Ciclo di accrescimento e differenziazione delle gemme in piante perenni nel territorio di Bari

Summary

Growth Cycle and Buds Differentiation in Perennial Plants Growing in Bari's area. - III. The evolution of the wood ring in Prunus Amygdalus Stokes, From December 1946 to December 1947.

1. The cambial tissue starts dividing during the month of March in the stem, and stops its activity in the month of November.

2. The initiation of cambial activity and the unfolding of leaf buds fall in the same time.

3. From March to May the cambium differentiates the early wood (one series of wood vessels). This part of the wood ring does'nt seem to have a great climatic value.

4. From May to October intermediate and end wood is settled. This part of the wood ring has the greatest climatic meaning. Its thikness depends upon its development, and its development depends, on the other side, upon climatic factors.

   In this part of the wood ring false rings may occur, dependent upon climatic variations.

5. In the branches bearing flower buds the cambium starts dividing in November-December, probably in relation with pollen formation in the buds.

   After a period of winter resting, the wood ring completes its formation in the successive Spring-Summer time, scarsely preceeding the cambium activity of the stem.

6. The young branches in which leaf buds prevail, shaw a cycle of the cambial activity, like that of the stem, preceeding it of some while. This behaviour shows that the stimulus to division of the cambial cells is of chemical nature, and that it is elaborated in the young branches (probably in the vegetative buds).