Table 3.

PSI and PSII electron transport activity in isolated mesophyll (M) and bundle sheath (BS) thylakoids of Echinochloa crus-galli, Digitaria sanguinalis, and Zea mays chloroplasts from control plants (200 µmol photons m⁻² s⁻¹) and then transferred to high light (HL) for 1 h (1600 μmol photons m⁻² s⁻¹)

Light intensity (µmol photons m−2 s−1)	PSII activity (µmol DCPIP mg−1 Chl h−1)				PSI activity (µmol O2 mg−1 Chl h−1)
	200		1600		200		1600
	M	BS	M	BS	M	BS	M	BS
Zea mays	89 ± 1	15 ± 2	47 ± 1	10 ± 1	296 ± 1	1020 ± 9	156 ± 2	565 ± 3
Digitaria sanguinalis	40 ± 1	32 ± 3	37 ± 1	25 ± 9	284 ± 6	657 ± 1	176 ± 1	407 ± 4
Echinochloa crus-galli	57 ± 2	30 ± 7	49 ± 4	22 ± 9	189 ± 2	671 ± 2	156 ± 9	429 ± 5

Details are given in Materials and methods. The electron transport activities of PSI were measured polarographically at 25 °C. Chloroplast equivalents of 30 µg mL⁻¹ (M) and 10 µg mL⁻¹ (BS) of chlorophyll were used for PSI measurements, chloroplast equivalents of 20 µg mL⁻¹ of chlorophyll were used for PSII measurements. DCPIP was 0.1 mM. Values are mean ± SD of three independent experiments for PSI, means of 4–5 separate experiments ± SE (three replicates each) for PSII