The Physiology of Growth in the Wheat Plant

Abstract

The growth of the primary shoot of wheat and particularly of its inflorescence is described for plants grown in a controlled long-day environment. The technique of serial reconstruction is used to build up a comprehensive picture of volume growth for successive leaf primordia, the inflorescence, the spikelet, and the parts of the basal floret of a representative spikelet. This picture is linked with dry weight data for late developmental stages of all these structures. The whole is integrated in terms of relative rates of change of the parts. Length growth studies of the spike, the spikelet, and the floret parts reveal a number of correlative changes which would repay fuller investigation. Attention is drawn to the contrast between growth curves for stamens and for the carpel. That for the carpel is complex, and is most readily interpreted on the hypothesis that the gynaecium is composed of several foliar structures fused together. Volume growth for the stamens and carpels of the first five florets of a median spikelet is described in detail.