Question

Xenia and metaxenia terms are related to
A. Pollen culture
B. Only endosperm
C. Xylem and phloem
D. Pollen and endosperm

Answer 1

Hint: The phenomenon deals with the effects of pollen acquired from different sources on some specific characteristics exhibited by seeds and fruits in a variety of species.

Complete answer:
Xenia is defined as the direction effect of the pollen grains (male parent) inside the embryo sac except for embryo (i.e. on the seeds and fruits, outside the embryo) whereas Metaxenia is the effect of pollen grain on the testa and pericarp which are present outside the embryo sac. Metaxenia is the specific case of xenia which occurs only in maternal tissues. The Metaxenia effect is produced due to hormones produced by the embryo and endosperm after double fertilization. Metaxenia is triggered by a signal from the tissues bearing paternal genes. Maize and date palm are examples of xenia and metaxenia respectively.
The function of the xenia and metaxenia is to identify the best pollinizer parents to decrease the fruit development period and to increase yield in mixed cultivar plantings.
Both xenia and metaxenia are based upon a Greek root, xenos, meaning “a foreigner or guest.” In Greek, the word xenia is an abstract noun meaning “hospitality.” The prefix meta- means “beyond, behind, or after,” or it can indicate a change or transformation, as in “metamorphosis.”
So, the correct answer is (d) ‘Pollen and endosperm’.

Note:
- Wilhelm Focke defined the term xenia in 1881.
- Swingle gave the term metaxenia in 1928.
- Xenia and metaxenia effects are shown by angiosperms.