Recently Schunmann et al, (1997; Plant, Cell and Environment 20, 1439-1450)
investigated the correlation of spatial patterns of xyloglucan-endotransgl
ycosylase (XET) activity, XET-related mRNAs, and growth in elongating barle
y (Hordeum vulgare L.) leaves. Here, methodological difficulties in the kin
ematic growth analysis are discussed, and it is concluded that the role tha
t XET-related gene activity plays in the control of spatial growth patterns
remains undetermined.