Palea (botany)

For the city in Equatorial Guinea, see Palea.

Palea, in botany, has two separate meanings. It may be used as an alternate term for one of the receptacular bracts found in the family Asteraceae. Otherwise, it refers to one of the bract-like organs in the spikelet of the grass family, Poaceae.

Asteraceae

Known collectively as "chaff", the paleas, when present, each subtend one of the florets that cover the upper surface of the receptacle.

Poaceae

The palea is the uppermost of the two chaff-like bracts that enclose the grass floret (the other being the lemma). It is often cleft at the tip, implying that it may be a double structure derived from the union of two separate organs. This has led to suggestions that it may be what remains of the grass sepals (outer perianth whorl): specifically the two adaxial members of the three membered whorl typical of monocots. The third member may be absent or it may be represented by the lemma, according to different botanical interpretations.

Parts of a single grass spikelet, consisting of two glumes, four fertile florets, with one additional central floret that may or may not be sterile

The perianth interpretation of palea is supported by the expression of MADS-box genes in this organ during development, as is the case in sepals of eudicot plants.[1]

Footnotes and references

  1. ↑ Prasad, K, et al. (2005) OsMADS1, a rice MADS-box factor, controls differentiation of specific cell types in the lemma and palea and is an early-acting regulator of inner floral organs. The Plant Journal 43, 915–928


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