Equipment
Method
- Sucrose solution 2moldm-3
- Mineral salt culture medium
- Microscope
- Plants in flower
- Five Petri Dishes
- Filter paper
- Distilled water
- Measuring cylinders
- Stop clock
- Clean cavity slides
- Mounting needles
Method
- Carry out research into what concentrations of sucrose might be a suitable range to test in this experiment. I used 0.0 , 0.2, 0.4, 0.8, 1.6 Sucrose solution moldm^-3
- Make up the solutions of sucrose and add mineral salt culture medium in a 1:1 ratio
- Label 5 petri dishes 0, 0.2, 0.4, 0.8 and 1.6 and add a filter paper which has been damped with their respective concentrations. This is to ensure the slides don’t dry out between observations, the petri dish acting as a humid chamber
- Label one slide per sucrose concentration and pipette a few drops of the respective concentration solutions into the cavity of the slides.
- Collect a flower that has mature anthers and is shedding pollen and rub the mounted needle over the anther allowing pollen to fall onto the cavity of the microscope slide. Use the same species of plant for each slide
- Every few hours, check back on the pollen and record the growth of the pollen tubes under the x100 magnification, return the slide to the petri dish after every observation
Analysis
The results show that the optimum concentration for pollen tube growth was 0.4 moldm^-3, concentrations around this optimum all resulted in a lower percentage of pollen tubes growing on the slide. This is due to the movement of water by osmosis into the pollen tube and out of the pollen tube at the different concentrations. The 1963 paper produced by J.L Brewbaker and B.H Kwack(1.) outlined the importance of calcium ions within pollen tube germination and growth. Before they made this groundbreaking discovery only Boron, as a Borate, was shown to have any effect on increasing the speed at which the pollen tube grows at. Ions such as Na+, Mg2+, and K+ were all shown to have no increased effect unless Ca2+ also got involved in the experiment. This had major repercussions within the Scientific community in speeding up the rate at which the pollen tubes grow at. The world would never look at pollen tubes in the same way again.
1. Brewbaker, James L., and Beyoung H. Kwack. “The Essential Role of Calcium Ion in Pollen Germination and Pollen Tube Growth.” American Journal of Botany, vol. 50, no. 9, 1963, pp. 859–865., www.jstor.org/stable/2439772.
The results show that the optimum concentration for pollen tube growth was 0.4 moldm^-3, concentrations around this optimum all resulted in a lower percentage of pollen tubes growing on the slide. This is due to the movement of water by osmosis into the pollen tube and out of the pollen tube at the different concentrations. The 1963 paper produced by J.L Brewbaker and B.H Kwack(1.) outlined the importance of calcium ions within pollen tube germination and growth. Before they made this groundbreaking discovery only Boron, as a Borate, was shown to have any effect on increasing the speed at which the pollen tube grows at. Ions such as Na+, Mg2+, and K+ were all shown to have no increased effect unless Ca2+ also got involved in the experiment. This had major repercussions within the Scientific community in speeding up the rate at which the pollen tubes grow at. The world would never look at pollen tubes in the same way again.
1. Brewbaker, James L., and Beyoung H. Kwack. “The Essential Role of Calcium Ion in Pollen Germination and Pollen Tube Growth.” American Journal of Botany, vol. 50, no. 9, 1963, pp. 859–865., www.jstor.org/stable/2439772.