What is "hypocotyl"

Usage examples of "hypocotyl".

Their hypocotyls were secured to sticks, and glass filaments bearing little triangles of paper were affixed to the cotyledons of both.

In order to ascertain more accurately the nature of these movements, the hypocotyl of a seedling, with its cotyledons well expanded, was secured to a little stick, and a filament with triangles of paper was affixed to one of the cotyledons.

It is therefore not surprising that it should be inherited, at least to some extent, by plants having hypogean cotyledons, in which the hypocotyl is only slightly developed and never protrudes above the ground, and in which the arching is of course now quite useless.

They were also able, as well as the hypocotyls of Brassica, to form straight furrows in damp sand, whilst circumnutating and bending towards a lateral light.

It has already been stated that the cotyledons of Phalaris and Avena, the plumules of Asparagus and the hypocotyls of Brassica, were likewise able to displace the same kind of sand, either whilst simply circumnutating or whilst bending towards a lateral light.

In some cases, as with the hypocotyls of Brassica, the leaves of Dionaea and the joints of the Gramineae, the circumnutating movement when viewed under the microscope is seen to consist of innumerable small oscillations.

Although this movement, in its ordinary or unmodified state, appears in some cases to be of service to plants, either directly or indirectly--for instance, the circumnutation of the radicle in penetrating the ground, or that of the arched hypocotyl and epicotyl in breaking through the surface--yet circumnutation is so general, or rather so universal a phenomenon, that we cannot suppose it to have been gained for any special purpose.

Brassica oleracea, circumnutation of the radicle, of the arched hypocotyl whilst still buried beneath the ground, whilst rising above the ground and straightening itself, and when erect--Circumnutation of the cotyledons--Rate of movement--Analogous observations on various organs in species of Githago, Gossypium, Oxalis, Tropaeolum, Citrus, Aesculus, of several Leguminous and Cucurbitaceous genera, Opuntia, Helianthus, Primula, Cyclamen, Stapelia, Cerinthe, Nolana, Solanum, Beta, Ricinus, Quercus, Corylus, Pinus, Cycas, Canna, Allium, Asparagus, Phalaris, Zea, Avena, Nephrodium, and Selaginella.

The movement at right angles to the above lines was due to the arched hypocotyl becoming more arched as it increased in height.

It has already been stated that the cotyledons of Phalaris and Avena, the plumules of Asparagus and the hypocotyls of Brassica, were likewise able to displace the same kind of sand, either whilst simply circumnutating or whilst bending towards a lateral light.

The hypocotyl is slightly sensitive, so that if rubbed with a needle it bends towards the rubbed side.

But with most of the Cucurbitaceae there is a curious special contrivance for bursting the seedcoats whilst beneath the ground, namely, a peg at the base of the hypocotyl, projecting at right angles, which holds down the lower half of the seedcoats, whilst the growth of the arched part of the hypocotyl lifts up the upper half, and thus splits them in twain.

The sheathlike cotyledons of the Gramineae circumnutate, that is, move to all sides, as plainly as do the hypocotyls or epicotyls of any dicotyledonous plants.

In some cases, as with the hypocotyls of Brassica, the leaves of Dionaea and the joints of the Gramineae, the circumnutating movement when viewed under the microscope is seen to consist of innumerable small oscillations.

If the hypocotyl is exposed to a moderately strong lateral light it moves quickly towards this side, travelling in a straight, or nearly straight, line.