The effect of soil volume availability on Opuntia ficus-indica canopy and root growth

The study investigated the effect of soil volume restriction on the below- and above-ground growth of Opuntia ficus-indica through understanding the limit imposed by root confinement via different soil volumes on root and canopy architecture and growth. In 2014, one-year-old O. ficus-indica cladodes were planted in five different soil volumes (50, 33, 18, 9 and 5 L). The cladode and roots of each sampled plants were measured and weighed every six months; a starch content estimation was performed using the perchloric acid method. The restricted soil volume had limiting effects on overall plant growth and influenced plant development. The largest canopy surface area and dry mass were measured in 50 L potted plants. Root system growth was inhibited by soil volume restriction: the total root length, surface area, dry mass and volume decreased due to this restriction. During the whole period, the starch content in cladodes and in roots grown on a 5 L soil volume was twice as much as in the largest, 50 L soil volume. Our results confirmed the importance of O. ficus-indica as a potential plant that can survive under low soil volume conditions. This plant has the ability to balance its growth and stay alive under harsh environments.