Ecological and Physiological Studies on the Vegetation of Mt. Shimagare VII

Analysis of Production Processes of Young Abies Stand Based on the Carbohydrate Economy

Abstract

The economy of carbohydrates was analysed in relation to the growth and the dry matter production of Abies stand about 15 years old in the subalpine zone of Mt. Shimagare, Nagano Prefecture, central Japan. Seasonal changes of sugar, starch and hemicellulose contents in needles, branches, stems and roots were pursued. Combining these results with those of seasonal growth and respiratory activity of each organ, balance sheets of matter economy of the community were constructed.
Three phases were recognized in the annual cycle of matter economy of the community. In the 1st phase, May and the early half of June, the plants did not
show any growth, and about a half of the matter produced by photosynthesis was accumulated in the old organs and the rest was consumed by respiration. In the 2nd phase, from mid-June to late August, new organs grew rapidly depending partly on the conversion of carbohydrates reserved in the old organs. In the 3rd phase, from September to late November, most of the photosynthetic products were reserved for the use in the next year.
From these analyses, the role of the evergreen leaves in the habitat of severe winter was elucidated as follows; a) they play a role as the reserve organ of large capacity in winter, and b) they recover rapidly their photosynthetic activity in early growing season to accumulate reserves, in addition to those of the winter season, before buds break from dormancy. These reserves guarantee the subsequent rapid growth of new organs in early summer.