Effect of foliar and soil application of zinc on photosynthetic pigments, chlorophyll fluorescence and grain yield of wheat under soil salinity

Soil salinity is one of the most serious limiting factors for crop growth and production in the arid and semi-arid regions. Zinc is an essential micronutrient for humans, animals and plants, which act either as the metal component of enzymes or as a regulatory co-factor of a large number of enzymes. Zinc is required for chlorophyll synthesis and plays an important role in biomass production. Zinc is required for pollen function, fertilization and germination plays an important role. Zinc deficiency is recognized as a critical problem in plants, especially grown on saline conditions with high pH values. But, recent researches have shown that a small amount of nutrients, particularly Zn applied by foliar spraying can affect ability of plants to salinity stress. So, the aim of this study was to investigate the effects of foliar and soil application of zinc on photosynthetic pigments, chlorophyll fluorescence and grain yield of wheat under soil salinity

A factorial experiment was conducted based on randomized complete block design with three replications in research greenhouse of faculty of agricultural and natural resources, University of Mohaghegh Ardabili in 2018. Factors experiment were included soil salinity in four levels (non-salinity, salinity 30, 60 and 90 mM by NaCl), foliar and soil application of zinc in four levels (without zinc as control, soil application of ZnSo4, foliar application of nano zn oxide, both application of ZnSo4 and nano zn oxide).

The results showed that both application ZnSo4 and nano zn oxide under non-salinity condition, increased chlorophyll a, b, total chlorophyll, cartenoeid and grain yield (65.2, 52.72, 62, 50.43 and 34.56 % respectively) in comparison with no application of zinc under salinity of 90 mM. Also, both application of ZnSo4 and nano Zn oxide under without salinity, increased maximum fluorescence (Fm) and variable fluorescence (Fv). Grain yield decreased 34.56% under salinity of 90 mM and without application of zinc in comparison with both application ZnSo4 and nano zn oxide under non-salinity condition due to increasing minimum fluorescence (F0) and decreasing chlorophyll content.

It seems that both application of ZnSo4 and nano zn oxide can increase grain yield of wheat under salinity stress due to improving Potosynthetic pigments and chlorophyll fluorescence components.

The results showed that both application ZnSo4 and nano zn oxide under non-salinity condition, increased chlorophyll a, b, total chlorophyll, cartenoeid and grain yield (65.2, 52.72, 62, 50.43 and 34.56 % respectively) in comparison with no application of zinc under salinity of 90 mM. Also, both application of ZnSo4 and nano Zn oxide under without salinity, increased maximum fluorescence (Fm) and variable fluorescence (Fv). Grain yield decreased 34.56% under salinity of 90 mM and without application of zinc in comparison with both application ZnSo4 and nano zn oxide under non-salinity condition due to increasing minimum fluorescence (F0) and decreasing chlorophyll content.

It seems that both application of ZnSo4 and nano zn oxide can increase grain yield of wheat under salinity stress due to improving Potosynthetic pigments and chlorophyll fluorescence components.