Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - The cadmium-tolerant pea (Pisum sativum L.) mutant SGECd(t) is more sensitive to mercury
T2 - assessing plant water relations
AU - Belimov, Andrey A.
AU - Dodd, Ian C.
AU - Safronova, Vera I.
AU - Malkov, Nikita V.
AU - Davies, William J.
AU - Tikhonovich, Igor A.
PY - 2015/4
Y1 - 2015/4
N2 - Heavy metals have multiple effects on plant growth and physiology, including perturbation of plant water status. These effects were assessed by exposing the unique Cd-tolerant and Cd-accumulating pea (Pisum sativum L.) mutant SGECd(t) and its wild-type (WT) line SGE to either cadmium (1, 4 mu M CdCl2) or mercury (0.5, 1, 2 mu M HgCl2) in hydroponic culture for 12 days. When exposed to Cd, SGECd(t) accumulated more Cd in roots, xylem sap, and shoot, and had considerably more biomass than WT plants. WT plants lost circa 0.2 MPa turgor when grown in 4 mu M CdCl2, despite massive decreases in whole-plant transpiration rate and stomatal conductance. In contrast, root Hg accumulation was similar in both genotypes, but WT plants accumulated more Hg in leaves and had a higher stomatal conductance, and root and shoot biomass compared with SGECd(t). Shoot excision resulted in greater root-pressure induced xylem exudation of SGECd(t) in the absence of Cd or Hg and following Cd exposure, whereas the opposite response or no genotypic differences occurred following Hg exposure. Exposing plants that had not been treated with metal to 50 mu M CdCl2 for 1 h increased root xylem exudation of WT, whereas 50 mu M HgCl2 inhibited and eliminated genotypic differences in root xylem exudation, suggesting differences between WT and SGECd(t) plants in aquaporin function. Thus, root water transport might be involved in mechanisms of increased tolerance and accumulation of Cd in the SGECd(t) mutant. However, the lack of cross-tolerance to Cd and Hg stress in the mutant indicates metal-specific mechanisms related to plant adaptation.
AB - Heavy metals have multiple effects on plant growth and physiology, including perturbation of plant water status. These effects were assessed by exposing the unique Cd-tolerant and Cd-accumulating pea (Pisum sativum L.) mutant SGECd(t) and its wild-type (WT) line SGE to either cadmium (1, 4 mu M CdCl2) or mercury (0.5, 1, 2 mu M HgCl2) in hydroponic culture for 12 days. When exposed to Cd, SGECd(t) accumulated more Cd in roots, xylem sap, and shoot, and had considerably more biomass than WT plants. WT plants lost circa 0.2 MPa turgor when grown in 4 mu M CdCl2, despite massive decreases in whole-plant transpiration rate and stomatal conductance. In contrast, root Hg accumulation was similar in both genotypes, but WT plants accumulated more Hg in leaves and had a higher stomatal conductance, and root and shoot biomass compared with SGECd(t). Shoot excision resulted in greater root-pressure induced xylem exudation of SGECd(t) in the absence of Cd or Hg and following Cd exposure, whereas the opposite response or no genotypic differences occurred following Hg exposure. Exposing plants that had not been treated with metal to 50 mu M CdCl2 for 1 h increased root xylem exudation of WT, whereas 50 mu M HgCl2 inhibited and eliminated genotypic differences in root xylem exudation, suggesting differences between WT and SGECd(t) plants in aquaporin function. Thus, root water transport might be involved in mechanisms of increased tolerance and accumulation of Cd in the SGECd(t) mutant. However, the lack of cross-tolerance to Cd and Hg stress in the mutant indicates metal-specific mechanisms related to plant adaptation.
KW - Aquaporin
KW - cadmium
KW - drought
KW - mercury
KW - pea
KW - root sap flow
KW - water deficit
KW - ROOT HYDRAULIC CONDUCTIVITY
KW - AQUAPORIN GENE-EXPRESSION
KW - ABSCISIC-ACID
KW - PLASMA-MEMBRANE
KW - DRYING SOIL
KW - ACCUMULATION
KW - STRESS
KW - GROWTH
KW - CHANNELS
KW - DROUGHT
U2 - 10.1093/jxb/eru536
DO - 10.1093/jxb/eru536
M3 - Journal article
VL - 66
SP - 2359
EP - 2369
JO - Journal of Experimental Botany
JF - Journal of Experimental Botany
SN - 0022-0957
IS - 8
ER -