Abstract
We previously revealed that in Fe deficient barley, the expression of genes involved in assimilation of N and S was decreased in younger chlorotic leaves, and senescence was accelerated in older leaves. Based on these observations, we hypothesize that the acceleration of senescence in older leaves is involved in the adaptive mechanism to Fe deficiency, which compensate for decreased assimilation of N and S in younger chlorotic leaves by remobilization of assimilated products. To assess the possibility of this hypothesis, we cultured barley and rice under Fe deficient condition and determined elements concentrations in each part of plants during 24 days.
In older leaves of both plants, Zn and Mn concentrations were increased by Fe deficiency. N concentration in all leaves of Fe deficient barley decreased, and it decreased earlier and to greater extent in older leaves. However, N concentration in rice leaves was not changed by Fe deficiency. These results support the possibility that in Fe deficient barley, accelerated senescence in older leaves compensate for decreased N assimilation in younger chlorotic leaves by remobilizing assimilated N from older leaves.
