Effects of PEG-induced drought and salt stress on germination characteristics, changes in proline, carbohydrates and antioxidant enzymes in three Varieties Of Plant Medicine

fatemeh mesri¹ sajede saber²

1) Master of Agriculture , University of Zabol
2) Master of Chemical Analysis , University of Zabol

Publication : 4th International Congress of Developing Agriculture, Natural Resources, Environment and Tourism of Iran(4icsda.ir)
Abstract :
A factorial experiment was done in completely randomized design with 3 replications in order to evaluate the tolerance to drought and salinity stress in three cultivars of medicinal plants and classify the components of germination in terms of sensitivity to both stresses. Treatments include the cultivars at 3 levels (Foeniculum vulgare, Hibiscus Sabdariffa, Cynara scolymus) and drought treatment at 4 levels (including control, 5, 10 and 15 dS/m) and salinity treatment at 4 levels (including control, 100, 200, and 300 mM of sodium chloride). Obtained results of data analysis indicated that the effect of drought and salinity on tested characteristics of cultivars was significant at 1% level. Furthermore, a number of traits including germination rate and percentage, root length, stem length, total dry and wet weight, salt showed a decreasing trend through increasing the levels of drought and salinity; and the osmotic adjustment, proline and carbohydrate were gradually increased in ground and aerial organs as the result of enhanced drought; however, this increasing trend was also observed in salinity stress, so that the minimum value was related to the control level and the maximum level related to the highest level of drought and salinity. Moreover, investigation of enzymatic changes in both ground and aerial organs indicates their increase in salinity and drought stress conditions. In general, the Hibiscus Sabdariffa cultivar led to more appropriate responses compared to the drought stress (especially severe stress) in order to be protected from damages, but the Hibiscus Sabdariffa cultivar was a relatively sustainable cultivar under salinity stress condition and Foeniculum vulgare cultivar was the most sustainable cultivar under salinity stress condition. Cynara scolymus cultivar was relatively sustainable under drought stress condition and the most sensitive cultivar compared to other applied cultivars under the salinity stress condition. Foeniculum vulgare cultivar was considered as the most sustainable one under the salinity stress condition and the most sensitive cultivar under drought stress condition.
Keywords : Proline- Carbohydrate- drought stress- salinity stress- osmotic adjustment