Condensed tannins in the tissue culture of sainfoin (Onobrychis viciifolia Scop.) and birdsfoot trefoil (Lotus corniculatus L.)

Abstract

Two forage legumes, birdsfoot trefoil (Lotus corniculatus L.) and sainfoin (Onobrychis viciifolia Scop.), containing condensed tannins in their leaves and stems were used as source material to study condensed tannins in tissue culture. More protoplasts were isolated from mesophyll tissue of a low tannin-containing strain of birdsfoot trefoil than from a high tannin-containing strain, but more tannin-filled protoplasts were observed in the latter. Growth rates of leaf explant-derived callus tissue were greater for the high-tannin than for the low-tannin strain. In sainfoin, callus cultures from leaf explants produced numerous tannin-filled cells by 21 days. Explants from sainfoin cotyledons and roots, tissues which normally do not contain tannins, also formed callus with tannin-filled cells in 21 days but in almost every case, a cytokinin was required for tannin formation to occur. The occurrence of tannin-filled cells in callus from root and cotyledon explants was variable and genotype specific. These results show that endogenous tannins can affect protoplast isolation and possibly callus growth in birds-foot trefoil, and that the formation of condensed tannins in sainfoin callus culture can be influenced by a growth regulator.