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Re: Small Leaves
>From: "Dixon, Steven T. (BEn)" <stdixon at ben_bechtel.com>
>Subject: Small Leaves
>
>Regarding whether nitrogen deficiency might cause small and deformed leaf
>growth, Ryan wrote: "I noticed some tiny and deformed leaves on some
>plants. Checking the nitrate, I found it to be zero. I'm sure there was
>plenty of calcium, potassium, and boron available to the plants. I added
>some nitrate (now 5ppm) and I'm betting things get back to normal. Any
>thoughts?"
>
>I think the answer is yes, Ryan. My first experience with this was when
>Karen Randall visited San Francisco a couple of years ago. She looked at a
>lawn-type stand of Anubias nana nana in and around some driftwood and
>immediately said that the very small leaves (they were about the size of a
>thumb nail) were due to N deficiency. I started adding enough nitrate to
>keep a few ppm in the water column between water changes and sure enough
>leaf size doubled and the new growth seemed quite healthy.
>
>In light of some of our recent conversations and especially those interested
>in more fertilization in the substrate, I wonder whether a plant such as
>Anubias would be expected to dig into the substrate to grab nutrients or is
>it more dependent upon water column fertilization? This would have been
>some time ago and my memory is not clear but I think I tried some Jobes'
>sticks pushed into the gravel and did not observe the same effects as I did
>from increase N in the water column.
In all the descriptions of N. deficiency, I have never seen anything about
new leaves, or any leaves for that matter, being distorted. The plant is
yellowish and growth is slowed. The whole plant can be small.
Anubias barteri roots can attach to stones. The air channels in the roots
are very small, compared to those of most other aquatic plants. The roots
never get very long, either, nor do they branch very much. All these
traits make me think that Anubias roots are not designed to penetrate
anaerobic mud, but to cling to surfaces. Also, A. barteri seems to grow
very well as a floating plant, never developing iron deficiency. I am
convinced that A. barteri gets its nutrients from the water. When I grow
it in gravel, I only put a tiny bit of soil with the gravel. I also have
A. afzelii, and its roots are very long and seem to be designed to go deep
into soil.
Paul Krombholz, in soggy central Mississippi, expecting some light frost
tonight.