[Poly- and metaphosphates in higher plants (Lemnaceae)]

Area of Science:

• Plant Physiology
• Biochemistry
• Inorganic Chemistry

Context:

• Investigates phosphate metabolism in higher plants (Lemna perpusilla and Lemna gibba).
• Plants were pre-conditioned in a phosphate-free medium to study phosphate uptake and incorporation.
• Utilizes pulse-labeling with radioactive phosphate ([(32)P]orthophosphate) to trace metabolic pathways.

Purpose:

• To identify and characterize condensed inorganic phosphates formed in plants after phosphate labeling.
• To determine the distribution of radioactivity within different classes of condensed phosphates.
• To explore the potential role of condensed phosphates in cellular energy regulation.

Summary:

• Radioactive phosphate was incorporated into various condensed inorganic phosphates, including linear oligophosphates (2-7 residues) and cyclic tri-, tetra-, penta-, and hexametaphosphates.
• Isolation and characterization were performed using joint extraction with nucleic acids and fractionation on methylated serum albumin and Kieselgur (MAK).
• Two-dimensional thin-layer chromatography revealed the presence and relative abundance of these compounds.
• Trimetaphosphate exhibited significantly higher radioactivity compared to other low-molecular condensed inorganic phosphates.

Impact:

• Provides insights into the metabolic fate of inorganic phosphate in plants.
• Suggests a regulatory role for condensed phosphates, particularly trimetaphosphate, in the ATP-ADP-Pi system.
• Contributes to understanding plant phosphorus nutrition and energy metabolism.