Studies on the Chemistry of the Living Bark of the Black Locust Tree in Relation to Frost Hardiness. IV. Effects of Ringing on Translocation, Protein Synthesis and the Development of Hardiness

Abstract

Analyses and hardiness tests conducted on living tissue of segments of bark, isolated on locust trees at various times during the summer by ringing, indicate such a high degree of parallelism to exist between the water soluble protein content (in excess of a summer min.) and the state of hardiness of these tissues that a causal relationship can be inferred. This finding is confirmatory to that previously indicated in seasonal studies on normal trees. Synthesis of water soluble protein, the accumulation of which in the tissues parallels development of hardiness, is dependent upon the accumulation of some factor(s) which must reach the bark cells through phloem transport prior to their isolation, by ringing, from the leaves (or roots) of the tree. This factor appears to be mobilized from the leaves only in late summer and fall, reaching maximal transport in Sept. just prior to leaf abscission. A relationship between the accumulation of this soluble protein, hardiness development, and the so-called autumnal migration of nitrogenous substances from the leaves to the bark tissue is obvious. No such relationship has been detected in normal trees or in trees under abnormal conditions between the state of hardiness of bark tissue and its content of insoluble protein, non-protein nitrogen or carbohydrates.