. Elementary botany. Botany. Fig. 104. Pea seedlings; the one at the left had nu oxygen and little growth took place, the one at the right A second jar with water in the bottom instead in oxygen and growth - , . 1111 . was eWdent. of the germinatmg peas should be set up as a check. Damp folded filter paper should be supported above the water, and on this should be placed one- half dozen peas with roots of the same length as those in the jar containing carbon dioxide. 228. In 24 hours examine and note how much growth has taken place. It wdU be seen that the roots have elongated but very little
. Elementary botany. Botany. Fig. 104. Pea seedlings; the one at the left had nu oxygen and little growth took place, the one at the right A second jar with water in the bottom instead in oxygen and growth - , . 1111 . was eWdent. of the germinatmg peas should be set up as a check. Damp folded filter paper should be supported above the water, and on this should be placed one- half dozen peas with roots of the same length as those in the jar containing carbon dioxide. 228. In 24 hours examine and note how much growth has taken place. It wdU be seen that the roots have elongated but very little or none in the first jar, while in the second one we see that the roots have elongated consider- ably, if the has been carried on carefully. Therefore in an atmosphere devoid of oxygen very little growth will take place, which shows that normal respira- tion with access of oxygen (aerobic respiration) is necessary for growth. 229. Another way of perform- ing the experiment.—If we wish we may use the following experi- ment instead of the simple one indicated above. Soak a handful of peas in water for 12-24 hours, and germinate so that twelve with the radicles 20-25 '""^ ^o^^g ^^J. Fig. 105. Experiment to show that growth takes place more rapidly in presence of oxygen than in absence of oxygen. The two tubes in the vessel represent the condition at the beginning of the experiment. At the close of the experiment the roots in the tube at the left were longer than those in the tube filled at the start with mercury. The tube outside of the vessel represents the condi- tion of things where the peas grew m ab- sence of oxygen; the carbon dioxide given off has displaced a portion of the mercury. This also shows anaerobic respiration. be selected. Fill a test tube with mercury and carefully invert it in a vessel of mercury so that there will. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability
Size: 1445px × 1728px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, bookpublisher, booksubjectbotany
