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Nitrate and reduced‐N concentrations in the xylem sap of Stellaria media, Xanthium strumarium and six legume species
Author(s) -
ANDREWS M.
Publication year - 1986
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/1365-3040.ep11616359
Subject(s) - phaseolus , cajanus , xylem , nitrate reductase , nitrate , sativum , botany , lupinus , biology , pisum , legume , shoot , stellaria media , trifolium repens , agronomy , horticulture , chemistry , weed , ecology
At an applied nitrate concentration of 1 mol m −3 , the proportion of xylem sap nitrogen as nitrate was < 15% for Cajanus cajan, Lupinus albus and Trifolium repens , 33% for Pisum sativum and within the range 57–62% for Glycine max, Phaseolus vulgar is, Stellaria media and Xanthium strumarium. At an applied nitrate concentration of 10 mol m∼ 3 the value had increased to 66% for T. repens while at 20 mol m −3 nitrate values had increased to 46, 51 and 49% for C. cajan, L. albus and Pisum sativum , respectively, and 89% and 85% for 5. media and X. strumarium , respectively. Glycine max and Phaseolus vulgaris differed from the other species in that the proportion of their xylem sap nitrogen as nitrate remained constant (∼ 60%) as applied nitrate concentration increased from 1 to 20 mol m −3 . The proportion of total plant nitrate reductase activity in the shoot of C. cajan, S. media and X. strumarium increased as applied nitrate concentration increased from 1 to 20 mol m −3 . Values at the lower and upper concentrations were, respectively, 26 and 72% for C. cajan. 48 and 80% for X. strumarium and 68 and 87% for S. media. The partitioning of nitrate assimilation between root and shoot in these species is discussed.