Niklas, Karl , Christianson, Michael , Cobb, Edward .
The scaling of area versus mass of leaves sorted by the different morphologies of Sassafras albidum.
The relationship between the surface area of a leaf (A) and its dry mass (M) quantifies the photosynthetic dividend resulting from a specific carbon investment. Consequently, this relationship has been intensively studied. Structured collections of canopies, however, indicate that random samples of representative leaves may be missing important information. We illustrate this concern using Sassafras albidum, a dioecious species that produces different types of shoots bearing one or more of three leaf morphologies (one-lobed, bilobed, and trilobed). A total of 319 leaves was gathered from trees growing in a canopy understory and in an open area and measured for A and M. Statistical analyses show that (1) leaves from trees growing in the understory had significantly larger A for their M than the leaves gathered from trees growing in full sun, (2) while all three leaf morphologies introgress in terms of the scaling of A vs. M, the three leaf morphologies are statistically distinct and (3) the slope of the A vs. M relationship is less than one. These results extend our conclusions from studies of Ginkgo biloba and Acer rubrum, i.e., analyses of the scaling of A vs. M require careful attention to differences among the types of shoots in a canopy and their location regarding ambient light conditions, not random samplings of leaf populations. The results also illustrate the phenomenon called diminishing returns (i.e., the scaling of A vs. M is less than one), which adds Sassafras to the list of taxa where larger leaves represent less efficient investments of carbon.
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1 - Cornell University, Plant Biology, 412 Mann Library, ITHACA, NY, 14853-5908, USA
2 - University of California, Davis, Department of Plant Sciences, Davis, CA, 95616, USA
3 - Cornell University, Department Of Plant Biology, 207 Plant Science Building, Ithaca, NY, 14853-5908, USA
specific leaf area
Presentation Type: Oral Paper:Papers for Sections
Location: Union B/Hyatt
Date: Tuesday, July 10th, 2012
Time: 2:15 PM