Copper Hydroxide Improved Root Quality of Palimara Alstonia in Plastic Containers

Abstract

The effect of copper hydroxide [Cu(OH)2] applied to interior container surfaces on shoot and root responses was evaluated on palimara alstonia (Alstonia scholaris). The seedlings grown in Cu(OH)2-treated containers had greater plant height than those in untreated containers, and had no observable copper toxicity symptoms. Cu(OH)2-treated containers effectively reduced root circling on the surface of rootballs compared with untreated containers. The Cu(OH)2 treatment significantly increased the dry weight of fine roots (those with a diameter 0-2 mm) and small roots (>2-5 mm) but did not influence the dry weight of medium roots (>5-10 mm), large roots (>10 mm), or total roots. The Cu(OH)2 treatment also significantly increased total root length and surface, which was due principally to the increasing length and surface of the fine roots. The results indicated that the Cu(OH)2 treatment, which can improve the root quality of palimara alstonia seedlings and thereby increase the root-length-to-leaf-area ratio and the root-surface-to-leaf-area ratio, has the potential to produce high-quality plants.