Title: Changes in Urease Activity in Apple Trees as Related to Urea Applications
Abstract: Abstract Changes in urease (E.C.3.5.1.5.) were followed during the growth of 1‐year‐old MM 106 and 9‐year‐old Golden Delicious apple trees ( Malus pumila Rehd.). Urease was found in leaves, roots, and bark with actively growing tissues containing more activity than senescing tissues. The urease activity in the leaves declined steadily during leaf senescence but abscised leaves still contained about half of their initial urease activity. In the bark the urease activity changed only slightly. Urease activities in the leaves and bark of apple trees were always greater in those trees which had received an application of urea. In senescing apple leaves, urea induced a rapid increase in urease activity. The changes in total activity and specific activity of urease were parallel and suggests that urease was synthesized de novo . After urease activity reached a maximum, a rapid decline occurred. Urease was inhibited by low concentrations of ammonia and this decline may be due to product inhibition.
Publication Year: 1973
Publication Date: 1973-04-01
Language: en
Type: article
Indexed In: ['crossref']
Access and Citation
Cited By Count: 15
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