abstract- the effects of iron (fe) and zinc (zn) treatments on the growth and nutrient composition of chickpea were studied in a greenhouse experiment arranged in a completely randomized design. while the application of fe decreased mean shoot dry weight of chickpea, that of zn had no significant effect on chickpea shoot dry weight. increasing fe levels drastically decreased mn concentration an...

We assessed the effects of nutrient supply and dietary bulk, both increasing with hay intake, on O2 uptake and nutrient net fluxes across the portal-(PDV) and mesenteric- (MDV) drained viscera, and the rumen in adult ewes. Four ewes, fitted with a ruminal cannula, with catheters in the mesenteric artery, the portal, mesenteric and right ruminal veins, and with a blood flow probe around the righ...

the effect of tillage (conventional and zero tillage), crop establishment (raised-bed and flat-bed), and weed management practices (herbicide alone and integrated approach) was studied on productivity, profitability, nutrient uptake and physico-chemical properties of soil in soybean–wheat cropping system, at new delhi during 2010–2012. sixteen treatment combinations consisting of four tillage a...

We only have a limited understanding of the nutrient uptake physiology of individual roots as they age. Despite this shortcoming, the importance of nutrient uptake processes to our understanding of plant nutrition and nutrient cycling cannot be underestimated. In this study, we used a N depletion method that allowed for the measurement of nitrate-N uptake rates on intact, individual, fine roots...

A model for nutrient uptake rate (V) in phytoplankton is derived: V = n A v S / ( l + h A v S ) where n is cellular number of uptake sites, A is area of the uptake site, h is time required for handling one nutrient ion, vis the mass transfer coefficient, and S i s substrate concentration. The model is based on 2 time requirements necessary for active uptake of nutrients: (i) time required for r...

Plants modify nutrient availability by releasing chemicals in the rhizosphere. This change in availability induced by roots (bioavailability) is known to improve nutrient uptake by individual plants releasing such compounds. Can this bioavailability alter plant competition for nutrients and under what conditions? To address these questions, we have developed a model of nutrient competition betw...

25 We have a limited understanding of the consequences of variations in microbial biodiversity on ocean ecosystem functioning and global biogeochemical cycles. A core process is macronutrient uptake by microorganisms, as the uptake of nutrients controls ocean CO2 fixation rates in many regions. Here, we ask if variations in ocean phytoplankton biodiversity lead to novel functional relationships...

Nutrient uptake by roots often involves substrate-dependent regulated nutrient transporters. For robust uptake, the system requires a regulatory circuit within cells and a collective, coordinated behaviour across the tissue. A paradigm for such systems is boron uptake, known for its directional transport and homeostasis, as boron is essential for plant growth but toxic at high concentrations. I...

We developed a stoichiometrically explicit computer model to examine how heterotrophic uptake of nutrients and microbial mineralization occurring during the decay of leaves in streams may be important in modifying nutrient concentrations. The simulations showed that microbial uptake can substantially decrease stream nutrient concentrations during the initial phases of decomposition, while miner...