Nutrient Uptake and Productivity Pattern in Wheat Under Populus Deltoides Based Agrisilviculture System

Mechanistic nutrient uptake models can help gain a quantitative understanding of nutrient uptake by plants under weed-competing conditions. The objectives of this study were to check the applicability of the soil supply and nutrient demand (SSAND) model to predict N, P and K uptake by hybrid poplar (Populus deltoides × Populus × petrowskyana var. Walker) grown with and without competition with dandelion (Taraxacum officinale) and quackgrass (Elymus repens) in a controlled environment, and to determine if incorporating N mineralization into the model would improve N uptake predictions. Simulation results showed that N uptake was underestimated for hybrid poplar by 58 to 73%, depending upon soil type and weed treatment. Incorporation of N mineralization as a model input improved the hybrid poplar N uptake predictions by 24 and 67% in the pasture and alfalfa soil, respectively, when grown without weeds. The SSAND model underestimated P uptake by 84 to 89% and overestimated K uptake by 28 to 59% for hybrid poplar depending upon the soil type and weed treatment. Results from this study illustrate that modeling competition between two species in a controlled environment study is a complex process and that further work is required to understand the underlying processes controlling nutrient supply and uptake in these systems. Key words: Nutrient uptake modeling, SSAND model, hybrid poplar, weeds, sensitivity analysis

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Effect of Some Natural Mineral Waters in Nutrient Uptake by Caco-2 Cells

International Journal for Vitamin and Nutrition Research ◽

10.1024/0300-9831/a000013 ◽

2010 ◽

Vol 80 (2) ◽

pp. 131-143 ◽

Cited By ~ 3

Author(s):

Pedro Gonçalves ◽

João R. Araújo ◽

Fátima Martel

Keyword(s):

Nutrient Uptake ◽

Mineral Waters ◽

Distilled Water ◽

Natural Mineral ◽

Minute Exposure

We studied the effect of some mineral waters and some of their constituents on the apical uptake of 14C-butyrate (14C-BT) and 3H-O-methyl-D-glucose (3H-OMG) by Caco-2 cells. Uptake of 14C-BT increased after a 20-minute exposure to 1 % (v/v) distilled water, and, compared to distilled water, it was decreased by Pedras Salgadas® 1 % (v/v) and Melgaço® 5 % (v/v), and increased by Vidago® 5 % (v/v). Moreover, it increased after a 48-hour exposure to Vidago® or Melgaço® waters (5 % (v/v)). Also, uptake of 14C-BT was reduced after a 20-minute exposure to MgCl2, MgSO4, or CaCl2. Uptake of 3H-OMG was reduced after a 20-minute exposure to Melgaço® water [1 % (v/v)], when compared to distilled water. Also, a 48-hour exposure to Pedras Salgadas® or Melgaço® water (5 % (v/v)) increased and decreased uptake, respectively. Finally, uptake of 3H-OMG decreased after a 20-minute exposure to MgSO4 or NaF. In conclusion, uptake of 14C-BT and 3H-OMG by Caco-2 cells is differently modulated by distinct mineral waters.

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