#nucellar embryony

[water-when-dry]

Several of the key lime seeds are turning out to be polyembryonic! That means that for each set of (fraternal) twins one is a clone of the parent plant, and the other should be a unique, sexually produced individual. Now I have to try and grow these limes to bearing age so I can figure out which is the clone - although I vaguely remember someone, maybe biodiverseed, posting about how polyembryonic seedlings will show differences in growth and vigour. I can’t find anything in the archives though so I could be making it all up.

I finally found a tangelo that was full of seeds, so I planted them today. As I was peeling the outer shells off the seeds I noticed that they appeared bumpy, like there were several sets of dormant cotyledons - I wouldn’t be surprised if they turn out to be polyembryonic as well, with at least 3 embryos per seed.

So far the lemons seem to be regular, single embryo seeds. I haven’t seen any growth yet from the meyer lemon seeds, but it took almost 3 weeks for my first batch of citrus seeds to emerge.

[southcarolinawoman]

Nucellar embryony (notated Nu+) is a form of seed reproduction that occurs in certain plant species, including many citrus varieties. During the development of seeds from plants that possess this genetic trait, the nucellar tissue which surrounds the megagametophyte can produce additional embryos (polyembryony) which are genetically identical to the parent plant. These nucellar seedlings are clones of the parent. By contrast, zygotic seedlings are sexually produced and inherit genetic material from both parents. Zygotic and nucellar embryos can occur in the same seed, and a zygotic embryo can divide to produce multiple embryos.[1]

Nucellar embryony is important to the citrus industry, as it allows for the production of uniform rootstock which yields consistent results in fruit production. However, this trait can interfere with progress in cross-breeding; most commercial scion varieties produce mainly nucellar seedlings which do not inherit any of the traits of the "father" plant.