The Effect of Micro‐organisms on the Absorption of Manganese by Plants

Abstract

SUMMARYThe uptake of manganese by barley plants grown in solution culture is stimulated in the presence of micro-organisms, irrespective of whether they originated as casual laboratory contaminants or as rhizosphere micro-organisms in the soil. The microbial effect is mediated by a watersoluble substance but neither its identity nor its mode of action has yet been established.When manganese is supplied as EDTA chelates these appear to be broken down at or near the surface of the roots and this process is accelerated in the presence of micro-organisms. Under the conditions of these experiments EDTA was absorbed by the plants much less readily than manganese.

Iron Inefficiency in Maize Mutant ys1 (Zea mays L. cv Yellow-Stripe) Is Caused by a Defect in Uptake of Iron Phytosiderophores

“…Only the amount of extracellular Fe was greater in the roots of inoculated plants, indicating a microbial breakdown of Fe(II1)-EDTA (Barber and Lee, 1973) and accumulation of Fe in the root apoplasm. As expected, Fe-deficient Alice plants were very low in dry matter, showed severe symptoms of Fe deficiency, and contained higher concentrations of Mn and Zn in roots and shoots of both axenic and inoculated cultures.…”

Role of soil rhizobacteria in phytoremediation of heavy metal contaminated soils

“…Some rhizobateria can exude a class of rhizobateria secretion, such as antibiotics (including the antifungals), phosphate solubilization, hydrocyanic acid, indoleacetic acid (IAA), siderophores, 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase which increase bioavailability and facilitate root absorption of heavy metals, such as Fe (Crowley et al, 1991) and Mn (Barber and Lee, 1974), as well as nonessential metals, such as Cd (Salt et al, 1995), enhance tolerance of host plants by improving the P absorption (Davies et al, 2001;Liu et al, 2000) and promote plant growth (Budzikiewicz, 1997;Duffy and Défago, 1999;Burd et al, 2000;Ellis et al, 2000;Meyer, 2000). Abou-Shanab et al(2005) investigated the correlation between metal resistance and metal mobilization abilities of rhizobacteria under heavy metals stress.…”

Phytoextraction of Metals from Contaminated Soil: A Review of Plant/Soil/Metal Interaction and Assessment of Pertinent Agronomic Issues

“…In addition, some microorganisms may excrete organic compounds which increase bioavailability and facilitate root absorption of essential metals, such as Fe (Crowley et al, 1991) and Mn (Barber and Lee, 1974), as well as nonessential metals, such as Cd (Salt et al, 1995 , and Cd 2+ (Blake et al, 1993;Park et al, 1999). In addition, it has been estimated that microbial reduction of Hg 2+ generates a significant fraction of global atmospheric Hg 0 emissions (Keating et al, 1997).…”