Dear Bibek, my opinion is that a penetrometer will not give you the result you are looking for. I would suggest to determine toughness of leaves you may use a texturometer equipped with a kramer shear cell. A volodkevich probe might do the job as well. But I would go the kramer shear cell if available. Best regards, Rjbender

Thank you Renar Joao Bender for your suggestion. Unfortunately, as a undergrad texturometer will not be affordable and accessible to me. Dhanyabad!!

Dear Bibek,

Basically, leaf toughness is not very common to check, however, some researchers are quite intensively working on this topic. Great article and comprehensive work of a group of researchers you can see on this link. http://bio.mq.edu.au/ ~iwright/pdfs/OEL11.pdf

Regarding leaf toughness measure – According to my experience, you can use a penetrometer to make this experiment. We had this trial of hazelnut leaves to the identification of leaf blade resistance to the strong wind.

Use regular digital or regular penetrometer, and put their 11 mm or 20 mm or 35 mm puncture tips. The bigger is sometimes better, depending on the leaves. With Small diameter tips, it is sometimes difficult to measure exactly, toughness is damaged very quickly and measurement is not adequate.

The procedure is like this:

· Take 1 thin ( for hazelnuts was taken 3-5 mm height, 15 cm width, 15 cm length ) plywood desk, with more size than leaves which needed to measure.

· Make a drill hole that is a little more diameter than the puncture tip (for instance if you take 3.5 mm tip, make a hole 3.6-3.7 mm)

· Make exactly the same size, another desk with the same hole.

· Put leaves between these two desks, and avoid veins for measurement place.

· In the hole, you can use a penetrometer and measure till of damage leaves

· Make measurements in 4 places (in our cases on hazelnut big leaves it was possible)

· Calculate average measurement. Basically, 1 kg/cm2 is around 100000 Pa, more exactly 98066.5 Pa, and 1 kg/cm2 = 0.1 MPa or more exactly 0.0980665 MPa

Best regards,

Zviad Bobokashvili

Thank you Zviad Bobokashvili for your suggestions. It's gonna be a great help for me.