XVI International Botanical Congess
Growth of leaves and fruits of plants in drying soil can be influenced both by chemical regulators and by hydraulic influences. There is now good evidence that chemical regulators provide the shoots of the plant with a 'measure' of the availability of water in the soil. While hormones may play a central role in the signalling process, it is now clear that signalling can involve more than modifications in the flux of compounds moving between roots and shoots. This paper will emphasise the importance of being able to define the hormone balance and the balance of inorganic ions in the compartments immediately adjacent to sites of regulation within the leaf.