Turfgrass is one of the basic and essential elements in order to decoration of environment that must be cultivated using new methods due to high costs of planting, maintenance, high water requirements, and climate incompatibility. Sport turfgrass is a mixture of different turfgrass seeds with variable proportions for use in different applications, which is currently being exploited due to its better compatibility with planting environments. Since environmental stresses, especially salinity stress, can lead to destructive effects on growth and developmental stages of this plant, the use of stimulants like elicitors and nanoparticles can reduce the side effects of salinity stress through increasing the resistance of plants. Chitosan nanoparticles are known as defense stimulants and play a key role in defense reactions under stress conditions by changing membrane permeability, increasing the production of antioxidant enzymes activities, secondary metabolites production as well as improvement of qualitative and quantitative traits. Also, the use of biochar as an organic amendment in soil can not only help increase organic matter in the soil, but also moderate the adverse effects of salinity in plants.



Materials and Methods

This project was conducted based on completely randomized design with three replications at greenhouse of Sana Institute of Higher Education, Sari, Iran in 2024-2025. The treatments contained chitosan nanoparticle in three level (0, 0.2 and 0.4 g/L), biochar in three levels (0, 2, and 4 % w/w), and salinity in three levels (0, 25, 50, 75, 100, and 125 mM). some morphological and physiological traits was analyzed such as total fresh weight, total dry weight, leaf tissue, monotony, density, photosynthetic pigments content and antioxidant enzymes activity. The obtained data was analyzed by SAS software version 9.4 and the dendrograms were drawn in excel.



Results and discussion

The results showed that by increasing salinity levels, tissue and uniformity of plants had inappropriate trend, but chitosan and biochar treatments caused improvement in the studied qualitative traits. The concentration of 0.2 g/L chitosan nanoparticle resulted in the lighter green, softer and more uniformity tissue than control sample. The mean comparison of simple effect of biochar on qualitative traits indicated the darker green, softer tissue and more monotony than control. by increasing level of chitosan nanoparticle, some morphological traits like wet and dry weight of plant increased significantly. The results of mean comparison of treatments showed that photosynthetic pigments decreased by various concentrations of salinity showing the most decrease by 125 mM salinity. However, 0.4 g/L chitosan nanoparticle caused the most Chl a, Chl b, total Chl, and carotenoid as 15%, 7.6%, 12%, and 14.2% compared to control, respectively. In addition, 4% soil weight of biochar resulted in the most Chl a, Chl b, total Chl, and carotenoid as 24.14%, 39.39%, 25%, and 14.29%, respectively.



Conclusion

It is concluded that 0.4 g/L chitosan nanoparticle and 4% biochar had the most effect on the studied traits in sport turfgrass such as morphological and physiological traits. In general, the studied treatments can be used in order to investigate morphological and biochemical traits in various species of turfgrasses.