Carbohydrate metabolism during a diurnal cycle of sorghum grown under water deficit using a network approach

Abstract

The alterations in light intensity that occur during the day and night are determinant in plant growth. The presence or absence of light is the main factor that influences photosynthesis rate and, consequently, interferes in plant carbon gain. During the day, photosynthesis is the process that provides energy and regulates the metabolism. During the night, the metabolism is maintained from the carbon accumulated during the day. To maintain the plant growth, the carbon production and utilization should be synchronized between source and sink. The source-sink relationship can also be influenced by other factors besides the light intensity. Some examples are water deficit and plant developmental stage. However, there is a few knowledge about the variation during the diurnal cycle of carbohydrates in grasses and about the interference that the developmental stage and water stress can cause in this cycle. In this sense, the objective of this proposal is to evaluate the diurnal variation of non-structural carbohydrates accumulation in sorghum plants grown under water deficit during two developmental stages. This study will increase the knowledge about the diurnal cycle in carbohydrates of grasses and also will provide data that will support experiments from Microsoft-FAPESP Project (Grant nÚ 2011/52065-3), especially related with data analysis that is the focus of this Project. To access the objective of the present proposal, sorghum plants (grass model chosen to be used in Microsoft-FAPESP Project experiments) will grow under water irrigation or water suspension. Two harvests will be made during 24 hours in two different developmental stages in which leaves, stem and roots will be sampled to non-structural carbohydrates quantification. Simultaneously, we will measure photosynthesis rate and leaf water potential. The data will be analyzed by graphs and tables and also using the networks, an approach that is being development during the Microsoft-FAPESP Project. (AU)