The response of nitrate uptake at root and whole plant utilization to photosynthetic activity at shoot in Arabidopsis

Nitrate (NO3-) is one of the main nitrogen sources used in horticulture and is often used in relatively high concentrations. However, a high rhizosphere nitrate concentration is not always preferred by the roots of the plant. This is because the uptake of nitrate at root is not only determined by the external nitrate concentration that is applied to the plant. It has been studied that the photosynthetic activity at the shoot can be one of the ‘driving forces’ to the nitrate uptake at root. This could be due to several reasons, the demand of nitrogen for growth in the whole plant, the transpiration rate at root and the availability of the energy level in shoot and root. This research is focused on finding out the hidden players in the regulation of nitrate uptake at root. Arabidopsis were treated with different levels of light intensity either during the whole growth period or for half an hour, three hours or seven hours before the harvest. It is expected that the uptake of the nitrate increases accordingly to the increase of light intensity. Meanwhile, nitrate uptake is a secondary active process, suggesting that the increase uptake rate also leads to a higher energy consumption for the plant. How will the plant coordinate such an increase of nitrate uptake? A few questions are to be addressed: how does the expression level of nitrate uptake related genes change due to the higher nitrate uptake; how does the sugar metabolism in root and shoot change when there is a higher energy consumption for the expense of nitrate uptake; how does the plant utilize the nitrate taken up by root? Note that this experiment in chamber has already been carried out, samples are collected. Lab work and data analysis is the main focus of this thesis.

Used skills

You can choose between:

  1. Molecular biology (experience with Molecular Biology is appreciated), or
  2. HPLC, enzyme activities, Redox metabolism

We are looking for two students on this project!

Interested in doing a BSc or MSc thesis at HPP? Please contact the HPP student coordinator Katharina Hanika.