Xenia

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Xenia

(zē`nēə), city (1990 pop. 24,664), seat of Greene co., SW Ohio; inc. 1814. It is a trade and industrial center in a farm area. The city has food-processing plants, and transportation equipment, plastics, and machinery are among its manufactures. The county historical museum is there. A tornado destroyed about half of the city on Apr. 3, 1974.

Xenia

 

a seed or fruit distinguished from other seeds or fruits of the same plant by its color, form, size, or other features.

The formation of xenias is the result of the influence of genes of the male parent on features of the endosperm (first order xenia) or on the surface of the seed and the seed cover (second order xenia, or metaxenia). The term was introduced by the German biologist W. Fokke (1881), although the phenomenon had been noted by many naturalists before then. Only after the discovery of double fertilization by the Russian botanist S. G.Navashin (1898) did it become clear that xenias were the result of the combination of a second sperm with the nucleus of the central cell of the embryonic sac (while the first combined with the egg cell).

Therefore, the dominant features of the endosperm cell of the male plant would appear in the endosperm of hybrid seeds formed in the female plant. For example, if a female corn plant has white “seeds” (that is, grains), which are determined by the color of the endosperm (a recessive homozygote), and the sperm introduces a dominant gene determining a yellow coloration of the seeds (a dominant homozygote), then the hybrid seeds will be yellow, or xenian. Metaxenias have been described for many plants, but the reason for their development is unclear.