wild plants/cultivated plants

[Rick]

Also looking at insitu leaf tissue data, I see that species which are often deciduous and have extra-floral nectaries to promote ant defenses often have elevated K (K is needed for high sugar production).

So you may see higher tolerance for K in some species that may be in the vicinity of arboreal ant colonies (maybe villosum and lowii???), while species with exposed roots on limestone cliffs never experience higher K, and have not developed the tolerance.

 

[Erythrone]

Very interesting comments, Rick!

 

[Stone]

However, reducing K to my exul (which I've had since 2002) produced leaves at least 20% (up to 40%) bigger in the exact same bright spot in my GH.

I can see no process by which a reduction in K leads to 20 to 40% increase in leave size. Perhaps you have a theory?

 

[Rick]

I can see no process by which a reduction in K leads to 20 to 40% increase in leave size. Perhaps you have a theory?

Overall chronic toxicity (stunting). The exul wasn't the only one to experience this.

I did note in that old Cornell article you supplied that the fastest growth for the Cattleya's was actually for the lowest K offered. Increasing the K did not produce a bigger/faster growing plant.

As for mechanisms??? In general agro data indicates that high K is antagonistic to a laundry list of other macros and micros. Calcium is at the top of the list, and with low Ca it's hard to build strong healthy cell walls and large leaves with good structural integrity. But we've gone over this all before.