Metabolism of Labeled Exogenous Glucose in Fiber Flax Tissues

Abstract

Labeled glucose solution was introduced into cut fiber flax plants (45-50 cm high) under a pressure of 0.1 bar for 30 min, 1, and 2 h using a special device. The highest quantities of labeled carbon were revealed in the woody tissue. Sucrose made up a considerable proportion in low molecular weight products of [2-14 C]-glucose transformation (23.5%). Metabolism of labeled glucose in the leaves exposed to sunlight yielded a set of metabolites similar to products of 14 CO 2 photoassimilation. In the shade, the pattern of 14 C distribution in labeled compounds of the alcohol/water soluble fraction was similar to that in the light in mature leaves; while in juvenile leaves, 14 C content decreased in sucrose and increased in organic and amino acids. In the shade, the incorporation of 14 C into starch and hot water soluble polysaccharides increased at the expense of the acetone fraction (lipids and pigments), water/salt soluble proteins, and cellulose. Low light conditions increased the radioactivity ratio of sparingly soluble (KOH and Triton X-100 soluble) proteins to albumins and globulins. We propose that the synthesis of components of the photosynthetic apparatus in juvenile leaves is directly powered by photosynthesis and the photosynthesis of sucrose and the polymers compete for photosynthetic ATP. Appearance of sucrose in the xylem is due to its release from the phloem to the stem apoplast and the radial transfer to the xylem, where it is transported to the upper part of the shoot with the transpiration stream.

Guard‐cell apoplastic sucrose concentration – a link between leaf photosynthesis and stomatal aperture size in the apoplastic phloem loader Vicia faba L.

“…1997), the data are consistent, with the hexoses in the bulk‐leaf apoplast, particularly fructose, having a different origin (cf. Figs 3 & 4) such as the transpiration stream (Minchin & McNaughton 1987; Chikov & Bakirova 2004; Chikov et al. 2005), perhaps as a result of phloem leakage (e.g.…”

"Humanity Violates the Objective Laws of Nature Leading to an Ecological Catastrophe"

“…The carbon of glycolate metabolism products cannot return to the Calvin-Benson cycle and will replenish the pool of acids with subsequent effects on the invertase activity and the stomatal guard cells. In addition, the accumulation of hexoses in the cytoplasm and the non-return of inorganic phosphate to chloroplasts will enhance the synthesis of starch in chloroplasts [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30]. All this will increase photorespiration, which will protect the chloroplast photosynthetic apparatus from photo-destruction.…”

“…Under inhibition of assimilate export from the leaf (for example, as a result of a decrease in the number or activity of sink organs), it will be difficult to load sucrose into an overfull phloem. There will be an increase in its concentration in the apoplast, which will cause vacuolization of the phloem companion cells (as it is observed at an increase in the concentration of nitrates or NO, activation of the invertase by its substrate, increased sucrose hydrolysis and subsequent stomatal closure [31][32][33][34][35][36][37][38][39][40].…”