Tougher Plants Beating Stress

Part 1: Stress
1. The major stresses that agricultural plants face are drought stress, cold stress, heat stress, flooding stress, mineral deficiency stress, salinity stress, and aluminum toxicity stress.

Part 2: Glycine Betaine
2a. Wild type means it is the phenotype of the typical form of a species as it occurs in nature. 2b. L1 is different from the wild type because it is a strain of the wild type after a mutation occurred and changed some of its phenotype characteristics.

3. Glycine betaine counteracts the effects of salt and temperature stress. It is a substance that is synthesized and taken from the environment by the cells for protection against stress for the leaves, flowers, and fruits in cold exposed plants. It moderates stress in plants.

Part 3: Photosynthesis
4. The x axis is measuring the days after the cold treatment.

5. The y axis is measuring the percent of ion leakage.

6. WT on the graph means wild type.

7. L1 and L5 are independent transgenic plants.

8. The photosynthesis process that is most affected by ion leakage is whether the ATP synthase will function.

9. Two trends I can observe in the graph are that the wild type has the greatest percentage of ion leakage 7 days after the cold treatment while both L1 and L5 had varying percents of ion leakage throughout the 7 days but at the end they had the same amount of ion leakage.

Part 4: Heat Tolerance
10. The x axis is measuring the different temperatures of the treatments the plants were exposed to.

11. The y axis is measuring the changes in the oxygen producing activity of the PSII determined by the thylakoid membranes.

12. The two types of plants that are being studied in this experiment are the wild type and a genetically modified type.

13. The process in photosynthesis that produces oxygen is photolysis.

14. Two trends that I can observe in the graph are both types of plants had about the same oxygen producing activity from 25 degrees Celsius to 35 degrees Celsius. However, they split and the wild type of plant drastically decreased while the genetically modified type stayed constant then only decreased a little in its oxygen producing ability.

Part 5: Photosysytem II
15. The red circle part of the molecule goes through the thylakoid membrane.

16. This explains why increased temperatures decrease photosystem II activity because the chlorophyll breaks down.

Part 6: Salt
17. The x axis is measuring the amount of betaine that was used to incubate PS2 particles.

18. The y axis is measuring the percent of the amount of protein that remain associated with the particle.

19. Lines a, b, and c refer to the dislocation of three extrinsic proteins
from PS II particles.

20. Two trends I can observe in the graph are that the 33kDa protein started with the highest percentage of protein that remained associated and the other two proteins started at 0 percent and ended up with 100 percent of the amount of potein that remained associated.

21. The protein subunit that is most stable and likely to be in the membrane is protein c.

22. The protein subunit that is least stable is protein a, and it is most likely to be a peripheral membrane protein.

23. Glycine betaine protects photosystem II activity because it helps retain the water and keeps the amount of protein high in order to make ATP.