Abstract
Stomatal conductance, the reciprocal of stomatal resistance, represents the gas exchange ability of stomata. Generally, the stomatal conductance is higher when stomata open wider, and vice versa. In this protocol, we describe how to measure stomatal conductance in rice using Li-6400 (Licor, USA).
Keywords: Stomatal conductance, Li-6400XT, Rice, Red light, Blue light
Background
Stomata consist of a pair of guard cells and open in response to blue light as a signal. Using epidermal fragments from the kidney-shaped guard cells (found mainly in dicots), the blue light-induced stomatal opening can be observed readily under a microscope. However, direct measurement of the stomatal aperture from the dumbbell-shaped guard cells in monocots, such as rice, maize, wheat, and oats, is very difficult, due to their uneven leaf surface. Thus, a gas-exchange system is useful for the measurement of blue light-induced stomatal opening in the leaves of monocots.
Materials and Reagents
Equipment
Procedure
Note: Data in steps 9 and 10 are recorded by Auto Program.
Data analysis
The stomatal conductance is calculated automatically by the software of the instrument. Select the ‘Obs’ column (refers to the number of objects logged in this experiment) and ‘Cond’ column (refers to the stomatal conductance), using the Chart tool to make a scatter (x, y) chart (Figure 4). Because the objects were logged every minute, the chart reflects the time course of changes in stomatal conductance. Figure 4. Data analysis of stomatal conductance. Select the highlighted columns ‘Obs’ and ‘Cond’ to make a scatter (x, y) chart. The red arrow and blue arrows show the points when the light sources were switched on and off.
Notes
Acknowledgments
This protocol was adapted from Toda et al. (2016). This work was supported in part by Grants-in-Aid for Scientific Research from the Ministry of Education, Culture, Sports, Science and Technology, Japan (15H05956 to T.K.), and by the Japan Science and Technology Agency [the Advanced Low Carbon Technology Research and Development Program].
References
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