Babst, BenjaminUniversity of Minnesota Duluth. Department of Biology2015-01-282017-04-142015-01-282017-04-142015https://hdl.handle.net/11299/186055Presentation by Dr. Benjamin A. Babst Assistant Scientist Biosciences Department Brookhaven National Laboratory Upton, NYPlant growth, morphology, and fitness are dependent on allocation of carbon and nutrients to specific growing sink tissues and partitioning to particular biochemicals at specific times during development. Experimental manipulations suggest that carbon fixation and sink carbon utilization are tightly co-regulated; maintenance of high photosynthetic rate is dependent on the rate of carbon utilization and/or capacity for carbon storage of sink tissues. Although the crosstalk between source and sink tissues occurs in part through phloem transport from source to sink, we still do not fully understand the mechanisms driving phloem transport or the regulation of those mechanisms. I will discuss our recent results using a combination of functional genomics, biochemical, and physiological approaches to develop a mechanistic understanding of carbon transport and allocation to different tissues, and the regulatory system that coordinates photosynthesis and carbon allocation. For example, the prevailing model of phloem transport, the Munch pressure-flow hypothesis, requires loading of osmolytes - primarily sugars - into the phloem to drive sap flow. Using a previously characterized maize sucrose transporteri (suti) knockout mutant, we found that phloem sap transport speeds were only moderately reduced from 1.5 m/hr to 0.75-1.0 m/hr, despite the near elimination of carbohydrate export from suti leaves (95-99%). While our results suggest that loading of sugars into the phloem does indeed have an impact on phloem sap flow, sugar loading only accounted for 25 - 50% of the force driving sap flow. In addition to studies of carbon transport and allocation, I will discuss new and future directions, including a focus on nitrogen transport, and determining the mechanisms that regulate carbon and nitrogen transport under the stressful environmental conditions that plants frequently encounter.en-USPostersBiology SeminarsUniversity of Minnesota DuluthDepartment of BiologyOther