- Aleurone
Aleurone (from Greek "aleuron", flour) is a
protein found in protein granules of maturingseed s andtuber s. The term is also used for the outermost cell layer of theseed coat , the aleurone layer.Aleurone protein
Aleurones can have two different morphological features, homogenous and heterogeneous. The homogenous aleurone consists of similar protein bodies (e.g. "
Phaseolus vulgaris ") while the heterogeneous aleurone consists of granules of different shapes and types of proteins covered with a membrane (e.g. "Ricinus communis ").Aleurone tissue
The aleurone layer surrounds the
endosperm tissue of grass seeds. In the cultivated cereals it is usually single-layered (except inbarley ). In cereals with starchy endosperm, the aleurone contains about 30% of the kernel's proteins. In multicolored corn,anthocyanin pigments in the aleurone layer give the kernels a dark, bluish-black color.During seed
germination , the plantembryo produces the hormonegibberellin that triggers the aleurone cells to releaseenzyme s for thehydrolysis of starch and storage proteins into theendosperm . The breakdown of the starchy endosperm supplies sugars to drive the growth of roots and the acrospire. This effect is inhibited by the plant hormoneabscisic acid , which keeps the seed dormant.The gibberellin effect on the aleurone is used in
brewing , specifically in the production of barleymalt where treatment ensures that a batch of barley seeds will germinate evenly.
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