First published in 1987 this book looks at root development and functions. Besides affecting the development of roots directly, the physical environment also influences the organisms associated with roots and thus affects their function. The papers presented in this volume pay equal attention to root development and root function in relation to the whole range of environmental factors including temperature, light, water, aeration, gravity and the mechanical strength of the soil. Consideration is also given to the effects of some of these factors on mycorrhizae and nitrogen-fixing bacteria. The final chapter reviews some of the main themes raised in the volume and indicates the way that research at the cellular and tissue levels may progress in the future.