Interaction effects of glucose and auxins in rooting etiolated stem segments of Salix tetrasperma

Abstract

Etiolated, 2·5 cm long stem segments of Salix tetrasperma did not root when cultured in agar even with 0·1% glucose, but rooted with 1·0% glucose in the medium. Rooting decreased with 2·0% and was completely inhibited by 5·0% glucose. Both IAA and IBA induced rooting when added to 0·1% glucose, the number of rooted segments decreasing with the concentration of IAA but increasing with that of IBA. Both auxins increased the number of roots when added to 1·0 and 2·0% glucose, the effect increasing with concentration except that 5·0 mg/1 IBA lowered the number as compared to 1·0 mg/1 added to 1·0% glucose. Auxins also induced rooting when added to 5·0% glucose, which alone inhibited it completely. The effect of auxins on the number of roots, however, decreased with the increasing concentration of glucose in the medium except with 5·0 mg/1 IAA which increased it. The results show that auxin effects on rooting are influenced by nutritional status of stem cuttings and that a proper balance of the two is necessary for this purpose.