Relations Between the Dimensions of the Barley Root System: Effects of Mutilating the Root Axes

Abstract

A previous study indicated that intact cereal root systems develop in such a manner that relations between the total number, length, surface area, and volume of their members remain roughly constant during the vegetative growth period. To investigate this phenomenon further, barley plants were grown in water culture and were given one or other of the following treatments: root systems left intact, or root systems mutilated by removing the tip of each axis once it was 10-20 cm long. As expected, the intact and mutilated root systems developed markedly different patterns of branching. Surprisingly, however, the relations between root dimensions were almost identical in the two groups of plants. It is concluded that the extension and branching of cerea.l root systems are coordinated to an extent hitherto unappreciated. The implications of this discovery for the study of root systems are discussed.