Distribution of starch and lipids in reaction wood of some angiosperm trees

Distribution of starch and lipids has been studied in upper and lower parts of tilt branches and vertical branches of Azadirachta indica A. Juss., Mangifera indica L. and Polyalthia longifolia (Sonn.) Thw. Starch grains in tiltwood are smaller than in vertical wood. Their accumulation is considerably lower in upper tiltwood than in lower tiltwood and vertical wood. The rays and axial parenchyma contiguous to vessels show the highest lipid content in the upper tiltwood of A. indica and P. longifolia. The accumulation of lipids in axial and ray parenchyma of upper tiltwood is smaller than in lower tiltwood and vertical wood. Since we found that not only the upper wood but also the lower part of the tilt wood is different from normal wood, we would like to suggest that the entire new wood of a leaning stem should be considered to be reaction wood.