Identify parts of germinating trillium seed

[Robert Pavlis]

The picture is of a Trillium erectum seedling. I have been playing arornd with the use of GA3 on the seed. It definitely resulted in quicker germination. Now I am trying to see if it will cause the true leaf to develop sooner.

The picture shows a fresh seed collected in mid August and treated to GA3. Germination started around mid Oct. It was then moved to the cold on Nov 15.

I believe the green parts are the codyledon leaves--you can see the remaining seed capsule at the end of them. They had room light while they developed. Near the thickening base (tuber) I can see what might be the true leaf starting to grow.

Is my interpretation correct?

When should they be moved back into the warmth?

[Afloden]

See here; http://www.trilliumresearch.org/images/htr_web_images_research/05_ys_01_08_lg.JPG

The green part still in the seed is the cotyledon or first true leaf. The lower part is analgous to future years cataphyll (I think). Not sure about when to give them warmth again, maybe after about 30 days of cool.

[Gene Mirro]

I would transition to warm temps very gradually.  Maybe go from 5C to 10C for a few weeks and see what happens.  If you go right to 20C, I predict that you will lose the seedlings, but I can't prove that.  Maybe you should try several approaches in parallel and see which works best.

[Robert Pavlis]

I am fairly sure the green part is the codyledon--not the first true leaf.

Good idea to bring seedlings to warmth slowly, and I will try a few each week to see how they perform with different lengths of cold spell.

The small new growth near the tuber is called the bud meristem according to the reference above. I guess it will elongate and form the first true leaf. We'll see.