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Remobilized old‐leaf nitrogen predominates for spring growth in two temperate grasses
Author(s) -
Bausenwein Ursula,
Millard Peter,
Raven John A.
Publication year - 2001
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1046/j.0028-646x.2001.00262.x
Subject(s) - overwintering , perennial plant , biology , agronomy , temperate climate , festuca rubra , nutrient , biomass (ecology) , botany , ecology
Summary• The importance of N derived from internal remobilization and root uptake to growth in spring is reported here for the perennial grasses Festuca rubra and Agrostis capillaris derived from seminatural grasslands in Scotland, UK. • Plants grown in sand culture, received 15 N‐enriched nutrient solution during the first year of growth and nutrient solution with N at natural abundance during the subsequent spring and summer when destructive harvests were taken. • Labelled N was recovered in new growth of overwintering tillers and new tillers. Remobilized N contributed 70% and 82% for F. rubra and A. capillaris , respectively, to the total N in new above‐ground growth in early spring, declining to 34% and 45%, respectively, by mid June. Species showed similar patterns of remobilization on a new growth biomass basis. The root system did not remobilize N to support new above‐ground growth. Labelled N was derived from senescing leaves present on overwintering tillers. Net balances of labelled N suggest that N was translocated between tillers; reproductive tillers acted as sinks, vegetative tillers as the source of N. • Initial growth in spring is largely independent of N uptake from the soil, provided that overwintering leaves are present on the plants.