Graduate School Lesson #518: low humidity kills newly grafted plants.

I am in Day 2 of a ten day biophysics project. I thought I would share with you some beautiful images of graft failure. In case you were curious, these are dying grafts 29 hours after grafting:

These plants have been placed in a growth chamber held at 25C. The average relative humidity in the growth chamber over the past 29 hours is a lethal 37%. Surprisingly, three of the Maxifort grafts have perked up since yesterday. We'll see if they make it through the next 24 hours.

In contrast, the grafts in the humidity-controlled growth chamber held at 25C and 95% humidity look fantastic:

The wilted Cherokee Purple in the right foreground is the only wilted plant out of 40 plants.

I will be measuring transpiration rate over the next 10 days. I'm excited to see what happens once the xylem of the rootstock and scion heal together. Will the transpiration rate increase? I hope I get some interesting results, especially since I only had access to one humidity-controlled growth chamber which meant sure death for my poor grafts placed in the 37% r.h. chamber.

Especially since I have spent a good 12 hours in the past three days taking painstaking measurements with a slow cumbersome leaf porometer. Trying to place wilted leaves in the sensor is like trying to fold origami with tissue paper and not recommended for those short of patience and quick of temper.