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Plant responses to multiple environmental conditions in the habitat are characterized by intra-species variety. Ferula assa-foetida L. is a native medical plant in Iran, which has a wide range of therapeutic and pharmacological properties. The objective of the current study was to identify changes in phenolic content, antioxidant capacity and essential oil (EO) composition in different tissues (leaf, flower and fruit) of three populations of F. assa-foetida L. (Sarbisheh, Nehbandan, located in South Khorasan province of Iran). The results showed that total phenolic content (TPC), total flavonoid content (TFC) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity in the leaves of Sarbisheh were higher than in other treatments. The amount of TPC, TFC and DPPH scavenging activity in leaves was higher than in other tissues in the Sarbisheh population, increasing by 31 and 70%, 41 and 20%, 8 and 13%, respectively, over that of flowers and fruits. The main EO compounds of leaves were α -pinene (11.86–13.56%), β -pinene (6.80–7.99%), bornyl acetate (15.80–17.33%). The main EO constitutes of flowers were Z-propenyl-sec-butyldisulfide (10.12–12.4%), eco-fenchyl acetate (10.87–12.4%), myrcisticin (13.43–15.87%) and α -bisabolol (11.23–13.76%). The primary compounds of fruit EO were β -pinene (9.32–11.26%), (Z)-1-propenyl sec butyldisulf (17.54–18.87%) and (E)-1-propenyl sec butyldisulf (28.32–30.02%). The agglomerative hierarchical clustering showed that three distinguished clusters were identified for population, where Nehbandan and Qaen had the higher similarity and Sarbisheh completely differed from the two ones. Different plant tissues contain varying types of chemicals, with leaves exhibiting higher levels of phenolic content and antioxidant capacity. This characteristic can be beneficial for industries such as food and pharmaceuticals. [ABSTRACT FROM AUTHOR]

This work was carried out to study the effects of water deficiency stress, different levels of nitrogen application, and plant population on Water Uptake Efficiency and Nitrogen consumption of oily sunflower. It was conducted at West-Azarbaijan's Research Center for Agriculture during 2008 and 2009. The study consisted of split-split-plot experiments using Randomized Complete Block Design with three replications. The main factor was considered to be irrigation treatments including optimum irrigation, moderate stress and severe stress in which irrigation was done after depletion of 50%, 70% and 90% of field capacity, respectively. Three nitrogen levels of 100, 160 and 220 Kg N ha-1 were considered as sub plots with sub -- sub plots consisting of three plant population of 5.55, 6.66 and 8.33 plant m-2.The combined variance analyses indicated that water deficiency stress, nitrogen and plant population have a considerable impact on grain and biological yields, seeds per head, head diameter, kernel percentage to seed, 1000-grain weight, plant grain yield and harvest index. The maximum grain yield (4200 kg/ha) was attributed to optimum irrigation treatment. Severe drought stress reduced the grain yield by 44% compared to the optimum irrigation condition. Grain yield increased at higher nitrogen application rates. The response of grain yield to increase in plant population was positive. All yield components were affected by the changes in plant population. The harvest index decreased with increasing severe drought stress and plant population. According to the results obtained in this research, application of 220 kg N ha-1 and larger plant population in optimum conditions and moderate drought stress is recommended for suitable yield, although an increase in nitrogen consumption and plant population has a little impact on grain yield in severe drought stress conditions. [ABSTRACT FROM AUTHOR]