Abstract

The Chinese happy tree, Camptotheca acuminata Decne, is grown extensively in plantations for harvest and extraction of its anti-cancer and potentially anti-viral compound, camptothecin. This study determined whether C. acuminata was amenable to clonal propagation as rooted cuttings and whether application of the rooting hormone, indole-3-butyric acid (IBA), affected chlorophyll fluorescence (F_V/F_M) or the percentage of cuttings that formed roots. The species was found highly amenable to vegetative propagation because a consistently high percentage of cuttings formed roots when treated with 3 or 8 g IBA / kg powder. IBA application was unnecessary in spring when more than 90% of untreated cuttings formed roots, but the highest IBA dose increased the number of plants produced by 18 and 82% (from tip cuttings) and by 46 and 102% (from node cuttings) in two later collections when rooting of untreated cuttings had declined. IBA treatments did not affect chlorophyll fluorescence. Industrial deployment of C. acuminata is entirely feasible using rooted cuttings, allowing clonal multiplication of genotypes that contain high levels of camptothecin.

Key words: Adventitious roots, auxin, Camptotheca acuminata, camptothecin, photoinhibition, propagation.