Nitrogen uptake and utilisation as a competition factor between invasive Duchesnea indica and native Fragaria vesca

作者：Littschwager Johanna^*; Lauerer Marianne; Blagodatskaya Evgenia; Kuzyakov Yakov

来源：Plant and Soil, 2010, 331(1-2): 105-114.

DOI：10.1007/s11104-009-0236-2

• N utilisation
• Duchesnea indica
• Fragaria vesca
• (15)N uptake
• Competition strategies
• Invasive species

The Indian mock strawberry [Duchesnea indica (Andrews) Focke] is an invasive plant in several regions of central Europe and Germany. In order to explore its competitive ability, we compared it with the native woodland strawberry (Fragaria vesca L.) by growing it alone as well as in intra- or inter-specific competition in a pot experiment under greenhouse conditions. Nutrient solution was added several times at two nitrogen (N) levels. One addition involved (15)N labelling to determine whether the competition of both plant species depends on their ability to acquire N from soil. Duchesnea had a higher biomass production than Fragaria when grown in nutrient-rich soil, both in competition and as a solitary plant. Under N-poor conditions, root interference could change this superiority due to limited soil space. After 65 days of growth, total plant dry weight, total N content and (15)N content in the plant tissues were determined. The results show that the predominance of Duchesnea in biomass production was confirmed at high, but not at low N availability. The assimilate partitioning strategy of Duchesnea differs from that of Fragaria: the former generally had a higher shoot-to-root ratio. The N content in shoots and roots was affected only by N addition but not by competition or species. Duchesnea allocated more N to the leaves, Fragaria to the roots. The amount of (15)N taken up was nearly equal for both species. In relation to root biomass, Duchesnea had a higher specific uptake rate at low N addition because of the higher root biomass in Fragaria. The roots of Fragaria and Duchesnea did not affect each other when grown together. We conclude that the invasive potential of Duchesnea is only poorly related to the N uptake rate or to better root competition for N. In N-rich environments, however, Duchesnea is highly competitive because of the preferred investment in shoot biomass. Therefore, environments with increased N deposition, i.e. from anthropogenic sources, could promote the invasive potential of Duchesnea.

• 出版日期2010-6