Like human beings, plants also need to breath. They transpire water out, and absorb CO2 at the same time. During this process, plants need to guarantee that they have enough water supply, and the sugar produced in leaves should be transported efficiently so that the concentration won’t be so high to hamper sugar translocation. Thus, the balance between water transport and water support, and between sugar production and sugar transport need to be considered. My research is mainly about to understand how plants regulate these balances and if different plant types use different strategies to keep these balances.