Dynamics of seasonal changes of starch content, in the shoots and leaves of lilac

Changes of starch content in the bark and wood of shoots of the current year, 1-4-year-old shoots and in the leaves of lilac were determined. The presence of starch in the bark and in the wood during the whole pear, and in leaves during the whole vegetation period was demonstrated. The bark contains from twice to four times as much starch as the wood. The dynamics of changes in the starch content is similar in all examined year groups of shoots and in leaves. In winter the content of starch in the shoots decreases, with the smallest amounts occurring in spring (about 1% in May). In the following period the content of starch increases; its greatest amounts in the shoots were found in July (13%), and in leaves - in June (11%) In the later period the starch contents in the shoots and in the leaves are decreasing. Participation of shoot photosynthesis in the starch formation was discussed. It can be assumed that starch occurring in the bark in a considerable extent represents the assimilate production in situ. On the other hand the starch occurring in the wood derives mainly from transported assimilates.