Evidence for the existence of functional roots on potato tubers and stolons: Significance in water transport to the tuber

Abstract

Field observations of potato plants showed various types of roots. There were roots originating at the base of the main stem (basal roots); roots arising from the mainstem at the junction of the stolon to the mainstem (junction roots); roots on the stolons (stolon roots) and roots growing directly from the base of the buds on the tuber (tuber roots). The path of water uptake and movement was studied by examining the transport of a water soluble dye from each type of roots. The results showed xylem connections from the different types of roots to the tuber as well as to the aerial part of the plant. However, under field conditions the basal and the junction roots do not appear to transport water to the tuber. The stolon and the tuber roots, on the other hand, transported water to the tuber under similar moisture conditions. To our knowledge this is the first report documenting the presence of potato tuber roots. Our study clearly demonstrates the role of tuber and stolon roots in tuber water uptake. These roots may play a role in tuber calcium uptake which is thought to move primarily with the water in the xylem.