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A novel interaction of magnesium translocation with the supply of phosphorus to roots of grapevine ( Vitis vinifera L.) *
Author(s) -
SKINNER P. W.,
MATTHEWS M. A.
Publication year - 1990
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/j.1365-3040.1990.tb01098.x
Subject(s) - xylem , photosynthesis , vitis vinifera , phosphorus , exudate , shoot , chemistry , horticulture , nutrient , transpiration , chromosomal translocation , magnesium , agronomy , botany , biology , biochemistry , organic chemistry , gene
Abstract. The role of phosphorus (P) in leaf magnesium (Mg) concentrations and photosynthesis was investigated in field and glasshouse experiments with grapevine ( Vitis vinifera L., cvs. Chenin blane. Chardonnay, and Carignane). In the field, leaves of vines growing on soil with low available P exhibited symptoms of Mg deficiency and had low P and Mg concentrations. The rate of photosynthesis for leaves of untreated control vines was approximately 0.7 nmol CO 2 cm 2 s 1 . When P fertilizer was applied to the soil, Mg deficiency symptoms were eliminated, and leaf P and Mg concentrations increased to above critical levels. When Mg was applied as a foliar spray, leaf Mg increased to above critical levels, but leaf P did not change significantly. In both experiments, the rate of photosynthesis increased to greater than 1.0 nmol CO 2 cm 2 s 1 after nutrient applications. Thus, under low soil P conditions, leaf photosynthesis was limited by leaf Mg concentrations. In glasshouse experiments in which vines were grown with and without P for three seasons, Mg accumulated in large roots of ‐ P vines to approximately twice the concentration found in roots of + P vines. Analysis of the xylem exudate from detopped plants showed that Mg concentration in xylem sap of + P vines was twice as great as that in ‐ P vines. When P was supplied to ‐ P vines, the concentration of Mg increased to the concentration of + P vines within 2 days. The results show that the translocation of Mg from roots to shoots of grapevine is dependent upon P supply to the roots and suggest that Mg translocation is more sensitive than uptake to P supply.