the amount of soluble protein decreased and protein level weakened while the amounts of reducing sugar and proline increased in the rolled leaves. From these results, it can be suggested that there are two mechanisms which relieve the effect of stress in this plant. One of these is leaf rolling, a stress avoidance mechanism, and the other is osmotic adjustment, a stress tolerance mechanism. Key Words: Ctenanthe sp., Leaf Rolling, Stress, Stoma, Reducing Sugar, Proline, Protein VI