title: Common and specific responses to availability of mineral nutrients and water.
abstract: Changes in resource (mineral nutrients and water) availability, due to their heterogeneous distribution in space and time, affect plant development. Plants need to sense these changes to optimize growth and biomass allocation by integrating root and shoot growth. Since a limited supply of water or nutrients can elicit similar physiological responses (the relative activation of root growth at the expense of shoot growth), similar underlying mechanisms may affect perception and acquisition of either nutrients or water. This review compares root and shoot responses to availability of different macronutrients and water. Attention is given to the roles of root-to-shoot signalling and shoot-to-root signalling, with regard to coordinating changes in root and shoot growth and development. Involvement of plant hormones in regulating physiological responses such as stomatal and hydraulic conductance is revealed by measuring the effects of resource availability on phytohormone concentrations in roots and shoots, and their flow between roots and shoots in xylem and phloem saps. More specific evidence can be obtained by measuring the physiological responses of genotypes with altered hormone responses or concentrations. We discuss the similarity and diversity of changes in shoot growth, allocation to root growth, and root architecture under changes in water, nitrate, and phosphorus availability, and the possible involvement of abscisic acid, indole-acetic acid, and cytokinin in their regulation. A better understanding of these mechanisms may contribute to better crop management for efficient use of these resources and to selecting crops for improved performance under suboptimal soil conditions.
authors.affiliation: Institute of Biology, Ufa Science Centre, Russian Academy of Sciences, pr. Oktyabrya 69, 450054 Ufa, Russia guzel@anrb.ru.
authors.forename: Guzel R
authors.initials: GR
authors.lastname: Kudoyarova
authors.affiliation: The Lancaster Environment Centre, Lancaster University, LA1 4YQ Lancaster, UK.
authors.forename: Ian C
authors.initials: IC
authors.lastname: Dodd
authors.affiliation: Institute of Biology, Ufa Science Centre, Russian Academy of Sciences, pr. Oktyabrya 69, 450054 Ufa, Russia.
authors.forename: Dmitry S
authors.initials: DS
authors.lastname: Veselov
authors.affiliation: The Lancaster Environment Centre, Lancaster University, LA1 4YQ Lancaster, UK.
authors.forename: Shane A
authors.initials: SA
authors.lastname: Rothwell
authors.affiliation: Bashkir State University, Zaki-Validi Street, 32, 450074 Ufa, Russia.
authors.forename: Stanislav Yu
authors.initials: SY
authors.lastname: Veselov
mesh_terms: D004777:Environment; D008903:Minerals / Q000378:metabolism*; D010937:Plant Growth Regulators / Q000378:metabolism; D018517:Plant Roots / Q000378:metabolism; D015398:Signal Transduction; D014867:Water / Q000378:metabolism*
chemical_list: D008903:Minerals; D010937:Plant Growth Regulators; D014867:Water
keywords: Mineral nutrients; abscisic acid; auxin; cytokinins; growth; intracellular and long-distance signalling; root architecture.; sugars; water deficit