Experiments on the growth of pollen tubes and their orientability
Experiments on the growth of pollen tubes and their orientability
Mature pollen falling on the stigma will germinate and grow pollen tubes, and pollen germination can also occur when appropriate conditions (temperature, pH, osmotic pressure of the medium) are given artificially. Pollen germination and the growth of pollen tubes require a certain amount of nutrients (both organic and inorganic substances). There is a close interrelationship between the pollen grains, when the pollen density is large, the germination is faster, the growth is also better, this is the so-called "collective effect"; at the same time, the gynoecium organization can affect the direction of growth of pollen tubes, that is, the so-called pollen tubes to the chemical, which is important to the fertilization process.
Operation method
Experiments on the growth of pollen tubes and their orientability
Principle
Mature pollen falling on the stigma will germinate and grow pollen tubes, and pollen germination can also be caused by artificially giving the right conditions (temperature, pH, osmotic pressure of the medium). Pollen germination and the growth of pollen tubes require a certain amount of nutrition (including organic and inorganic substances). There is a close interrelationship between the pollen grains, when the pollen density is large, faster germination, growth is also better, this is the so-called "collective effect"; at the same time, the pistil organization can affect the direction of the pollen tube growth, that is, the so-called pollen tube to the chemical, which is important to the fertilization process. Move I. Materials and equipment For more product details, please visit Aladdin Scientific website.
1. Plant material: faucet flower (Antirrhinu M M ajus). Inflorescences with freshly opened flowers were picked in the morning and inserted in a container with water.
2. Equipment: microscope; thermostat; brush; tweezers; razor blade; gas lamp; glass goblet; coverslip; slide; 4 cm Petri dish; 9 cm Petri dish; 8 ml beaker; 50 ml beaker; pipette; dropper.
3. reagents: 4% agar; 40% sucrose solution; 0.04% H3BO4 solution; 4% yeast extract solution
Experimental Steps
1. Cultivation of pollen
(1) Coat the mouth of a small glass cup, 5 M M in diameter and 5 M M in height, with petroleum jelly or lanolin and fix it on a dry slide with 2 drops of water in the ring. Make a total of 4 such devices.
(2) Prepare medium 1 (see Table 7-1) in a small 8 ml 2 beaker, put 1 drop of medium on a clean slide with a dropper, cool it down, sprinkle a small amount of pollen from a faucet flower on the medium with a brush, and then cover the coverslip with the pollen side backwards in the small ring above it.
(3) Prepare medium 2 in another 8 ml beaker as in step 2.
(4) Prepare medium 4 in another 8 ml beaker as in step 2.
(5) Prepare medium 3 in a 50 ml beaker and place 1 drop on a coverslip as above.
(6) Pour the remaining medium 3 into two 4-cm petri dishes. Put one of the petri dishes into a 9cm dish with cold water (the water should not overflow into the small petri dish), so that the medium at the bottom of the dish cools down and solidifies first, while the medium at the top remains in a soluble state. Carefully bury the prepared stigma and other gynoecium tissues in the sol, and sprinkle a little pollen on the sol as it cools. In another petri dish sprinkle unevenly wash a little pollen of the leading flower.
Place the above (2, 3, 4, 5, 6) pollen cultures in a 25℃ thermostat.
2. Observation of nutritional conditions: after 10 M in, the cultures in each small ring were removed and observed under the microscope to compare the pollen germination.
3. Observation of collective effect: after 1 h, petri dishes with uneven distribution of pollen were taken and pollen germination was compared between dense and sparse pollen areas.
4. Observation of orientation: after 1h, take out the petri dish buried with pistil tissue and observe the growth of pollen tube around the pistil tissue.
III. RESULTS
1. Select the representative pollen germination field of view under different nutritional conditions to observe the results and draw the diagrams, and compare the germination situation.
2. Select three fields of view each of dense and sparse pollen in Petri dishes to calculate the percentage of pollen germination.
3. Observe and graph the anisotropy of pollen tube growth of the leading flower in a petri dish with buried pistil tissue.