Plant Growth and Development, BO/GN 733

Agamous and germ line specification Bob and I were talking after class about agamous and germ line specification. One of the major defects of expressing wuschel instead of (or in addition to) agamous is that no anthers or ovules are formed, as far as I could see. Developmentally, I think this means leaf-like structures can emerge (carpel primordia) but if no ovules are formed, agamous MAY have an additional critical function; to specify the germ line.

Just a bit of background... you can think of ferns as being similar to angiosperms (flowering plants) but they don't hide their seeds. Spores are found underneath the fronds. If you take the leaf-like frond and roll it up, like a pea pod, you have now hidden the seeds from view and created an angiosperm (means "hidden sperm"; gymnosperms have "naked sperm" where seeds lie on top of the cone scale, a modified leaf).

Sepals, petals, and carpels have the same "body plan" as leaves. Stamens are more specialized, but one could think of them as a midvein with a microsporoctye at the end (the anther).

What causes the switch to meiosis? Does agamous control that, or is the switch downstream of something specified by agamous? (Agamous would be epistatic to the switch.)

Even though carpel-like structures are formed in some of the mutants discussed in class, if they don't make seeds they are developmentally lacking in a very important process.