Effect of increasing severity of drought stress on leaf physiologicaland morphological characters in Calendula officinalis L.

摘要

To evaluate effect of water deficit stress on some physiological and morphological characters of Calendula officinalis L., an experiment was conducted as split plot at the Research Farm of Faculty of Agriculture UrmiaUniversity (latitude 37.53°N, 45.08°E, and 1320 m above sea level), Urmia-Iran in 2011. Treatments were irrigation (irrigation after 30, 60, 90 and 120 mmevaporation from classApan) as main plots and gradual rise intensification of water deficit (increasing the irrigation intervals after first irrigation cycle amounted 0, 5, 10 and 15 mm evaporation) as sub plots. Data analysis of variance showed the significant interaction between irrigation and stress strength on single leaf area, leaf width, length and weight,, the number of leaves per plant, leaf area index (LAI), specific leaf area (SLA) and leaf area ratio (LAR). Means comparison indicated that the maximumsingle leaf area, leafwidth, length, dryweight, the number of leaves per plant, LAI, SLAand LAR (38.14 cm2, 3.32 cm, 13.24 cm, 0.22 g, 13.24, 3.26, 85.82 cm2/g, 19.37 cm2/g, respectively) were obtained from irrigation after 30mmand control treatment ofwater deficit strength (0mm evaporation). The maximumproline (0.01 mg/l) and soluble carbohydrate (0.52 mg/l) were obtained fromirrigation after 120 mmevaporation as the most sever water deficit stress.