Microalgae have garnered significant attention as a promising source for biodiesel production due to their rapid growth, high lipid content, and minimal resource requirements. This study delves into the forefront of microalgal biofuel research by investigating emerging co-cultivation strategies aimed at optimizing biomass production for biodiesel synthesis. Through a nuanced exploration of diverse microalgal strains, this work pioneers innovative co-cultivation techniques designed to enhance synergies between different species, thus maximizing overall productivity. Microalgae are excellent options for the production of biodiesel since they have high lipid content and grow quickly. Nonetheless, difficulties in maximizing lipid and biomass production have led the technological advancement microalgal productivity using photobioreactors, closed systems and monitoring and genetic Engineering The article delves into the impact of Co-cultivation on microalgal growth such as improved Biomass production, enhanced lipid content and quality and nutrient utilization and recycling.

Background and Objective: This study was conducted to investigate the combined use of duck in different rice cultivation systems and effects on growth indices, photosynthesis and water productivity of fields. Materials and Methods: The experiment was carried out as a split plot factorial experiment based on randomized complete block design with three replications in Research Farm, Faculty of Agricultural Sciences, University of Guilan, in 2017 and 2018 years. Treatments included of three levels of cultivation system,Conventional cultivation (CC), Improved cultivation (IC) and SRI (System of Rice Intensification) as the main factor and combined of two levels of duck (control and 750 duck per hectare) and three levels of weed control (control, once and twice weeding) as factorials in sub-factor. Results: The results showed that the beginning of the growing period, all experiment treatments showed a significant difference in terms of leaf area index and with increasing the length of the growing period,the increase in leaf area index was greater in terms of combine treatments of 750 ducks per hectare and SRI. At the beginning of growth, CGR in SRI system was slower than the others and in the middle to late growth period, CGR rate values were in SRI>IC>CC. In un-use duck conditions, the rate of plant photosynthesis in all growth stages between once and twice weed control was almost not significantly different and the lowest values were assigned to the control, However, with the application of 750 ducks per hectare, no significant difference was observed between all levels of weed control in all terms of plant growth. In terms of application of 750 ducks per hectare, the highest yield of paddy was in SRI>IC>CC. In the conditions of application of 750 ducks per hectare, no significant difference in terms of irrigation water efficiency and rainfall was observed between different levels of weed control and the highest value were seen in the SRI. Conclusion: The experimental results showed the improvement of LAI and photosynthesis rate and increased of rice paddy yield and irrigation and precipitation water productivity due to the combined application of rice-duck in different cultivation systems. In general, the combined application of rice-duck in different cultivation systems can be considered suitable for improving the quantitative yield and growth and physiological indicators of rice to achieve sustainable agricultural goals and increase farmers' income per unit area in the plain areas of Guilan.

Aim: Nowadays, in the industrial areas, there is a problem of simultaneous contamination of soil with heavy metals and lack of organic matter that can impede the growth of plants. Thus, this study was done to investigate the effect of organic amendments on decreases plant abiotic stress in a soil cocontaminated with lead (Pb) and cadmium (Cd) under ornamental sunflower cultivation. Materials and Methods: Treatments consisted of applying vermicompost (0, 15, and 30 t/ha) and soil polluted with Cd (0, 5, 10, and 15 mg/kg soil) and Pb (0, 400, and 600 mg/kg soil), and the plant used in this experiment was ornamental sunflower. After 8 weeks of the experiment, plants were harvested, and soil and plant Zn and Fe were measured using the atomic absorption spectroscopy. In addition, the ascorbate peroxidase (APX) and peroxidase (POX) of the plant were measured. Results: The application of 15 and 30 t/ha vermicompost significantly depressed the APX and POX activity by 12. 1% and 14. 6%, respectively. While the plant Fe and Zn concentration was significantly increased by 11. 1% and 13. 6%, respectively. Increasing soil pollution to Cd to 15 mg/kg soil significantly increased the APX and POX enzyme activities of the sunflower by 14. 6% and 13. 3%, respectively. Conclusion: It can be concluded that the interaction effect of Fe and Zn with heavy metal can help to decrease the plant abiotic stress that is a positive point in the environmental research. However, the role of organic amendments in decreasing heavy metals availability cannot be ignored.