عنوان مقاله [English]
نویسندگان [English]چکیده [English]
Nowadays, the foliar application of some substances such as ascorbate and methanol is discussed in order to reduce the negative effects of various stresses. In order to examine the effect of these materials on defense mechanisms and seed and oil yield of Nigella sativa L., a split plot factorial experiment based on randomized complete block design was conducted with three replications at Shahrood University in 2011. The main factor was two irrigation levels (no stress and severe stress) and sub factors were foliar application of methanol in three levels (0, 15 and 30 %V) and ascorbic acid in three levels (0, 10 and 20 mM). The results indicated that seed yield was decreased by water deficit stress significantly. However, the increasing in methanol foliar concentration increased the seed yield in both stress and non-stress conditions. Methanol treatment in stress conditions was improved the amount of seed oil content considerably. The highest seed oil percentage was obtained from 8 days irrigation and 15 volume percentage of methanol. The water deficit stress conditions caused the highest activity of superoxide dismutase enzyme and the amount of malondialdehyde. Foliar application of ascorbic acid increased the content of ascorbate peroxidase and catalase enzymes nevertheless; hydrogen peroxide was decreased by this treatment. This is despite the fact that superoxide dismutase, malondialdehyde and hydrogen peroxide were reduced by methanol leaf application.