Frost damage and winter nitrogen uptake by the grass Poa pratensis L.: consequences for vegetative versus reproductive growth
- 428 Downloads
Frost damage can decrease nitrogen uptake by grasses over winter, and it can also decrease biomass production over the following growing season. However, it is not clear to what extent reduced nitrogen uptake over winter decreases grass production, or whether is it merely a symptom of root damage. We examined the growth response of the grass Poa pratensis L. (Kentucky bluegrass) to variation in the timing of freezing and nitrogen availability over winter in London, Ontario, Canada. All tillers were transplanted into untreated soil in early spring, and at peak seed maturation, root, shoot, and reproductive biomass were measured. There was an interaction between freezing and increased winter nitrogen availability, whereby nitrogen addition increased tiller biomass under ambient temperatures, but decreased tiller biomass in combination with a late winter freeze. The nitrogen response of ambient temperature tillers occurred primarily via increased seed production, whereas for frozen tillers seed production was generally absent. Our results support the hypothesis that nitrogen uptake over winter can increase growing season productivity in P. pratensis, but also demonstrate that increased nitrogen availability increases tiller vulnerability to frost. These results have important implications for grass responses to the alteration of soil freezing dynamics with climate change.
KeywordsBiomass Freezing Grasses N uptake Seed production
This research was supported by a Natural Sciences and Engineering Research Council of Canada Discovery Grant to H.A.L.H. and an Ontario Graduate Scholarship to A.V.M.
- Bazzaz FA, Ackerly DD (1992) Reproductive allocation and reproductive effort in plants. In: Fenner M (ed) The ecology of regeneration in plant communities. CAB International, Wallington, pp 1–26Google Scholar
- Holman JD, Thill D (2005) Kentucky Bluegrass growth, development and seed production. University of Idaho College of Agricultural and Life Sciences Bulletin 843Google Scholar
- Lloyd DT, Soldat DJ, Stier JC (2011) Low-temperature nitrogen uptake and use of three cool-season turfgrasses under controlled environments. HortScience 46:1545–1549Google Scholar
- Meehl GA, Karl T, Easterling DR, Changnon S, Pielke R, Changnon D, Evans J, Groisman PY, Knutson TR, Kunkel KE, Mearns LO, Parmesan C, Pulwarty R, Root T, Sylves RT, Whetton P, Zwiers F (2000) An introduction to trends in extreme weather and climate events: observations, socioeconomic impacts, terrestrial ecological impacts, and model projections. B Am Meteorol Soc 81:413–416CrossRefGoogle Scholar
- Miltner ED, Stahnke GK, Johnston WJ, Golob CT (2004) Late fall and winter nitrogen fertilization of turfgrass in two pacific northwest climates. HortScience 39:1745–1749Google Scholar
- Noshiro M, Sakai A (1979) Freezing resistance of herbaceous plants. Low Temp Sci Ser B Biol Sci 37:11–18Google Scholar
- Vezina LP, Nadeau P (1991) The combined effects of rhizobial nodulation and nitrogen fertilization on growth and cold acclimation of alfalfa (Medicago sativa cv. Sranac). Ann Bot-London 68:359–363Google Scholar
- Webster DE, Edbon JS (2005) Effects of nitrogen and potassium fertilization on perennial ryegrass cold tolerance during deacclimation in late winter and early spring. HortScience 40:842–849Google Scholar
- Welterlen MS, Watschke TL (1985) Influence of drought stress and fall nitrogen fertilization on cold deacclimation and tissue components of perennial ryegrass turf. In: Lemaire R (ed) Proceedings of the 5th international turfgrass research conference. Institiute Nationale de la Recherche Agronomique, Avington, France, pp 831–840Google Scholar
- Zhang T, Barry RG, Knowles K, Ling F, Armstrong RL (2003) Distribution of seasonally and perennially frozen ground in the Northern Hemisphere. In: Phillips M (ed) Permafrost: Proceedings of the iighth international conference on permafrost. A.A Balkema, Zurich, pp 1289–1294Google Scholar