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Measuring Osmotic Sap Water Potential

Sometimes networking with new scientists at conferences and workshops can pay dividends in terms of new ideas. Steve Garrity and I recently attended and taught practicum sessions at the PEPg (Plant Environmental Physiology group) Ecophysiology Workshop. The mission of this workshop was twofold: to invite the world experts on plant physiology measurements to come and lecture, and to invite the manufacturers to teach about instrumentation and provide hands-on training.

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Workshop participants check the water potential of soil with a UMS T5 mini-tensiometer.

With three sessions per day using METER instrumentation and only two of us, neither Steve nor I could teach about leaf water potential using the WP4C chilled mirror dew point instrument. So, we asked another scientist who is an expert in plant water relations to teach it for us.  Not only did he do a great job of teaching about measuring leaf water potential using a hygrometer, but he also inspired us to take another look at how to make this measurement as we learned about its importance to his research (to learn more about how to do this, watch our virtual seminar).

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He’s developed a procedure where you can freeze the leaf and break all of the cells so you are left with the cell water (the symplastic water).

Later in the conference, this same scientist gave a talk about the importance of osmotic potential.  He’s developed a procedure where you can freeze the leaf and break all of the cells so you are left with the cell water (the symplastic water).  He was able to squeeze that sap out and test it in a thermocouple psychrometer, where he established a relationship between how tolerant plants are for drought and what their osmotic sap water potential (turgor loss point) was. We have made many of those sap measurements but had not used them in this manner. That’s really interesting to us at METER because we were unaware of this relationship, and we have now found another use for osmotic potential measurements in leaves.

We would never have realized this new idea without the help of our colleague.  Meeting with other scientists at conferences and talking over ideas can be really important.  Have you ever struck gold in terms of coming up with new ideas for research, funding, or inventing new research tools at a conference you’ve attended?

Download the “Researcher’s complete guide to water potential”—>

Download the “Researcher’s complete guide to soil moisture”—>

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