Morphology of Flowering Plants Question 69
69. The aleurone layer in maize grain is specially rich in
[2003]
(a) auxins
(b) proteins
(c) starch
(d) lipids
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Answer : b
Hints & Solutions
(b) The aleurone layer in maize grain is specially rich in proteins. Aleurone is a protein found in the endosperm of many seeds. It forms the outermost layer of the seed coat in some grains. During seed germination, hydrolysis in the seed causes the aleurone cells to break down into amino acids. Once triggered by hormones released from the embryo, the aleurone synthesises enzymes in order to break down the starchy endosperm supplying sugars to drive the growth of roots and germination. Aleurones can have two different morphological features, homogenous and heterogenous. The homogenous aleurone is consists of similar protein bodies (e.g. Phaseolus vulgaris) while the heterogenous aleurone consists of different shape and type of proteins covered with a membrane (e.g. Riccinus communis).
