CERTAIN STRUCTURAL RESPONSES OF TWO MAIZE CVS. DIFFERing IN THEIR SALT TOLERANCE TO TRACE· ELEMENTS UNDER SALINE CONDITIONS

The effects of both salinity at 2.5 dsrn and foliar application with some
trace-elements. i.e., Zn, Fe and Mn each alone or in combination on growth and
anatomical structure of both roots and leaves of two maize cultivars differing in their
salt tolerance were investigated. The role of the trace-elements on recovery the
adverse effects of salinity was also studied.
Salinity at 2.5 dsrn' significantly decreased plant height, leaf area
(cm²Iplant). number and length of adventitious roots during the two growing seasons.
The effects of salinity was more pronounced in salt sensitive cultivar, (two 310) than
the other one. Under both salinized and non-sallnized conditions. treatments with
micronutrients each alone or in combinations not only increased all the above
mentioned growth parameters compared with control, but also counteracted the
harmful effects of salinity. Treatments with zinc alone or in combination were the
most effective in this respect.
Anatomically, salinity decreased root diameter, exodermis thickness, cortex
thickness, endodermal layer thickness and vascular cylinder diameter. In addition.
salinity decreased thickness of the leaf in keel region, upper and lower epidermis and
mesophyll tissue as well as large vascular bundle dimensions due to its effects on
decreasing thickness of xylem and phloem tissues. Me~axylem vessel diameters were
also decreased. Trace-element treatments each alone or in combinations increased
all the above mentioned anatomical pararnete-s. Treatment with zinc alone or in
combination proved to be more effective in t~· s respect.
It seems that. develcornent .;( an extensive root system, formation of
aerenchyma in the cortex tissue, early formation of exodermis play an important role
not only in the adaptive mechanism to salinity but also in improvement plant tolerance
to salinity.