Abstract
1. The extraction of auxins from hypocotyls of tomato, noninoculated and inoculated with the gall-inciting schizomycete Phytomonas tumefaciens, has been studied. 2. Frozen vacuum-dried (lyophilized) tomato material does not yield auxins to dry ether. The immediately available or free auxin seems fixed until water liberates it. 3. Wet ether gave the best results as extractant, but even after seventeen successive extractions during 209 days, the process of auxin liberation had not reached completion. 4. Material boiled before extraction yields all its free auxin in one extraction by Soxhletization with wet ether for 24 hours, whereas non-boiled material continues to yield auxin. By combination of these methods the free auxin content may be distinguished from the potential or bound auxin. The latter may be a measure of auxin precursors, and is obtainable in part by digestion with chymotrypsin in the presence of toluene, from material freed from free auxin. 5. The inoculated hypocotyl yields both more free and more potential auxin than the noninoculated. 6. The significance of the finding that the growth disturbance known as crown gall is associated with disturbance in auxin relations (dysauxiny) is discussed with reference to the hypothesis that auxins play roles in normal and in healthy growth of plants and to the causal complex of gall development.