Leaf thickness between 0 - 2 mm
Stem diameter between 1 - 2 mm
Stem diameter between 2 - 6 mm
In the morning, transpiration increases. At that time, the roots cannot supply enough water and the plant uses its internal water reserves from the stem to meet the transpirational demand. As a result, the stem diameter shrinks.
At the end of the day, transpiration decreases, and the plant is able to refill its internal reserves. This causes the stem diameter to increases again.
During the night, a positive pressure in the stem cells allows the plant to grow.
Sap flow was measured using a miniature sap flow sensor (not part of the PhytoClip product).
Nearly one-to-one relationship between leaf and (thick) stem PhytoClip measurements.
Measurements were performed on the same small tomato plant.
The thick stem PhytoClip was placed at the base of the plant and the leaf PhytoClip on one of the leaves further to the top.
Simultaneous shrinking and swelling of both the diameter and leaf thickness can be observed. As well as leaf and stem growth during the night.
Measurements were performed on a small tomato plant grown outside during a heatwave.
Maximum atmospheric VPD (vapour pressure deficit) is indicated for each day.
Notice the increased daily shrinkage of leaf and stem due to the increasing VPD.
Daily growth of leaf and stem also slows down.