Effects of foliar application of nanoparticles (zinc and silicon) and putrescine on chlorophyll fluorescence indices, dry matter remobilization and the contribution of this process in grain yield of wheat under salinity stress

In order to study the effects of foliar application of nanoparticles (zinc and silicon) and putrescine on chlorophyll fluorescence indices, dry matter remobilization and the contribution of this process in grain yield of wheat under salinity stress, an experimental as factorial based on a randomized complete block design with three replications will be conducted in the research greenhouse of the Faculty of Agriculture and Natural Resources, University of Mohaghegh Ardabili in 2021. Factors experimentally included salinity at four levels (no salinity as control, salinity 40, 80 and 120 mM by NaCl), and foliar application of nanoparticles (Zn and Si) and putrescine at eight levels (foliar application with water as control, foliar application 50 mg.L-1 nano silicon, foliar application, 1 g.L-1 nano znic oxide, foliar application of putrescine, foliar application of nano Si-Zn oxide, foliar application of nano silicon and putrescine, foliar application of nano Zn oxide and putrescine, foliar application of nano Si-Zn oxide and putrescine). The results showed that foliar application of nanoparticles (Zn and Si) and putrescine under no salinity increased variable fluorescence (95.8%), maximum fluorescence (35.33%), quantum yield (42.24%), leaf area index (45.27%), flag leaf protein  (41.8%), total dry matter (44.09%), current photosynthesis (87.15%) and the contribution of current photosynthesis in grain yield (36.04%) and grain yield (37.34 %) compared to no foliar application of nanoparticles and putrescine under the highest salinity level. But the maximum dry matter remobilization from stem and shoot (37.8 and 38.15%, respectively) and the contribution of these processes to grain yield (89.45 and 90.22%, respectively) were obtained in no foliar application of nanoparticles and the putrescine under salinity 120 mM. It seems that nanoparticles and putrescine application can increase grain yield of wheat under salinity stress due to improving current photosynthesis and chlorophyll fluorescence indices.