![Sample our Environment & Sustainability journals, sign in here to start your access, latest two full volumes FREE to you for 14 days]({"type":"image" , "src" : "/sda/5935/TOC-Subject-Sample-2021-Environment-Sustainability.jpg"})
Abstract
Ferrous iron (Iron2+ and Fe2+) has been considered by many investigators to be the active form of iron (Fe) in plants. Experiments were conducted to determine differences in Fe2+ and total Fe in newly emerging leaves of sorghum [Sorghum bicolor (L.) Moench] and maize (Zea mays L.) genotypes considered to be “Fe‐susceptible”; and “Fe‐tolerant”; to low levels of Fe. Treatments consisted of growing plants in nutrient solutions with Fe (+Fe) and without Fe (‐Fe) under growth chamber conditions. Once Fe deficiency chlorosis symptoms were visually observed in plants grown with ‐Fe, leaf samples were collected daily from plants grown in both ‐Fe and +Fe solutions for Fe2+ and total Fe determinations.
Iron2+ in the newly emerging leaves of plants grown in ‐Fe or +Fe solutions remained fairly constant. Total Fe changed daily and was dependent on the amount of Fe deficiency stress in sorghum, but not necessarily in maize. Total Fe and Fe2+ values were fairly similar in plants with severe Fe deficiency chlorosis symptoms. Sorghum and maize plants regreened after Fe had been added to the growth solutions and total Fe increased within the developing leaves of these plants within two to three days. Total Fe increases appeared to be rhythmic in sorghum. Total Fe changes were related to the degree of Fe deficiency stress, but Fe2+ was not2+. The active Fe in the leaves of these plants was not related to Fe2+ , but to total Fe (or Fe3+ if total Fe minus Fe2+ is equivalent to Fe3+ ). The daily fluctuations of total Fe may help explain why Fe deficient leaves often contain more Fe than green leaves.