Life on the Farm: Plant Life |
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absorbed absorption Achillea Millefolium agency AGRICULTURAL Agrostis Agrostis vulgaris alluded ammonia salts beans branches Bromus mollis buds carbonic acid cells cereals changes character chemical chlorophyll circumstances clover constitution contain crops cultivator Darwin diminished direction effects especially farmer favourable fertilisation Festuca ovina fibre flower fluid formation fruit grain grasses gravitation green growing points grown growth heat Holcus lanatus increased influence injury leaf leaves Leguminosa leguminous plants less liquid mangels membrane mentioned mineral manures miscellaneous plants moisture molecules movements nature nitrate of soda nitrogenous manures oxygen particular Plantago lanceolata Poa pratensis Poa trivialis pollen potash potato pratensis Price produce proportion protoplasm quantity radicle result ripening root Rothamsted Rumex Acetosa season seed seedling side soil starch stem structure substance superphosphate supply surface takes place temperature tendency tion tissues tree tuber turgescence turnips unmanured plots vapour variety various varying vegetation weeds wheat woody
Popular passages
Page 60 - We believe that there is no structure in plants more wonderful, as far as its functions are concerned, than the tip of the radicle. If the tip be lightly pressed or burnt or cut, it transmits an influence to the upper adjoining part, causing it to bend away from the affected side...
Page 61 - It is hardly an exaggeration to say that the tip of the radicle thus endowed, and having the power of directing the movements of the adjoining parts, acts like the brain of one of the lower animals...
Page 61 - ... towards the centre of gravity. In almost every case we can clearly perceive the final purpose or advantage of the several movements. Two or perhaps more of the exciting causes often act simultaneously on the tip, and one conquers the other, no doubt, in accordance with its importance for the life of the plant.
Page 1 - No one will dispute his title to our gratitude ; but at the same time it must not be overlooked that the claims of him who can make one grow where none at all existed before are even greater, because the difficulties to be overcome are more formidable, for where one exists already it is relatively easy to bring about its increase.
Page 61 - ... in accordance with its importance for the life of the plant. The course pursued by the radicle in penetrating the ground must be determined by the tip; hence it has acquired such diverse kinds of sensitiveness. It is hardly an exaggeration to say that the tip of the radicle, thus endowed, and having the power...
Page 52 - The growing part does not therefore act like a nail when hammered into a board, but more like a wedge of wood, which, whilst slowly driven into a crevice, continually expands at the same time by the absorption of water ; and a wedge thus acting will split even a mass of rock.
Page 60 - ... more surprising, the tip can distinguish between a slightly harder and softer object, by which it is simultaneously pressed on opposite sides. If, however, the radicle is pressed by a similar object a little above the tip, the pressed part does not transmit any influence to the more distant parts, but bends abruptly towards the object. If the tip perceives the air to be moister on one side than on the other, it likewise transmits the influence to the upper adjoining part, which bends towards...
Page 60 - ... continually moving his head from side to side, or circumnutating, he will feel any stone or other obstacle, as well as any difference in the hardness of the soil, and he will turn from that side. If the earth is damper on one than on the other side, he will turn thither as to better hunting ground.