Southern field crops (exclusive of forage plants) . revent the pollination of the silk by the pollen from thesame plant. Numerous experiments have shown that the removalof the tassels on half of the plants in a field does not ma-terially influence the yield. 88. Silks. — Each silk originates where a grain shouldbe borne on the cob, from which position it grows until itsouter part reaches the air, Ijeyond the tip of the free part of the silk is supplied with very minutehairs, the purpose of which is to entangle and hold thegrains of poflen. (vSee Fig. .36, A.) In case a silk fails to
Southern field crops (exclusive of forage plants) . revent the pollination of the silk by the pollen from thesame plant. Numerous experiments have shown that the removalof the tassels on half of the plants in a field does not ma-terially influence the yield. 88. Silks. — Each silk originates where a grain shouldbe borne on the cob, from which position it grows until itsouter part reaches the air, Ijeyond the tip of the free part of the silk is supplied with very minutehairs, the purpose of which is to entangle and hold thegrains of poflen. (vSee Fig. .36, A.) In case a silk fails toreceive pollen, it may continue to grow to unusual case no pollen lodges on any particular silk, no grainis formed at the point on the cob where that silk isattached. 89. Pollination. — Pollination is the transfer of ])ollento the sticky surface of the stigma, which in this case isthe silk. Along the entire length of the silk grows thepollen-tube (Fig. 36), thrown out by the pollen-grainafter lodgment on the silk. C07?.V STRrCTVEE 89. CUTKP Fig. 36. — Diagram showing Course of the Pollex-tube throughSilk to Ovary. A, section near outer end of silk, showing pollen-grain and pollen-tube ; B, section through base of silk and through young grain. (Drawing by C. S. Ridgway.; The pollination of corn is effected almost entirel}^ bythe wind, which may carry the pollen great distances. 90 SOUTHERN FIELD CROPS Hence, fields of two different varieties of corn, whichthe farmer desires to keep unmixed, sliould not he plantedat ebout the same date, within less than half a mile ofeach other, unless there be intervening woods or otherobstacles to the blowing of the pollen. 90. Impregnation or fertilization of the grain. — Theword fertilization, as used in this paragraph, does notrefer to the supplj-ing of food orfertilizing material to the of the flower consistsin the growdng of the ]iolIen-tubei along the entire length of thesilk and into the embryo-sac (
Size: 1537px × 1626px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauth, bookcentury1900, bookdecade1910, booksubjectagriculture
