Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 1 of 1
Full-Text Articles in Life Sciences
Age-Related Trends In Red Spruce Needle Anatomy And Their Relationship To Declining Productivity, Margaret H. Ward
Age-Related Trends In Red Spruce Needle Anatomy And Their Relationship To Declining Productivity, Margaret H. Ward
Electronic Theses and Dissertations
Many species of trees undergo predictable age-related changes in foliar morphology and physiology. Age-related declines in photosynthetic rates, which may lead to decreases in productivity, have been described for numerous species. However, the physiological basis for these phenomena is unclear, as are linkages between agerelated trends in morphology/anatomy and physiology. Photosynthetic capacity in red spruce (Picea rubens Sarg.) may result from increased mesophyll resistance to CO2 uptake in older trees. Additional studies with other species imply that the foliage of older trees may have a lower ratio of photosynthetic to non-photosynthetic tissue and a larger proportion of xylem to leaf …