. Elementary principles of agriculture; a text book for the common schools. Fig 12. Root-hairs of corn seedling withsoil particles adhering closely. Fig. 11. Seedlings ofmustard. A, withparticles of soil cling-ing to root-hairs. removal of soilby a stream of Sachs. sand or sawdust-hairs hold the soilparticles to theroot. When theroots are growingin moist air, theyare straight; butin the soil thehairs apply them-selves very closelyto the soil parti-cles. (Fig. 13.)The water ab- 14 Elementary Principles of Agriculture Borbed by the root is first taken in by the
. Elementary principles of agriculture; a text book for the common schools. Fig 12. Root-hairs of corn seedling withsoil particles adhering closely. Fig. 11. Seedlings ofmustard. A, withparticles of soil cling-ing to root-hairs. removal of soilby a stream of Sachs. sand or sawdust-hairs hold the soilparticles to theroot. When theroots are growingin moist air, theyare straight; butin the soil thehairs apply them-selves very closelyto the soil parti-cles. (Fig. 13.)The water ab- 14 Elementary Principles of Agriculture Borbed by the root is first taken in by the seedUngs may be growing in soil so dry that watermay not be pressed out of it, still, the soil particles arecovered with a film of moisture from which the rootsabsorb their supply. (See Fig. 39.) 23. How the Root Grows. The root grows only at thetip. The tip does not grow straight through the soil,. Fig. 13. Diagram of a portion of soil penetrated by root-hairs, h, h\ arisingfrom root. t. At z. s, s the hair has grown into contact with some of thesoil particles, T, which are surrounded by water films (shaded by parallellines). After Sachp, but bends to and fro in a sort of circle, takingadvantage of the small openings between the soil par-ticles. It is covered with a delicate root-cap. As theroot lengthens, the cells of the cap are rubbed off, butnew ones are formed to take their place. Only the regionin front of the root-hairs has the power of lengthening.(Fig. 14.) 24. Absorption of Water by Seeds. Seeds absorbwater from the soil particles. When dry seeds are placedin a bed of moist sand or loam, the little film of moisturethat covers the soil ^articles is absorbed by the seeds. How Seedlings Get Established 15 Seeds will not absorb enough water from moist air tomake them germinate. They must be in contact witha substance covered with a film of water. 24a. The Swelling of Seeds
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectagriculture, bookyear
