The regulation of zinc uptake in wheat plants

• Published in: Plant science (Limerick) Vol. 137; no. 1; pp. 1 - 12
• Main Authors: Santa-Marı́a, Guillermo E., Cogliatti, Daniel H.
• Format: Journal Article
• Language: English
• Published: Shannon Elsevier Ireland Ltd 23.09.1998; Elsevier Science
• Subjects: Absorption. Translocation of ions and substances. Permeability; Agronomy. Soil science and plant productions; Biological and medical sciences; Economic plant physiology; efflux; Fundamental and applied biological sciences. Psychology; growth; Heavy-metal; mineral metabolism; mortality; nutrient excess; nutrient solutions; nutrient uptake; Nutrition. Photosynthesis. Respiration. Metabolism; phytotoxicity; Roots; Triticum aestivum; Uptake; Wheat ( Triticum aestivum L.); Zinc; PTS, 8-hydroxi-1,3,6-pyrenetrisulphonic acid; Heavy-metal; NUR, net uptake rate; RGR, relative growth rate; Roots; DNP, 2,4- p-dinitrophenol; Wheat ( Triticum aestivum L.); RDW, root dry weight; Uptake; Zinc; Monocotyledones; Root; Flux; Bioavailability; Concentration; Soil pollution; Cereal crop; Heavy metal; Regulation(control); Absorption; Phytotoxicity; Gramineae; Angiospermae; Spermatophyta; Triticum aestivum
• ISSN: 0168-9452; 1873-2259
• DOI: 10.1016/S0168-9452(98)00112-5

The control of net zinc-uptake rate can be a critical factor for plant survival and growth in heavy metal polluted environments. Here we report the results of an study on the regulation of net Zn-uptake in wheat plants ( Triticum aestivum L.) grown in solution culture at supra optimum levels of Zn supply. As external Zn-concentration was increased, net Zn-uptake rate increased. The higher the external Zn-concentration the higher both Zn-influx and efflux, with Zn-efflux increasing more. However the relative increase in the outward flux of Zn was not enough to prevent the potential increase of Zn-concentration within plant tissues up to toxic levels. On the other hand, when the external Zn-concentration was changed to a higher or a lower level, the unidirectional Zn-influx changed almost instantaneously, while the net uptake rate of Zn changed slowly, towards the level exhibited by plants kept in the previous solution. These findings are consistent with the concept that regulation of Zn fluxes, at supra optimum levels of Zn supply, appear to be controlled primarily by Zn-efflux and not by short or long term regulation of Zn-influx.