Effect of Spirulina and Brown Algae and Lead Levels on some Morphophysiological Characteristics of Ornamental Cabbage

Introdaction Heavy metals are one of the most important environmental contaminants, particularly in soil and water sources. Mining and metal mining activities are major factors in soil contamination and generally surface soil around mines contain high amounts of these metals. Lead (Pb) is one of the heavy metals and important pollutant in arid ecosystem. The use of plants to remove contaminated soil or phytoremediation is an economical method. Today, due to increasing the pollution of soil sources and resultant problems, identification of the resistant plant species against soil pollution is essential. Using lead-contaminated soils requires their decontamination and improvement. There are different methods to remove these pollutions, one of them is the use of phytoremediation to remove pollutants from water and soil or to reduce them. Among the plants that as an ornamental plant can have a covering role in the green space and also perform the work of phytoremediation is the ornamental cabbage plants (Brassica oleracea L.). In this regard, this study was conducted with the aim of investigating the effect of lead heavy metals and the use of brown algae (Polycladia indica) and spirulina (Arthrospira platensis) as biofertilizers on ornamental cabbage plants in the direction of plant treatment. In addition, due to the presence of polysaccharide compounds such as carrageenan and alginate in the cell wall, algae (seaweeds) have a higher ability to absorb many heavy metals. Materials and Methods The experiment was conducted as factorial based on a completely randomized design in 2020 at the research greenhouse of Zanjan University. The studied factors including lead from lead nitrate source Pb(No3)2 with three concentrations (0, 25 and 50 mg/kg) were applied to the potting soil in four replications in two stages with an interval of two weeks. The second factor was included no algae, brown algae (Polycladia indica) and spirulina (Arthrospira platensis), which occurred in four replications. The measured traits included morphological traits: number of leaves, leaf surface index. Wet and dry root weight, and physiological traits included total chlorophyll content, total leaf antioxidant, peroxidase enzyme, glycine betaine, malondialdehyde, and leaf lead and phosphorus content. Data analysis was performed using SAS software and means were compared by LSD method. Results The results of the variance analysis showed that different levels of lead and the application of