Table III.

Urease specific activity^a in the protein solutions with molecular mass ≥10 kD of Ni-S and Ni-D foliage from young pecan seedling trees

Sample	Activityb	Specific Activity (X ± sd)b
	unit/g fresh leaflet	unit/mg protein
Ni-D	23.64 ± 5.08b	5.91 ± 1.27b
Ni-S	121.56 ± 13.92a	30.39 ± 3.48a

^aEnzyme activity was expressed by mean (±sd).

^bMeans (±sd) followed by the same letter are not significantly different (t test; P ≤ 0.05).