Reciprocal grafting separates the roles of the root and shoot in zinc hyperaccumulation in Thlaspi caerulescens.
* The extreme phenotype of zinc (Zn) hyperaccumulation, which is found in several Brassicaceae species, is determined by mechanisms that promote elevated Zn tolerance and high Zn accumulation in shoots. * We used reciprocal grafting between a Zn hyperaccumulator, Thlaspi caerulescens, and a Zn nonaccumulator, Thlaspi perfoliatum, to determine the relative importance of roots and shoots in Zn hyperaccumulation and hypertolerance. * Leaves from plants with a T. perfoliatum rootstock and a T. caerulescens shoot scion did not hyperaccumulate Zn, whereas plants with a T. caerulescens rootstock and a T. perfoliatum shoot scion did hyperaccumulate Zn. However, although leaves from plants with a T. caerulescens rootstock and a T. perfoliatum shoot scion hyperaccumulated Zn, at high Zn loads these leaves showed significant symptoms of Zn toxicity, unlike leaves of self grafted T. caerulescens. * Hyperaccumulation of Zn in leaves of the hyperaccumulator T. caerulescens is pri-marily dictated by root processes. Further, the mechanisms controlling Zn hypertolerance in the hyperaccumulator T. caerulescens are driven primarily by shoot processes.
Guimarães
Marcelo de A
MA
Gustin
Jeffery L
JL
Salt
David E
DE
D000222:Adaptation, Physiological / Q000502:physiology*; D018515:Plant Leaves / Q000378:metabolism; D018517:Plant Roots / Q000378:metabolism; D018520:Plant Shoots / Q000378:metabolism; D018514:Plant Structures / Q000378:metabolism*; D031227:Thlaspi / Q000378:metabolism*; D015032:Zinc / Q000378:metabolism*
D015032:Zinc