Lignosulfonates: Novel promoting additives for plant tissue cultures

Lignosulfonates (LIGNs) are low-cost by-products from the paper industry an d are already commercialized as fertilizers. Because earlier laboratory and glasshouse assays had shown a beneficial effect of LIGNs on rooting and ge neral plant vigor, their incorporation in several plant tissue culture type s was examined here. The present assays indicated that well-chosen concentr ations of LIGNs, whether they were chelated with Ca or Fe, stimulated growt h of a normal and an habituated sugarbeet callus, improved multiplication r ate and vigor of a shoot-proliferating poplar cluster, and increased the ro oting percentage of hell!: ginseng, and poplar shoots. Complementing the ex ogenous rooting auxin with LIGNs enhanced the increases of endogenous level s of indoleacetic acid and its aspartate conjugate in the basal parts of po plar shoots at the rooting inductive phase. Although LIGNs exerted some eff ects in the absence of the growth regulators, they could not replace them. Their possible mode of action is discussed.