Here, we investigate the hypotheses that stem bending can be
due to adverse water relations and lack of mechanical support of
the stem. The role of water relations was tested by determining
water loss from the floral head and stem segments, and by covering
the stem with a flexible plastic bag. The possible role of mechanical
support was tested by studying the extension of stem sclerenchyma
and lignin formation, stem lignin levels, the shape of the cavity in
the stems, and stem elongation.