. Essentials of botany. Botany; Botany. MOVEMENTS OF THE SEEDLING 23 29. What pushes the Cotyledons up? — A very little study of any set of squash seedlings is sufficient to show that the portion of the plant where roots and hypocotyl are joined neither rises nor sinks, but that the plant grows both ways from this part. It is evident that as soon as the hypocotyl begins to lengthen much it must do one of two things : either push the cotyledons out into the air or else force the- root down into the ground as one might push a stake down. What. Fig. 9. Successive Stages in the Life History of tli
. Essentials of botany. Botany; Botany. MOVEMENTS OF THE SEEDLING 23 29. What pushes the Cotyledons up? — A very little study of any set of squash seedlings is sufficient to show that the portion of the plant where roots and hypocotyl are joined neither rises nor sinks, but that the plant grows both ways from this part. It is evident that as soon as the hypocotyl begins to lengthen much it must do one of two things : either push the cotyledons out into the air or else force the- root down into the ground as one might push a stake down. What. Fig. 9. Successive Stages in the Life History of tlie Bean Seedling. A A, the surface of the ground; r, primary root; r', secondary root; c, hypocotyl; a, arch of hypocotyl; co, cotyledons. changes does the plantlet undergo in passing from the stage shown at A to that of B and of C, making it harder and harder for the root to be thrust downward? 30. Use of the Peg. — Squash seedlings usually (though not always) form a sort of knob on the hypocotyl. This. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Bergen, Joseph Y. (Joseph Young), 1851-1917. Boston, Ginn
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