. Essentials of biology presented in problems. Biology. Diagram of a. root hair: CM, cell membrane; '. cell sap ; (^11", cell wall; iV, nucleus; 5, soil particles. P, protoplasm ; material, formed by the activity of the hving substance of the cell. The root hair is a living plant cell with a wall so delicate that water and mineral sub- stances from the soil can pass through it into the interior of the root. How the Root absorbs Water. — The process by which the root hair takes up soil water can better be understood if we make an artificial root hair large enough to be easily seen. An e
. Essentials of biology presented in problems. Biology. Diagram of a. root hair: CM, cell membrane; '. cell sap ; (^11", cell wall; iV, nucleus; 5, soil particles. P, protoplasm ; material, formed by the activity of the hving substance of the cell. The root hair is a living plant cell with a wall so delicate that water and mineral sub- stances from the soil can pass through it into the interior of the root. How the Root absorbs Water. — The process by which the root hair takes up soil water can better be understood if we make an artificial root hair large enough to be easily seen. An egg with part of the outer shell removed so as to expose the soft membrane under- neath is an example. Better, a root hair may be made in the following way: Pour some soft celloidin into a tube vial; carefully revoh'e the ^'ial so that an even film of celloidin dries on the inside of tlie vial. This is removed, filled with white of egg, and tied over the end of a rubber cork in which a glass tulie has previously been inserted, ^^llen placed in water, it gives a very accurate picture of the root hair at work. After a sliort time water begins to rise in the tube, having jiassed through the film of cel- loidin. If grape sugar, salt, or some other sub- stance which vnW dissolve in water were placed in the water outside the artificial root hair, it could soon be proved by test to pass through the wall and into the liquid inside. Osmosis. — To explain this process \\(^ must remember that gases and liquids of ilifi'erent densities, when sejiaiated liy a membrane (a delicate porous lining ha\ing no holes visible to the highest power microscdpe we possess), tend to flow toward each other and mingle, the greatest flow a!wa>s being in the direction of the medumi. The pmcfuf: hi/ irhich two gases or fluids, separated by a invinbrune, pass Ihrouyli the iiiciii-. An artificial root hair, showing os- mosis taking Please note that these images are extracted from scanned p
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectbiology, bookyear1911
