I've seen very few achlorophyllous seedlings except in a batch of Hemerocallis seeds sent me by a friend, of which at least 20% of the seedlings had no or almost no chlorophyll. I say it that way because some died very quickly, presumably as soon as the energy from the endosperm was exhausted, while others continued to grow, weakly, for as much as a month. I assume that even though they all looked the same to me those longer lasting ones did have some small amount of functional chlorophyll and chloroplasts. In theory one could grow on achlorophyllous seedlings indefinitely by supplying energy via sugars, but the only paper I could find (my Google-fu seems weak this morning) was from Knudson in 1919 on corn, and he found that even in vitro with sucrose those seedlings didn't thrive. Our experience with orchids matches yours (my wife does all our flasking). Hybrid Cattleyas germinate like grass seed, even after years of storage, I presume as a result of selection pressure for that. The tuberous terrestrial species I like are more difficult, but even there, when we do get germination I don't recall ever seeing an achlorophyllous seedling. That seems odd to me now. Steve On 2/16/2021 1:04 PM, Robert Lauf via pbs wrote: > Back when I was flasking my orchid seeds, as I recall, as soon as they germinated, they turned green and you would see all these tiny green flyspecks. At the protocorm stage, they were several mm in diameter (these were mainly cattleyas). Any that didn't have chloroplasts would have been white but should continue to grow in the medium, relying on the sugar in the mix. I don't recall seeing much if any of that behavior, and certainly in the replate medium, where they would develop into plantlets, I didn't see white plants, and that medium also contained sugar. At the same time, there were plenty of seeds that never developed at all. But with a hundred thousand seeds or so, there was no shortage, unless the entire pod was a dud. > > It is interesting that orchids chose to make tiny seeds with no endosperm so they could be wind-dispersed, whereas the bromeliads that they share the trees with chose to make normal seeds and rely on parachutes to keep them airborne. Reminds me of two student teams independently engineering their solutions to the same problem. > > Bob > > > _______________________________________________ > pbs mailing list > pbs@lists.pacificbulbsociety.net > http://lists.pacificbulbsociety.net/cgi-bin/… > Unsubscribe: <mailto:pbs-unsubscribe@lists.pacificbulbsociety.net> _______________________________________________ pbs mailing list pbs@lists.pacificbulbsociety.net http://lists.pacificbulbsociety.net/cgi-bin/… Unsubscribe: <mailto:pbs-unsubscribe@lists.pacificbulbsociety.net>