Lab 6_ SEEDS, SEEDLINGS AND THE PLANT FORM
One of the most striking characters of the higher vascular plants is their production of seeds. Hence the
commonly used name “seed plants” for the gymnosperms (pines and other conifers, etc.) and the
angiosperms (flowering plants). Because the seed represents such a marvelous evolutionary adaptation
for the protection of the embryonic plant, and also because it is commonly regarded as the starting point
of a plants life, we will begin our study of plant form at this stage.
I. THE DICOT SEED AND SEEDLING
Obtain one dry and one soaked bean seed. Examine both under a dissecting microscope and note the
following external features. Comment below on the function and/or cause of each part.
seed coat – The seed coat is formed form the embryo sack wall and the endosperm tissue. It is
impermeable o water and gases. It is the outermost protector of the seed
hilum – The hilum is the scar left by the stalk where the ovule (seed) attached to the ovary wall
micropyle – The micropyle is a tiny pore that admits water to the embryo before the seed can become
active
Using forceps and/or teasing needle, carefully remove the seed coat from the soaked seed. Separate
the two fleshy halves (the cotyledons) and inspect the inner surfaces. One of the two cotyledons should
have the embryo plant axis still attached to it. Note the scar on the embryo axis where the other cotyledon
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