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Nitrate Production in Two Forest Soils and Nitrate Reduction in Pine
Author(s) -
Theobald W. F.,
Smith W. H.
Publication year - 1974
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1974.03615995003800040037x
Subject(s) - slash pine , nitrate , nitrate reductase , ammonium , germination , chemistry , nitrification , soil water , radicle , substrate (aquarium) , enzyme assay , nutrient , botany , agronomy , pinus <genus> , biology , nitrogen , enzyme , ecology , biochemistry , organic chemistry
Acid forest soils showed low capacities for nitrification even when substrate NH 4 ‐N was increased. Under forest soil pH conditions and NO 3 levels typical of the lower coastal plain, pine roots ( Pinus spp.) possessed low nitrate reductase (NR) activities. An in vivo assay showed NR activity in slash pine roots ( P. elliottii Englm. var. ‘elliottii’). Activity depended on NO 3 level and pH of nutrient solution. Highest activity was with 100 ppm NO 3 ‐N at pH 6. Ammonium‐grown seedlings possessed low levels of activity even at pH 4, indicating constitutive nature or early induction of the enzymes. Radicles of seeds aseptically germinated actively reduced NO 3 , indicating activity within the root tissues. Daily patterns of fluctuation in NR activity similar to the pattern for photosynhesis were observed. In vitro assay attempts were unsuccessful, due apparently to the presence of inhibitors.