Influence of phosphorus nutrition on growth and metabolism of Duo grass (Duo festulolium).

Use of suitable plants that can extract and concentrate excess P from contaminated soil serves as an attractive method of phytoremediation. Plants vary in their potential to assimilate different organic and inorganic P-substrates. In this study, the response of Duo grass (Duo festulolium) to variable rates of soil-applied potassium dihydrogen phosphate (KH(2)PO(4)) on biomass yield and P uptake were studied. Duo grown for 5 weeks in soil with 2.5, 5 and 7.5 g KH(2)PO(4) kg(-1) soil showed a significantly higher biomass and shoot P content of 8.3, 11.4 and 12.3g P kg(-1) dry weight respectively compared to plants that received no soil added P. Also, the ability of Duo to metabolize different forms of P-substrates was determined by growing them in sterile Hoagland's agar media with different organic and inorganic P-substrates, viz. KH(2)PO(4), glucose-1-phosphate (G1P), inositiol hexaphosphate (IHP), adenosine triphosphate (ATP) and adenosine monophosphate (AMP) for 2 weeks. Plants on agar media with different P-substrates also showed enhanced biomass yield and shoot P relative to no P control and the P uptake was in the order of ATP>KH(2)PO(4)>G1P>IHP=AMP>no P control. The activities of both phytase (E.C.3.1.3.26) and acid phosphatases (E.C.3.1.3.2) were higher in all the P received plants than the control. Duo grass is capable of extracting P from the soil and also from the agar media and thus it can serve as possible candidate for phytoextraction of high P-soil.