Pineapple Chlorosis in Relation to Iron and Nitrogen

Publisher Website
Google Scholar
Abstract
Pine-apple plants grown in solution cultures with ample and partially deficient Fe contained more chlorophyll and produced greater plant and fruit weight in the cultures with ample Fe. Fe requirements for chlorophyll synthesis were very low. Fe intake and translocation was reduced by phosphate through precipitation. Chlorosis symptoms did not differ between N-deficient and Fe-deficient plants. During N deficiency, leaves formed before and during the period of deficiency become chlorotic in variable degrees, the former by chloroplast breakdown in a medium lacking new N supplies for the regeneration of chloroplastic proteins. In Fe deficiency, only leaves formed during the deficiency period become chlorotic, while those formed previous to this period remain relatively green. Chlorosis in Fe-deficient plants develops when there is an inverse relationship between rates of Fe intake and plant growth. Fe accumulations, resulting long after the tissues have undergone functional differentiation, were not closely related to chlorophyll concentrations. Chlorosis, though qualitatively similar, was more extensive and rapid in plants with N than with Fe deficiency. Chlorophyll, carotenoids and protein increased simultaneously in the green leaves of plants with Fe sufficiency but decreased in the chlorotic leaves with Fe deficiency. Sugar concentrations in the proximal regions of leaves with meristematic tissues were greater in chlorotic than in green leaves because of low sugar utilization at low growth rates. Plant or fruit growth rates were not related to total sugar or starch concentrations. Nitrate intake and assimilation were greater in green than in chlorotic plants and were responsible for the greater amounts of total organic -N and protein in the former.

This publication has 20 references indexed in Scilit: