Influence of Nano-silicon Treatment on Growth Behavior of ‘Sukkary’ and ‘Gahrawy’ Mango Root-stocks Under Salinity Stress

Abstract

The experiment was carried out in two consecutive seasons (2017/18 and 2018/19) on ‘Sukkary’ and ‘Gahrawy’ mango root-stocks seedlings and the purpose of the research was to investigate the effectiveness of applying Nano-silica to increase the tolerance of ‘Gahrawy’ and ‘Sukkary’ mango rootstocks. The tested treatments were tap water irrigation (TWI),TWI and spraying Nano silicon (SNSi) at 1.0g/L,Sea water irrigation (SWI) at 1750ppm, SWI at 1750ppm and SNSi, SWI at 3500ppm, and SWI at 3500ppm and SNSi. Foliar sprays of Nano-silicon were done four times;the first at the beginning of the experiment, and then three times at 45-days intervals.The effect of treatments on the behavior of the seedlings of the two rootstocks including vegetative characteristics (new leaf area, seedling height increase%, seedling stem diameter increase, root length and width, number of lateral and secondary roots and root growth coefficient), physiological parameter Leaf pigments, total phenols and soluble carbohydrates contents,leaf mineral contents N, P, K, Na, Ca and Mg and Non-enzymatic antioxidantsproline content and DPPH” as well as salinity symptoms parameters were studied. Increasing levels of salinity caused a decrease in most parameters and an increase in the sodium and proline content, and salinity symptoms of the leaves. Irrigation with salty water at 1750ppm together with foliar spraying Nano-silicon enhanced leaf content of pigments, soluble carbohydrate and total phenols, Mg, N, P, K and decreasing of salinity symptoms parameters.The results confirmed that the effects of Nano-silicon on the behavior of treated seedlings differ according to the variety under salinity conditions.