Changes in carbohydrate metabolism in the wheat root tip after growth and vernalization

Abstract

The serial section technique was used to delimit 0.5-mm regions of the root tip. Seven such sections numbered from the root tip backwards were examined to a total length of 3.5 mm.Developmental changes in the root tip cells of Marquis (spring) and Rideau (winter) wheats were closely correlated with sequential changes in the content of free sugars (sucrose, glucose, fructose, raffinose, and galactose), starch, and amylase. Specific varietal differences were observed both before and after vernalization.Spatially comparable root tip sections derived from previously vernalized grains revealed marked changes in the content of the sugars and starch. A shift in the starch–sugar equilibrium is noted with cellular development. For the most part, in Rideau wheat, the amount of these metabolites in any specific section derived from a vernalized root tip was more nearly comparable to the chronologically less mature tissue of the control roots, i.e. section 3 of the vernalized root compared more closely with section 2 of control roots.Amylase activity increased markedly after vernalization in the winter wheat but did not change in the spring wheat. Its activity could be directly correlated with changes in the amount of sucrose (not starch). Starch content increased in the more mature root tip cells of both varieties after vernalization.Sugar, amylase, and starch content were primarily a function of the developmental stage of the root tip cells, vernalization effected secondary smaller changes.

Regulatory Networks of Flowering Genes in Angelica sinensis during Vernalization

“…For vernalization to occur, sources of energy (sugars) and carbohydrate metabolism are required [ 33 , 68 ]. Twelve genes were found to be involved in sucrose metabolism: trehalose-phosphate synthases (TPS1, TPS5, TPS7 and TPS10), which are required for vegetative growth and transition to flowering by regulating starch and sucrose degradation [ 69 , 70 , 71 ]; sucrose synthases (SUS2 and SUS3), which provide UDP glucose and fructose for various metabolic pathways [ 72 ]; sucrose-phosphate synthases (SPS and SPS1), which regulate sucrose synthesis from UDP glucose and fructose-6-phosphate [ 73 ]; phosphoglucomutases (PGMP and PGM1), which participate in both the breakdown and the synthesis of glucose [ 74 ]; and beta-amylases (BAM1 and BAM3), which play roles in circadian-regulated starch degradation and maltose metabolism [ 75 ].…”