Document Type : Research Paper
Authors
1 MSc. Student, Deparment of Agronomy and Plant Breeding, Faculty of Agriculture Science, Shahed University, Tehran, Iran
2 Deparment of Agronomy and Plant Breeding, Faculty of Agriculture Science, Shahed University, Tehran, Iran
3 Deparment of Soil Sciences, Faculty of Agriculture Science, Shahed University, Tehran, Iran
Abstract
To investigate the effect of drought stress and bio-fertilizer (nitrogen) on flower yield, yield components, photosynthesis pigments and proline content of Calendula (Calendula officinalis L.), a study was performed at Shahed University Agricultural Research Station, located 30 km south of Tehran. A split-plot experiment was conducted in randomized complete block design (RCBD) with three replications in cropping years of 2010-2011. Drought, as the main factor, included soil water potential (SWP) of 0.5 atm and equal to field capacity (FC) as control, SWP of 3.5 atm as moderate stress, SWP of 6.5 atm as relatively sever stress, and SWP of 10 atm as severe stress and was applied to the four-leaf stage. Application of bio-fertilizer (nitrogen) as sub factor including control, 2 liters/ha bio fertilizer (nitrogen) with water irrigation and inoculation of 2 liters/ha bio-fertilizer (nitrogen) with seed treatment), were considered in subplots. Results showed that drought, application of bio fertilizer (nitrogen) and its interaction had a significant effect (P≤0.01) on plant height, flower yield, photosynthesis pigment content, proline content, and flower extract percentage. The highest flower yield (574.46 kg.ha-1) and yield of flower extract (22.79 %) were obtained at a soil water potential (SWP) of 0.5atm (FC). Also, the highest plant height (27.11cm) and photosynthesis pigment contents (17.59 mg/g) were obtained under moderate stress (SWP of 3.5atm). Proline content under optimum irrigation (SWP of 0.5atm or FC) was 47 % lower than that of relatively severe stress (SWP of 6.5atm). Based on the results, the highest plant height, flower yield, proline content and yield of flower extract were obtained from inoculation of bio-fertilizer (nitrogen) with seed treatment. In generall, results showed that calendula along with application of two liters/ha bio-fertilizer (nitrogen) with seed inoculation can tolerate relatively severe levels of drought (SWP of 6.5 atm).
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