I

In 1980-1982, six transplant gardens were established along a latitudinal gradient in interior Alaska from Eagle Creek, AK, in the south to Prudhoe Bay, AK, in the north (Shaver et al. 1986) .Three sites, Toolik Lake (TL), Sagwon (SAG), and Prudhoe Bay (PB) are north of the continental divide and the remaining three, Eagle Creek (EC), No Name Creek (NN), and Coldfoot (CF), are south of the continental divide. Each garden consisted of 10 individual tussocks transplanted back to their home-site, as well as 10 individuals from each of the other transplant sites (n = 10; 6 populations x 6 sites x 10 replicates = 360 total individuals).

Gas exchange was measured with an LI-6400 Portable Photosynthesis System (LiCor, Inc., Lincoln, NE, USA). Six leaves from each tussock were placed across a 2 x 3 cm cuvette that was equipped with an LED light source (6400-02B, LiCor, Inc., Lincoln, NE, USA). After measurement, width of each leaf was measured with a comparator. Leaf area was calculated as the sum of the leaf widths (cm) times the length of leaves that were in the cuvette (2 cm). Afterwards the portions of the leaves that were in the cuvette wre dried for 24 hr  at 65 C and weighed. For measurements of light saturated photosynthetic rate (AMAX), cuvette conditions were set to 380 ppm CO2, 15°C, 1500 μmol m-2 s-1 PPFD, and 40-70% relative humidity. After 10 measurements of AMAX, the light was switched off and 10 measurements of dark respiration (RESP) were made at 15°C after waiting 1 minute. The median

For AMAX and RESP measured on both leaf area and dry mass basis the 10 measurements were averaged to produce a mean value for each tussock. The median value of the 10 measurements wasc calculated. Mean and median values for the stomatal conductance and the mean ratio of internal  to external CO2 concentration were also calculated.

 Shaver GR, Fetcher N, Chapin FS (1986) Growth and flowering in Eriophorum vaginatum - Annual and latitudinal variation. Ecology 67:1524-1535

Notes:
Funding for this research was provided by National Science Foundation grant ARC-0908936 with additional support from NSF-BSR-9024188.
AMAX and RESP data are incorporated in a ms. submitted to Botany. Stomatal conductance and internal CO2 data are still unpublished.