Soil characteristics and nitrogen resorption in Stipa krylovii native to northern China

Abstract

Nitrogen (N) resorption from senescing tissues enables plants to conserve and reuse this important nutrient. As such, it is expected that plant species adapted to infertile soils could have a higher N-resorption efficiency (percentage reduction of nitrogen between green and senescing tissues) and/or higher N-resorption proficiency (absolute reduction of nitrogen in senescing tissues) than those adapted to fertile soils. To test this hypothesis, we investigated the relationships among soil characteristics (total N, nitrate-N, ammonium-N, pH and moisture) and N resorption in Stipa krylovii Roshev., a species occurred widely in natural grasslands of northern China. N contents in green and senescing tissues were 6.7 ± 0.1 and 3.3 ± 0.1 mg g )1 , respectively. The mean value of N-resorption efficiency was found to be 72.1%. The N-resorption efficiency in S. krylovii was independent of soil characteristics. The N-resorption proficiency in S. krylovii was dependent on soil nitrate-and ammonium-N, but it was relatively independent of soil total N. The N-resorption proficiency was negatively correlated with soil pH and moisture. There was a positive correlation between N concentration in green tissues and resorption efficiency. However, N-resorption efficiency was not correlated significantly with N concentration in senescing tissues. These results indicate that the intraspecific variation in N resorption of Stipa krylovii Roshev. is associated with soil regimes and that higher N resorption on N-poor soils is an adaptive strategy for S. krylovii to maximize N use under conditions of limited N supply.

Résorption foliaire chez Quercus petraea subsp. iberica et Arbutus andrachne le long d’un gradient altitudinal

“…Huang et al (2007) found that N concentration in senesced leaves was lower in species with longer leaf lifespan. High resorption proficiency implies low concentrations because a low N concentration in senesced parts is the evidence of high proficiency, and vice versa (Yuan et al, 2005a). Deciduous species was more proficient because low N concentrations were found in senescent leaves.…”

“…Some researchers reported a positive correlation between NRE and green-leaf nutrient concentrations (del Arco et al, 1991;Escudero et al, 1992), while other researchers stated that such a relationship was not found between NRE and green-leaf nutrient concentrations (Huang et al, 2007;Niinemets and Tamm, 2005;Yuan et al, 2005a). Ratnam et al (2008) stated that both NRE and PRE decreased as nutrient concentrations in green leaves increased.…”

“…Killingbeck (1996) emphasized that resorption proficiency (the concentration of a nutrient in senesced leaves) over resorption efficiency is not subject to temporal variation in nutrient concentration in green leaves or the timing of sampling. Proficiency is simply the amount of a nutrient that remains in fully senesced leaves (Yuan et al, 2005a). Two sympatric species along an elevational gradient were selected for this study.…”

Nitrogen and Water Utilization Efficiency of Barley Subjected To Desiccated Conditions in Moderately Salt-Affected Soil

“…Li et al (2003) found that desiccated conditions and a high amount of N applied could result in a low N efficiency. Furthermore, water stress could negative affect the movement of nutrient in the soil, resulting in a decrease in its absorb by the roots of plant Yuan et al (2005).…”

Nutrientes Foliares De Espécies Arbóreas Na Mata Atlântica: Efeito Do Tamanho Do Fragmento

“…M. 322 A alta concentração de N encontrada nas folhas das espécies estudadas quando comparada com outras florestas tropicais, evidencia o potencial de ciclagem interna deste elemento pelas plantas (SILVA, 2009). YUAN et al (2005), avaliando a retranslocação de N em floresta seca do semiárido da China, verificaram que folhas com altas concentrações de N foram as que apresentaram mecanismo eficiente de retranslocação.…”