Explain why this treatment lowered the water potential of the maize seedling tissues.
After drying in air, mitochondria were isolated from the seedling tissues. The isolated mitochondria were then supplied with succinate, which is one of the intermediate compounds in the Krebs cycle, together with ADP and inorganic phosphate. The rate of oxygen uptake by the extracted mitochondria was measured. The results are shown in Fig. 4.1.
Describe the pattern shown in Fig. 4.1.
The mitochondria take up oxygen. Explain how this oxygen, plus the succinate, ADP and inorganic phosphate, are used by the mitochondria.
In a second experiment, mitochondrial membranes were observed to lose their normal arrangement when water potential was low. Suggest why membranes in cells lose their normal structure when the water potential is low.
Suggest how this could explain the results shown in Fig. 4.1.
When water potential in tissues is low, sorghum mitochondria are affected in much the same way as maize mitochondria. Describe two adaptations of sorghum plants that help prevent low water potentials developing in their tissues during drought conditions.