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Remobilized old-leaf nitrogen predominates for spring growth in two temperate grasses
- Source :
- New Phytologist. 152:283-290
- Publication Year :
- 2001
- Publisher :
- Wiley, 2001.
-
Abstract
- 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 15N-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.
Details
- ISSN :
- 0028646X
- Volume :
- 152
- Database :
- OpenAIRE
- Journal :
- New Phytologist
- Accession number :
- edsair.doi...........81383683439bff74357932fed0572513