effect of salinity stress and iron spraying on leaf area index, light absorption and relations with yield in sunflower (helianthus annuns l.)

salinity stress results to decreasing leaf area index (lai) and light absorption in plant leading in yield decrease. in order to study effect of salinity and iron sulphate on lai, absorbed light percentage and yield of sunflower (euroflor cultivar), an experiment was carried out as split plot based on complete randomized block design with four replications in the research field of university of birjand on 2009. in this experiment main plots were different levels of irrigation with saline water and subplot was levels of iron sulphate. results showed that with decreased lai and light absorption, yield was negatively responded to salinity. one way for recovery of light absorption in salinity condition is spraying iron sulphate. the highest light absorption percentage up to 70.34% was obtained in control condition with the lai of 3. in this condition yield of sunflower was 4250 kg/ha. iron sulphate spraying reduced the negative effects of salinity on lai.