Photosynthesis and fructose 2,6-Bisphosphate content in water stressed wheat leaves

Abstract

The influence of low water potentials on net photosynthesis rates, sucrose levels, fructose 2,6-bisphosphate content and activities of fructose bisphosphatase and sucrose phosphate synthase was investigated in control and water stressed leaves of Trilicum aestivum L. var. sonalica. Fructose 2,6-bispho.sphate accumulated in water stressed plants and reduced leaf photosynthesis, sucrose content and activities of fructose bisphosphatase and sucrose phosphate synthase. 14C distribution into starch was more with increasing water stress, while its incorporation into sucrose was drastically reduced in stressed plants. Fructose- 6-phosphate-2-kinase activity was extremely high in stressed plants, while the activity of fructose 2,6bisphosphatase was low. The results clearly suggest that low leaf water potentials result in accumulation of fructose 2,6-bisphosphate which modulates photosynthetic sucrose tbrmation and carbon partitioning ill wheat leaves.