Table III.

COX activity in whole-tissue extracts and isolated mitochondria from soybean roots of various ages (4, 7, and 17 d old)

Source	COX Activity
	4 d	7 d	17 d
Whole tissue	μmol O2 min−1 g−1 dry mass
	26  ± 3	19  ± 1	11  ± 3
Purified mitochondria	μmol O2 min−1 mg−1 protein
	1.25  ± 0.08	0.80  ± 0.05	0.50  ± 0.04
Tissue mitochondrial  content	mg mitochondrial protein g−1 dry mass
	22  ± 2	24  ± 2	22  ± 5

Numbers are means ± se (n = 4).