Mechanical differences between free-standing and supported wheat plants, Triticum aestivum L.

Abstract

The effect of wind sway on the mechanical characteristics of the anchorage roots and the stem was investigated in mature winter wheat (Triticum aestivum L., cv. Hereward). Wheat plants were field-grown, either supported by a frame, which prevented wind sway, or unsupported (free-standing) and the morphology and mechanical properties of the stems and the anchorage, 'coronal', roots were measured. Wind sway had little influence on either the stem height or ear weight of the plants but did affect the mechanical properties of the stem. Stems of supported plants were weaker and more flexible than the stems of free-standing plants. There were also differences in the anchorage systems between the treatments: supported plants had just under half as many 'coronal ' anchorage roots as the free-standing plants. This reduced the anchorage strength of supported plants by a third. These differences in mechanical structure meant that the free-standing plants were more resistant to stem buckling and more resistant to anchorage failure. However, considering the difference in the need for mechanical strength in plants from the two regimes, these differences were small. This suggests that wheat has inherent mechanical integrity and, as a monocotyledon with no secondary thickening, it differs little structurally between environments. © 1996 Annals of Botany Company.