The thesis is almost done. I've finished all of the research, and most of the writing. I hope to have a completed first draft on my advisor's desk Monday morning. Everything came out very cleanly...maybe publishable someday...we'll see. Another prof. of mine decided to submit an unrelated paper I've been working on to the Journal of Evolution (slim chances...but exciting nonetheless). For those interested, I'll post the abstract for my thesis below:
The extent to which hydraulic limitation of tree height can be applied as a general constraint to growth is incompletely understood. To test the hydraulic limitation theory’s regional applicability, four mature White Pine trees (Pinus strobus) in Northern Minnesota, approaching the regional species-specific height maximum, were analyzed for the presence of two water stress signatures with height: water potential gradients and carbon isotope discrimination (13C). Midday water potentials decreased with height, reaching pressures approaching -2.0 MPa at the top of each canopy. The water potentials measured may be sufficiently negative to induce stomatal closure and inhibit photosynthesis in the upper fraction of the canopies. Carbon isotope analysis results showed decreasing 13C discrimination with height, indicative of stress-induced stomatal closure over longer time scales. The results are consistent with the hydraulic limitation hypothesis and suggest that the regional asymptotic maximum height of Pinus strobus may be strongly constrained by water relations.
HOOOWAAA!!!
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2 comments:
congrats cousin john! we are celebrating for you and with you--what a great accomplishment. And now...? Off to other great adventures I have no doubt. Make sure you take time to stop by Duluth. The homebrew is waiting (as well as some maple syrup we just boiled!)--love, cousin julie
hello, i am also currently examining hlh in an undergrad research project. our study also focuses on Pinus strobus, and in the same hardiness zone. Would you be willing to email me your complete article so that I may examine your findings and site it in my paper?
thanks much.
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