Award details

Dynamics of nutrient pools in plants and their relationship to crop growth, yield and quality

Reference	BBS/E/C/00091538
Principal Investigator / Supervisor	Dr Peter Barraclough
Co-Investigators / Co-Supervisors
Institution	Rothamsted Research
Department	Rothamsted Research Department
Funding type	Research
Value (£)	403,012
Status	Completed
Type	Institute Project
Start date	01/04/1997
End date	31/03/1999
Duration	24 months

Abstract

Plants must maintain nutrient concentrations within certain limits if growth, yield and quality are not to suffer. Current diagnostic procedures are based on total nutrient concentrations in plant dry matter which decline during growth and are affected by growing conditions. Nutrients in plants are present in three distinct functional pools - structural, storage and metabolic, and not all of them are involved in growth. Within a pool, a nutrient may be present in several chemical forms or fractions from simple inorganic ions to complex organic molecules. Plant and organ growth may be more closely related to the concentration of a specific nutrient fraction in a specific pool than to total nutrient concentration. Even if total nutrient concentration is the most important parameter for growth, a specific fraction or pool could serve as a useful tracker of total concentration if it was easier to measure, was specific and sensitive and maintained a constant relationship to the total nutrient. Surprisingly little is known about the distribution and dynamics of nutrient pools and fractions in crop plants as they develop and grow, and how concentrations are related to plant and organ growth and to grain yield. This will be studied in controlled environments and field experiments under wide- ranging nutritional and environmental conditions. Specific questions to be addressed include the benefits of expressing concentrations on a tissue water basis (especially important for K); the use of specific organs; and the use of storage pools for indicating optimal nutrient supply. The information gained should lead to better characterisation of plant nutrient requirements and to the development of physiologically-based diagnostic procedures. This will provide the basis for more effective nutrient management in the move towards precision farming and sustainable farming systems. In a field experiment on winter wheat (cv. Hereward) given different rates and timings of N, measure leaf N and chlorophyll concentrations for selected treatments and growth stages and relate to chlorophyll meter readings. This will establish the variability of chlorophyll/N ratios in field- grown wheat leaves. In a hydroponic experiment, determine how PO4-P concentrations change with leaf age and vary between leaves of the same physiological age on different stems. Winter wheat (cv. Mercia) will be grown at three external P concentrations to produce plants either deficient, adequately supplied or abundantly supplied with P. Collate experimental data from previous field experiments on relationships between plant K concentrations (in tissue water) and soil available K for a range of arable crops to compare ceiling concentrations to which different species accumulate K. GROWTH ROOM N: Investigate diurnal changes in stored leaf nitrate in young wheat plants. K: Determine the effect of K supply on growth (fwt, dwt and area) and cation concentrations (K, Ca, Mg - wet and dry) in all leaves and stems of young wheat plants. Are K concentrations maintained in expanding leaves in otherwise K- deficient plants? FIELD N: In a field experiment on winter wheat, different rates and timings of N will be used to determine the latest time during vegetative growth that N can be applied to affect yield. The experiment will also be used to investigate different approaches to the foliar diagnosis of crop N status (e.g. leaf %N and leaf nitrate, and leaf/canopy chlorophyll). K: Critical leaf and soil K for maximum grain yield of winter wheat will be determined on the continuing long-term K experiment at Rothamsted.

Summary

unavailable

Committee	Closed Committee - Agri-food (AF)
Research Topics	X – not assigned to a current Research Topic
Research Priority	X – Research Priority information not available
Research Initiative	X - not in an Initiative
Funding Scheme	X – not Funded via a specific Funding Scheme

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