Interesting environmental suggestions from members include: Unintentional chemical treatment or irradiation Antibacterial treatment—yes, chloroplasts were originally free living cyanobacteria While the chloroplast genome in flowering plants has reduced in size and number of genes from those free-living days, it remains vulnerable to anti-bacterials, as do mitochondria. Bleach None of these apply to the seeds I planted, to my yard, or to my neighborhood. In fact, I do not use sterilants of any kind, beyond the occasional scrub down with a dishwashing detergent of pots and work surfaces. My speculations are: One, that evolution has stripped some transcriptional repair capacity from the chloroplast genome, which means that more evolved groups (in this case monocots) have higher amounts of seed loss due to an inability in some percentage of embryos to assemble chloroplasts after germination. The interesting test for this one might be to look at several groups of dicot and monocot families, and compare loss of chlorophyll in seedlings. I do wonder how many orchid seeds fail to germinate and thrive, knowing that orchids have adopted a very stripped down lifestyle compared to other monocots. As they have very tiny seeds, it may not be very easy to measure this capacity in orchids! Two, that some weather conditions, such as cooler conditions in early fall, might impair embryo formation in seeds. The embryos form and seeds ripen, but some portion of those seeds were genetically impaired by less than optimal weather conditions. Plants have to be very flexible genetically, being rooted, which leads me to think less-than-optimal conditions would have to be extreme. Something to think about while winter weather struts across the northern hemisphere. Cheers, Kathleen _______________________________________________ pbs mailing list pbs@lists.pacificbulbsociety.net http://lists.pacificbulbsociety.net/cgi-bin/… Unsubscribe: <mailto:pbs-unsubscribe@lists.pacificbulbsociety.net>