Chapter 10 Nitrogen nutrition of plant and Nitrogen fertilizers
Nitrogen nutrition of plant and Nitrogen fertilizers Chapter 10
Plant nitrogen 1.1 Uptake of N 1. N is required by plants in large amounts Most plant material contains 2-4%N and 40%C. 2. N is usually the limiting nutrient in unfertilized systems 3. Most N is taken up from the soil in the form of nhat or no a small amount of NH can be absorbed through the leaves N2 can be used by legume plant via biological nitrogen fixation
I Plant nitrogen 1.1 Uptake of N 1. N is required by plants in large amounts. Most plant material contains 2-4% N and 40% C. 2. N is usually the limiting nutrient in unfertilized systems. 3. Most N is taken up from the soil in the form of NH4 + or NO3 - . A small amount of NH3 can be absorbed through the leaves. N2 can be used by legume plant via biological nitrogen fixation
Plant nitrogen Most plants grow best with a combination of NO3 and NH4 Some plants are specialists: e.g. use NH4 amino acids( e.g. mature forests, arctic tundra北极冻塬,rice) Some take up more Nhat than noa when both supplied together in equal amounts, but NO3 is prime form of N in soil solution Over-supply of Nhat can be toxic to plants
▪ Most plants grow best with a combination of NO3 - and NH4 + . ▪ Some plants are specialists: e.g. use NH4 + & amino acids (e.g. mature forests, arctic tundra北极冻塬, rice) ▪ Some take up more NH4 + than NO3 - when both supplied together in equal amounts, but NO3 - is prime form of N in soil solution ▪ Over-supply of NH4 + can be toxic to plants I Plant nitrogen
I Plant nitrogen Uptake of NH4 may be brought about by the facilitated diffusion(by the electropotential difference and cation selective channels). With Nhat nutrition recycling of ht back into the cytosol is restricted and the ht/pumped out of the cell and remain mainly outside and hence the pH is depressed
Uptake of NH4 + may be brought about by the facilitated diffusion (by the electropotential difference and cation selective channels). With NH4 + nutrition recycling of H+ back into the cytosol is restricted and the H+ /pumped out of the cell and remain mainly outside and hence the pH is depressed. I Plant nitrogen
Mechanism of uptake NO3 The uptake of NO3 is mainly a H#/NO 3 cotransport with the pumped out of the cell by the PM proton pump being recycled back into the cytosol Hence the nitrate uptake is associated with an pH increase in the outer medium
▪ The uptake of NO3 - is mainly a H+ / NO3 - cotransport with the pumped out of the cell by the PM proton pump being recycled back into the cytosol. ▪ Hence the nitrate uptake is associated with an pH increase in the outer medium. Mechanism of uptake NO3 -