ADVANCED MICROSCOPY IMAGING OF PHLOEM PROTEINS IN ARABIDOPSIS REVEAL INSIGHTS INTO MUNCH'S PRESSURE FLOW HYPOTHESIS

Thesis (Ph.D.), School of Biological Sciences, Washington State UniversityPhloem proteins have been widely regarded as a wound response mechanism. All imagery showing apparent occlusions of this protein at a sieve plate have been dismissed as preparation artifact and ignored. Unfortunately, these images only show one still frame of a movie and so all conclusions are susceptible to misinterpretation. Presented here is a combination of high resolution still images with complete context from a dynamic in vivo reference. This new perspective shows that not only are the Sieve Element Occluding Related (SEOR) phloem protein agglomerations in Arabidopsis common in healthy, translocating, uninjured plants, but that they do not appear to occlude the phloem at all. The previously known purpose of this very common family of proteins is once again obscure.School of Biological Sciences, Washington State Universit