Fenugreek (Trigonella foenum-graecum L.) is an important medicinal plant with great therapeutic effect. It is also a natural antioxidant source, it acts as anticancer, enhances insulin sensitivity and decreases serum cholesterol. The purpose of this study was to detect the effect of high temperature (35°C) and low temperature (15°C) on growth and some metabolic activities of fenugreek and to ascertain the role of putrescine in ameliorating the harmful effects induced by temperature stresses on fenugreek plant. The results show that both high and low temperature stresses significantly decreased growth, pigment content and total soluble protein. Proline, alkaloids, malondialdehyde and activities of some antioxidant enzymes (catalase, peroxidase and superoxide dismutase) were increased in response to heat stress. This suggests an important role of these compounds as self defense mechanisms of fenugreek plant against heat stress. The results also indicated that soaking fenugreek seeds in 5 mM putrescine for 2 hours before temperature stress enabled the plants to tolerate the injurious effect induced by temperature. The Transmission Electron Micrographs of heat stressed fenugreek leaves (35°C) showed some cellular abnormalities in chloroplasts, nucleus and intercellular spaces. Application of putrescine to the temperature stressed plant cells retained these organelles to their normal state.
Key words: Alkaloids; Antioxidant enzymes; Malondialdehyde; Pigment content; Plant growth; Pr‾ Putrescine; Temperature stress; Total soluble protein; Trigonella foenum-graecum.
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