Effects of nanosilicon dioxide on leaf anatomy, chlorophyll fluorescence, and mineral element composition of strawberry under salinity stress

Abstract

Leaf morphology and anatomy are important criteria to evaluate plant tolerance to salinity stress. Therefore, in this study the morphophysiological responses of strawberry (Fragaria’× anansa Duchesne “Camarosa”) plants treated with nanosilicon (nSiO2) were investigated under salt-stress conditions. The plants in a complete nutrient solution designed for strawberry were exposed to salt stress (0, 25, or 50 mM NaCl) and treated with nanosilicon before (0, 50, or 100 mg L−1) or after (0 or 50 mg L−1) floweringConcentrations of sodium (Na), chlorine (Cl), and calcium (Ca) increased in plants exposed to salt stress, whereas silicon (Si), potassium (K), and phosphorus (P) decreased. In the presence of nanosilicon, strawberry plants absorbed K, P, and Ca from the nutrient solution and transferred the nutrients to leaves effectively. Only a little amount of Ca, Cl, or Na was transferred to leaves with presence of nanosilicon. The adverse effects of salinity on phyllochron, flowering, and fruit set, and fruit production parameters were suppressed by application of nanosilicon. Analysis by optical microscopy revealed that salt stress limited the number of parenchyma cells, leaf thickness, epidermis cell thickness, and mesophyll thickness, thereby leading to restrictions in chlorophyll content and photosynthetic efficiency. Nanosilicon application reduced negative effects of salinity by improving cell wall thickness, providing higher content of water, and leading to increased chlorophyll content and fluorescence. Overall, these observations indicated that application of nanosilicon can suppress the adverse effect of salinity on anatomical and physiological changes of strawberry plants.