. Advanced biology. Biology; Physiology; Reproduction. PRODUCTION OF THE MALE GAMETE 275 Problem. What effect has a sugar solution on pollen grains f Make up cane sugar solutions of thirty-five per cent, ten per cent, and three per cent. Take tliree hanging- drop glass slides and on each one lay a cover glass from the center of which hangs a drop of sugar solution con- taining some pollen. Use a different sugar solution for each slide. Seal the cover slip air tight by means of vaseline. (Petri dishes or Syracuse watch crystals may, also, be used.) Different pollen requires different concentrat
. Advanced biology. Biology; Physiology; Reproduction. PRODUCTION OF THE MALE GAMETE 275 Problem. What effect has a sugar solution on pollen grains f Make up cane sugar solutions of thirty-five per cent, ten per cent, and three per cent. Take tliree hanging- drop glass slides and on each one lay a cover glass from the center of which hangs a drop of sugar solution con- taining some pollen. Use a different sugar solution for each slide. Seal the cover slip air tight by means of vaseline. (Petri dishes or Syracuse watch crystals may, also, be used.) Different pollen requires different concentrations of sugar solution in order to grow. A three-per-cent sugar solution is usually needed for tulip, narcissus, and onion; fifteen per cent for sweet pea and nastm-tium. Let the preparations stand for one or two days. Then mount under the microscope. L Describe the shape of the pollen grains when first produced by the anther. IL Describe what has happened to the grains. A. These outgrowths are called pollen tubes. B. Describe the food for the pollen tubes which you have grown. III. Carefully crush the tip of a ripe stigma on a glass slide and mount under the microscope. A. Do you find any pollen grains here? 1. How did they get on the stigma? B. Do any pollen grains show pollen tubes? L In which direction are they growing? 2. Where must the germinating pollen tubes obtain their food? IV. Draw and label a germinating pollen 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 Wheat, Frank Merrill; Fitzpatrick, Elizabeth T. New York ; Boston [etc. ] : American Book Company
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