Abstract

To evaluate effect of irrigation disruption 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 urmia, University (latitude 37.53°N, 45.08°E, and 1320 m above sea level), Urmia, Iran in 2010. Treatments, included irrigation (irrigation disruption at first, second, third harvest and without disruption as control) as main plot and amount of biological nitrogen (0, 3, 6, and 9 l/ha of nitroxin) as sub plot were arranged in randomized complete block design with three replications. Data analysis of variance showed the significant effect of irrigation disruption on area, length, width and weight of one leaf, specific leaf area (SLA) and Ratio of under/upper photosynthetic active radiation (PAR) of canopy. While the effect of biological nitrogen on area, and length of single leaf was significant. Interaction between irrigation and biological nitrogen on the ratio of under/upper photosynthetic active radiation of canopy and Leaf Area Index was significant, too. But, there were no significant effect of irrigation and nitroxin on the leaf proline content, leaf total soluble carbohydrate, chlorophylla, b, total chlorophyll, carotenoid, the leaf relative water content and Chlorophyll index (SPAD). Means comparison indicated that the maximum single leaf area (582.11 mm²), the widest leaf (0.99 cm) and the greatest single leaf dry weight (0.022 g), were obtained from plants grown under irrigation disruption at first harvest. The minimum single leaf area (476.14 mm²), the shortest leaf (3.72 cm) and the minimum leaf width (0.74 cm) were obtained from irrigation disruption after third harvest. The longest leaf (4.38 cm) and maximum specific leaf area (33449.1 mm²/g) belonged to irrigation disruption at second harvest and control treatment, and the smallest single leaf dry weight (0.018 g) and minimum specific leaf area (27465.2 mm²/g) was obtained from control treatment and irrigation disruption at first harvest, respectively. The highest single leaf area (841.829 mm²) and the longest leaf (5.66 cm) belonged to 9 l/ha of nitroxin application, and the minimum single leaf area (298.95 mm²) and the shortest leaf (2.67 cm) belonged to control treatment.

Key words: Calendula officinalis, chlorophyll, irrigation, leaf, nitroxin, osmolyte, water stress.