Private gardens and public landscapes in urban areas have always been formed by bedding plants,therefore, managing the negative impacts of drought on landscape is deemed vital. Urban areas in arid expanses of land are dealing with the abovementioned issue through landscaping systems that consume low amounts of water,nevertheless, data concerning tolerance against regulated deficit irrigation and the subsequent reactions of many plants, particularly ornamental species such as herbaceous perennials and annuals, are next to nonexistent. An annual specie, Calendula officinalis L. (Asteraceae), is used for its medicinal properties all around the world, it also goes by the name Calendula or marigold. This research was performed to find out and estimate the reaction caused by drought stress mainly at two different levels (100 and 50% FC) on 13 pots of marigold cultivars (Candyman Orange, Fiesta Gitana, Citrus Cocktail, Neon, Candyman Yellow, Fruit Twist, Sherbet Fizz, Oopsy Daisy, Pot Marigold, Greenheart Orange, Calendula Porcupine, Pink Surprise and Touch of the Red) with four replicates carried out in greenhouse environments. The morphological and biochemical responses/changes in characteristics of the plants in question were measured and analyzed at the final stage of the observation. Water stress (50% FC) lessened most of the assessed characteristics and raised proline content (P<0. 01). Traits attributed to flowers such as diameter and flower that were also studied decreased while the expected index maintained unchanged. Ultimately, Neon and Candyman, two quality designated cultivars, were shown to resist the conditions the most. On the whole, it was evident that the chief factor that had the impact on growth and the subsequent flowering of annual bedding plants was water supply,moreover, during drought, the quantity and quality of the species fell dramatically. Examining resistance response and the relevant characteristics attributed to the specie under investigation will contribute to the implementation of sustainable landscape systems which require less input.

The present study aimed to investigate the effect of application of organic fertilizers on the yield of medicinal plant, Calendula (Calendula officinalis L.). The experiment was conducted in a randomized complete block design with 10 treatments and 3 replications in the research farm of Zanjan University. Treatments included cattle manure, poultry manure, and vermicompost, each at three levels (5, 10, and 15 tons per hectare) and control (without fertilizer). The measured traits were the thousand seed weight, number of capitules per plant, leaf area, plant height, petal dry weight, capitule diameter, chlorophyll content index, flavonoids, carotenoids, and essential oil percentage. Data were analyzed by SAS software, and mean comparisons was performed by Duncan's test. The results showed significant effects of fertilizer on thousand seed weight, capitule number per plant, leaf area, carotenoids, and essential oil percentage at p£0.01, and plant height, petal dry weight, and flavonoid at p£0.05. The type of fertilizer had no significant effect on capitule diameter and leaf chlorophyll content. Overall, the results showed that using organic fertilizers had favorable impact on yield, growth characteristics, and active ingredients content of Calendula.

A pot experiment was carried out to determine the effect of foliage spraying of silicon (Si) on growth and ornamental characteristics of Calendula grown under salt stress and greenhouse conditions. A factorial experiment based on completely randomized design was conducted with 3 levels of Si (0, 50 and 100 mg/l) and 3 levels of NaCl (0, 100 and 200 mM) with 4 replications. At flowering stage, Si was applied with spraying two times in two week intervals. NaCl was also applied as drench (200 ml per pot) in two days interval. The results showed that salinity decreased the growth, SPAD values, flower number per plant and flower diameter. However, foliar applications of Si resulted in greater root, shoot and total dry weight, plant height and leaf area of Calendula plants under salt stress. The highest SPAD values were obtained under 100 mg/l Si application in all NaCl treatments. Salinity decreased number of flower per plant and flower diameter as ornamental characteristics; however Si increased them under salinity stress. Plants treated with 100 mg/l Si had the highest flower diameter at 100 mM of NaCl. Electrolyte leakage increased by salinity, however foliar application of Si significantly reduced electrolyte leakage under salt stress. These results suggest that the negative effects of salinity on the growth and ornamental characteristics of Calendula plants can ameliorate by foliar application of Si treatments.

The use of biological fertilizers and balanced plant nutrition as the most important soil fertility factors are among the main priorities of sustainable agriculture. In order to investigate the effect of biological fertilizers on some quantitative and qualitative characteristics of Calendula officinalis L., an experiment was done in the form of a completely randomized design with 14 treatments including (Azotobacter, Azospirillum, Pseudomonas, Thiobacillus, Azotobacter + Azospirillum, Azotobacter + Pseudomonas, Azospirillum + Thiobacillus, Azospirillum + Pseudomonas, Azotobacter + Azospirillum + Thiobacillus, Azotobacter + Pseudomonas + Thiobacillus, Azotobacter + Azospirillum + Pseudomonas, Azotobacter + Azospirillum + Pseudomonas + Thiobacillus, Pseudomonas, Thiobacillus, Thiobacillus + Azotobacter) and three replicates in the greenhouse of Nahavand Higher Education Complex in 1402. The results showed that the highest amount of phenol (1.86 mg GAE/gr) and flavonoid (5.54 mg routine/gr) was obtained in the combined treatment of Thiobacillus and Azotobacter. The highest stem diameter (17.48 mm) was produced in the combined treatment of Azotobacter and Pseudomonas. The highest diameter (15.19 mm) was created in Pseudomonas treatment. The highest height of the plant (28 cm) was produced with the use of Azotobacter biological fertilizer. The highest number of sub-branches, number of flowers per plant, fresh and dry weight of flowers were created in Azospirillum and Pseudomonas treatments. Finally, it can be said that the use of biological fertilizers, in addition to improving the quantitative and qualitative characteristics of Calendula officinalis L., is also an effective solution for achieving the goals of sustainable agriculture.

Application of Mycorrhizal Fungi (MF) and biochar can increase water and nutrient uptake in the rooting zone and thus improve crop production. A factorial experiment with completely randomized design with three replications was conducted to investigate the effects of biochar (0, 2 and 4% w/w) and MF (non-inoculation and inoculation with MF) on the morphophysiological characteristics and concentration of elements in Calendula (Calendula officinalis L. ) in greenhouse condition. The biochar was passed through a sieve of 2 mm and mixed with soil. The application of mycorrhizal fungi was done by direct contact with the root of plant. After six months, the morphophysiological characteristics and the concentration of some macro and micro elements in shoot were measured. The results showed that with simultaneous application of 4% biochar and mycorrhizal fungi increased chlorophyll, flower diameter, plant height, leaf area, stem diameter, plant dry weight and concentration of P, K, Ca and Fe compared to control, significantly. Zn concentration increased in 4% biochar treatment and simultaneous use of 4% biochar and mycorrhizal fungui compared to the control significantly (13. 7 and 19. 5% respectively). The application of 4% biochar caused a significant increase in Mn concentration compared to the control (91. 3 against 86. 6 mg. kg-1), while the application of 2% biochar has not a significant difference with control and 4% biochar treatments. The results of the effect of adding biohar to soil after plant growth period showed that available K, Ca, Mg and Mn increased with addition of 4% biochar by 22. 2, 18. 2, 43. 6 and 15. 2%, respectively. However, 2% biochar treatment had no significant effect on these soil parameters compared to control. It seems that application of these materials can improve availability of nutrients and plant growth parameters by improving plant growth conditions and affect crop production...