Therefore, Fe-deficiency should be expected to facilitate
plants to acquire more N, P and K, three macronutrients which
are highly important in the improvement of crop yield and are thus
of the greatest concern of famers in agronomic management. From
this point of view, we assumed that mild Fe-deficiency induced an
increase in biomass production was probably due to the enhancement
of N, P and K acquisitions via the roots. However, this
assumption should not hold true for plants suffering from extreme
Fe-deficiency, because a certain Fe level in plants must be
maintained for normal growth. It is necessary to mention here that
the 50 lM FeEDTA treatment resulted in a low biomass of edible
parts when compared with the 10 lM FeEDTA treatment. This
result indicates that the 50 lM FeEDTA supply may exceed the
Fe requirement for the optimal growth of spinach plants