Partitioning of Dry Matter and the Deposition and Use of Stem Reserves in a Semi-dwarf Wheat Crop

An experiment was carried out within a crop of spring wheat(cv. Condor) to examine dry matter partitioning between thedeveloping stem and ear, and to estimate the magnitude of carbonstored in the stem both before and after anthesis, and the subsequentutilization of these reserves during grain growth. The amount of reserve laid down and mobilized was estimatedfrom analysis of data for changes in masses of stem and leaffrom frequent harvests. The rate of change of the dry mass ofthe individual plant organs was expressed as a proportion ofthe rate of change of the total dry mass of the large culm.This value was called the Allocation Ratio (AR). It was assumedthat assimilate was transferred directly from the stem intothe growing ear, and not into other organs. This paper providesevidence for the idea that the stem intemodes of wheat are ableto accumulate and subsequently mobilize a dry matter reserve.The accumulation and subsequent mobilization of fructans inthe stem was demonstrated using ascending thinlayer chromatography.On a dry matter basis the large culms of the wheat crop accumulatedall of their stem reserves after anthesis (0–41 g perlarge culm; 98·4 g m^–1). After adjusting the lossof mass by 33% to allow for respiration, it was concluded thatpost-anthesis stem reserves may have contributed at least 21%of the final grain yield of this crop. Triticum aestivum L., semi-dwarf spring wheat, dry matter partitioning, stem reserves, fructans