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