The Damage of Root, Leaf and Chloroplast Ultrastructure on Maize Seedlings Caused by Salinity Stress

Abstract

Salinity is one of major problems in agriculture especially in arid and semiarid area that causes the damage of many aspects in plant growth and development. This study observed root, leaf and chloroplast ultrastructure as well as nutrient uptake in maize plants exposed to salinity stress. Maize seedlings were treated with 0, 1, 2 and 3% NaCl for 5 days and placed in the growth chamber. Root, leaf, and chloroplast ultrastructure were observed by using SEM and TEM. Nutrient uptake was estimated from the content of trace elements of leaves that quantified by using ICP-MS, except chlorine by an atomic absorption flame spectrometer. The results showed that salinity slightly damaged roots anatomy. Epidermis and parenchyma cells of cortex and pith were shrinkage in 2 and 3% NaCl-treated plants. Leaf anatomy observation showed mesophyll and bundle sheath cells slightly suppressed. Chloroplasts content inside those cells were dramatically decreased. Ultrastructure observation showed the damage of chloroplasts inside mesophyll cells. Anatomical and ultrastructural damage of roots, leaves, and chloroplasts was accompanied by altering uptake of some trace elements. The contents of aluminum, calcium, iron, magnesium, sodium, chlorine, in NaCl-treated plants, were higher than control. Otherwise, boron, potassium, and phosphor were lower.