Implications of Global Climate Change for Impact of Weeds, Insects, and Plant Diseases

Nitrogen moves among plant organs in a variety of chemical combinations and over distances that reach all the plant extremities. Less progress has been made on the regulation of nitrogen (N) redistribution and the processes that govern the turnover of protein and release of soluble nitrogenous compounds into the transport system. Studies on the dynamics of N transport in a whole-plant context have dealt with short-term processes. The maximum N concentration of the reproductive organs is genetically determined by the nature of the organ components and varies with growing conditions. The parameters that represent management manipulation in the present context are those that control the supply of N to the substrate, and the initial state of the crop. Higher translocation rates affect biomass production at all levels of N supply but the effect works differently at low and high N supply levels.