Assimilation of Phytate-phosphorus by the Extracellular Phytase Activity of Tobacco (Nicotiana tabacum) is Affected by the Availability of Soluble Phytate

By Shiu-Cheung Lung, B. Lim. Plant and Soil, 2005

94 citations recorded by the source corpus.

Phytate, the major organic phosphorus in soil, is not readily available to plants as a source of phosphorus (P). It is either complexed with cations or adsorbed to various soil components. The present study was carried out to investigate the extracellular phytase activities of tobacco (Nicotiana tabacum variety GeXin No.1) and its ability to assimilate external phytate-P. Whereas phytase activities in roots, shoots and growth media of Pi-fed 14-day-old seedlings were only 1.3–4.9% of total acid phosphatase (APase) activities, P starvation triggered an increase in phytase secretion up to 914.9 mU mg−1 protein, equivalent to 18.2% of total APase activities. Much of the extracellular phytase activities were found to be root-associated than root-released. The plants were not able to utilize phytate adsorbed to sand, except when insoluble phytate salts were preformed with Mg2+ and Ca2+ ions for supplementation. Tobacco grew better in sand supplemented with Mg-phytate salts (31.9 mg dry weight plant−1; 0.68% w/w P concentration) than that with Ca-phytate salts (9.5 mg plant−1; 0.42%), presumably due to its higher solubility. We conclude that insolubility of soil phytate is the major constrain for its assimilation. Improving solubility of soil phytate, for example, by enhancement of citrate secretion, may be a feasible approach to improve soil phytate assimilation.

Subfields: Plant Science

View Paper: https://www.semanticscholar.org/paper/2b58bbc793727421c4d828178193a607f378d9cf

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Plant Science

Citations in the corpus

Microbial phytase activity and their role in organic P mineralization (2015, background): “Phytases are capable of hydrolyzing the soluble forms of Ca2+ and Mg2+ inositol phosphates, but were incapable in the case of Al3+, Fe3+, Cu2+ and Zn2+ inositol phosphates adsorbed to sand (Lung & Lim 2006; Tang et al. 2006; El-Toukhy et al. 2013).”
Organic-acid-producing, phytate-mineralizing rhizobacteria and their effect on growth of pigeon pea (Cajanus cajan) (2010, background): “It has been shown that in case of phytase-exuding transgenic plants, the assimilation of phytate P is limited by the availability of phytate in the soluble phase (George et al., 2005; Lung and Lim, 2005).”
Phosphatase and phytase activities in nodules of common bean genotypes at different levels of phosphorus supply (2008, background): “Plant phytases yet purified and characterised are indeed acid phosphatases that possess high specific activities against inositol hexaphosphate (Lung and Lim 2006).”
Plant and microbial strategies to improve the phosphorus efficiency of agriculture (2011, background): “In contrast, limited success has been observed when the plants have been evaluated in soil or in growth conditions where the availability of substrate was restricted, irrespective of total P content (George et al. 2005a, b; Lung and Lim 2006).”