SILICON APPLICATION IMPROVES Fe AND Zn USE EFFICIENCY AND GROWTH OF MAIZE GENOTYPES UNDER SALINE CONDITIONS

摘要

Salinity causes decrease in maize growth and production. Maize occupies an important position in fodder and food crops of Pakistan. Recently, maize has been designated as silicon (Si) accumulator which can alleviate the salinity damage, a major constraint to agricultural crop production. With the objective to combat salinity stress in maize by Si applications using silicic acid Si(OH)(4), an experiments was conducted on two contrasting maize genotypes (salt sensitive; Pak-Afgoee and salt tolerant; Ev-5098), under normal and saline conditions. Three different levels of Si (0, 1 and 3 mM) were optimized for salinity tolerance on the basis of plant morphological characters especially dry weight in hydroponics. These Si-level was further used to investigate its effect on maize in hydroponic (0 mM NaCl) and saline (100 mM NaCl). The evaluation was done on the basis of various morphological, physiological, biochemical and growth traits during the experiments. Silicon supplementation into the solution culture significantly improved the K+: Na+ with reduced Na+ and increased K+ uptake. Plant water relations with higher water potential, increase in chlorophyll fractions and its ratios, enhanced stomatal conductance. It was concluded that Ev-5098 is better than Pak-Afgoee under salt stress and silicon inclusion into the any growth medium is beneficial for maize and can improve crop growth by maintaining plant water status, better K+: Na+ and recovering the plant defense system adversely influenced by salt stress.