Medini Weerasinghe

Designing Poplar and Willow plants for increased Nitrogen and Carbon assimilation and Biomass yield
Medina Weerasinghe

Biological Sciences: Integrative and Organismal Biological Sciences - PHD
Email address:

Advisor: Dr. Subhash Minocha; advisor's website

Oxidized and reduced forms of nitrogen are the most common and costly input nutrient that often limits carbon assimilation in plants. The forms of nitrogen present in plants are nitrate and ammonium, which are very mobile in the soil. N (especially as NO3) is also the cause of significant environmental pollution. The dramatic increase in N fertilization, which plays a crucial role in increasing crop yield, has challenged the farmers to focus on the most effective ways of applying N while avoiding NO3 pollution.

As important as N is for the plant, the predominant component of the plant biomass is C. Carbo assimilation through photosynthesis plays a critical role in inorganic N usage in leaves and the partitioning of assimilated carbon between organic acids, starch and sugars is markedly affected by N availability.

Previous studies conducted in our lab has revealed the effectiveness of enhancing both N and C accumulation through genetic manipulation of a group of metabolites called polyamines in transgenic cells (of poplar NM6) and plants (of Arabidopsis thaliana) through increased putrescine production. The primary goal of my research is to produce transgenic plants of poplar with genes that regulate polyamine biosynthesis.