effect of drought stress and organic fertilizer on activity of some antioxidant enzymes, photosynthetic pigments, proline and yield of borage (borago officinalis )

in order to study the effects of drought stress and organic fertilizers (compost and vermicompost) on some physiological and biochemical characteristics of borage, an experiment with complete randomized block design in split plot arrangement with three replications was conducted in zabol university, zabol, iran. the treatments included 3 levels of stress as a witness or 100% of field capacity, 80%field capacity(mild stress) and 60% field capacity (tension) as the main factor and use organic fertilizers, including control (nofertilizer), consuming 40 tons of compost per ha, and consumes 4 ton of vermicompost per ha, were considered as minor. results showed that chlorophyll index (spad) decreased with increasing severity of dehydration and the amount of chlorophyll fluorescence were added. the highest chlorophyll a (11.383 mg/g) in conditions stress and application of compost obtained and it was reduced with increasing stress intensity level and the lowest (5.763mg/g) in severe stress and lack of fertilizer application, respectively. the same trend was observed for total chlorophyll content. most of the enzymes catalase, ascorbate peroxidase and polyphenol oxidase in conditions of severe stress and lack of application and at least 100% of field capacity and compost application, respectively. proline at 60% field capacity and no application of any fertilizer (20.213 mmol/g wet weight) was a significant difference with other compounds treatments. drought stress affected the dry weight of the borage plant and cut it and dry yield (6.134826 kg/per ha) in the water level control was not a significant difference with mild stress (80% field capacity). overall production in drought conditions and the amount of enzyme scavengers, hydrogen peroxide and free radicals increases , then, in order to have acceptable performance of dry borage, crop irrigation to 80% capacity seems appropriate.