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Arfin Khan, Mohammed Abu Sayed ; Kreyling, Jürgen ; Beierkuhnlein, Carl ; Jentsch, Anke:
Ecotype-specific improvement of nitrogen status in European grasses after drought combined with rewetting.
In: Acta Oecologica.
Bd. 77
(2016)
.
- S. 118-127.
ISSN 1873-6238
DOI: https://doi.org/10.1016/j.actao.2016.10.004
Abstract
Drought stress and associated low soil moisture can decrease N status of forage plants by reducing nitrogen(N) uptake. Conversely, rainfall and associated favorable soil moisture can improve plant N status.Yet, it is unclear to which degree drought combined with rewetting can buffer negative effects of droughton N status of forage plants and their populations. Here, we compared shoot N status (N concentration,total N uptake and C/N ratio) of four temperate grass species. Particularly, we investigated ecotypes(populations) grown from seeds from four to six European provenances/species after a drought treatmentcombined with rewetting (10 day harvest delay) versus continuously watered conditions forcontrol.The experimental combination of drought and rewetting significantly increased shoot N concentration(þ96%), N uptake (þ31%); and decreased C/N ratio (46%), biomass production (29%) and C concentration(1.4%) compared to control. Shoot N status was found to be different between target grassspecies and also within their populations under drought combined with rewetting treatment. Presumablydrought-adapted populations did not perform better than populations from moist sites indicating noevidence of local adaptation.The drought combined with rewetting event could buffer the negative effects of drought. Shoot Nstatus of grasses after drought and rewetting even exceeded control plants. This surprising finding canpotentially be explained by higher N uptake, lack of growth dilution effects or delayed plant maturation.Furthermore, within-species shoot N status responses to drought combined with rewetting event wereecotype-specific, hinting at diverse responses of different population. For rangeland management, werecommend that if a drought event occurs during the growing season, harvesting should be delayedbeyond a following rain event.