Glutathione foliar fertilisation prevents lime‐induced iron chlorosis in soil grown Medicago scutellata

Abstract

It has been proposed that glutathione can relieve the effects of Fe deficiency. This study tested the effects of glutathione foliar treatments to prevent Fe chlorosis, using as positive controls soil and foliar Fe fertilisation. Medicago scutellata plants were grown in soil (5.7% CaCO3) supplemented or not with 4 and 8% CaCO3. Two Fe(III)‐EDDHA soil treatments (5 and 10 mg Fe kg−1), and three foliar treatments (three applications each of 2.14 mM Fe(III)‐EDDHA, 1 mM glutathione, and the previous two combined) were applied. Measurements include leaf chlorophyll and Fe concentrations, biomass, leaf enzymatic and non‐enzymatic antioxidant systems and carboxylates. The addition of CaCO3 caused typical Fe deficiency symptoms, including changes in chlorophyll, Fe, antioxidant systems and carboxylates, which were prevented by soil and foliar Fe fertilisation. The foliar treatment with glutathione also led to higher chlorophyll, leaf extractable Fe and root Fe, as well as decreases in some antioxidant systems, whereas leaf Fe concentrations decreased. The combined foliar application of glutathione and Fe was even more efficient in preventing chlorosis. Including glutathione in foliar fertilisation programs should be considered as an option for Fe chlorosis prevention, especially when relatively large leaf total Fe concentrations occur in the so called chlorosis paradox.

Foliar applications of thidiazuron and putrescine increase leaf iron and chlorophyll concentrations in iron-deficient pot marigold (Calendula officinalis L.)

“…Results shown here confirm add TDZ to the list of compounds that can be used to improve Fe mobilization within the plant. This was already known to occur with phenolic compounds (Jin et al 2007), PUT (Zhu et al 2016), and glutathione (Gheshlaghi et al 2019), whereas the opposite effect was found with nitrosoglutathione (Ye et al 2015). Until now, CK has been generally considered to be a negative regulator of Fe-deficiency responses, with the production of NO having the opposite effect (Hindt and Guerinot 2012).…”

Two Fe mining sub-products and three thiol compounds alleviate Fe deficiency in soybean (Glycine max L.) grown in a calcareous soil in greenhouse conditions

“…For mineral analysis, tissues from three plants in a given treatment (two in the case of roots) in each pot were pooled. Nitric-perchloric acid digestion was carried out with standard procedures (AOAC 2000) as described in Gheshlaghi et al (2019). The concentrations of Fe in the nal solutions were determined by ICP-OES (Spectro Arcos, Spectro Analytical Instruments, Kleve, Germany), calibrating the device daily with certi ed standards and including standard solutions and blanks in each sample set.…”

“…Ascorbate peroxidase (APX; EC 1.11.1.11) and GR (EC 1.6.4.2) activities were measured in leaf extracts as in Nakano and Asada (1981) and Carlberg and Mannervik (1985), respectively. All these methods were described in detail in Gheshlaghi et al (2019).…”

“…Determination of ascorbate, gibberellic acid and abscisic acid in leaves Ascorbate (Asc) was determined with α,α-dipyridyl (Masato 1980), as described in Gheshlaghi et al (2019). Extraction and determination of gibberellic acid (GA3; thereafter called GA) was carried out according to Berríos et al (2004) with some modi cations.…”

“…It has been recently shown that when GSH was supplied to the roots of Medicago scutellata growing in a Fe-rich rock sand, GSH was capable of mobilize Fe from the substrate, increasing plant Fe concentrations and relieving Fe-de ciency symptoms (Gheshlaghi et al 2020). Also, supplying GSH to the foliage of M. scutellata increased internal Fe availability and relieved Fe-de ciency symptoms (Gheshlaghi et al 2019). The application of GSH to the soil to control Fe de ciency in plants has not been tested yet.…”