Journal of Experimental Botany, Vol. 53, No. 371, pp. 1177-1185,
May 2002
© 2002 Oxford University Press
Original Papers |
Cadmium accumulation and buffering of cadmium-induced stress by arbuscular mycorrhiza in three Pisum sativum L. genotypes
1UMR 1088 INRA/Université de Bourgogne, BBCE-IPM, INRA-CMSE, BP 86510 21065 Dijon Cédex, France
2Laboratoire de Bioénergétique, Université de Genève, 1254 Jussy-Lullier, Genève, Switzerland
3Institute of Botany, Jagiellonian University, ul. Lubicz 46, 31512 Kraków, Poland
4All Russia Research Institute for Agricultural Microbiology, Podbelsky Shossee 3, St.-Petersburg-Pushkin 8, 189620 Russia
5Departamento El Hombre y su Ambiente, CBS, Universidad Autónoma Metropolitana-Xochimilco, Calz. del Hueso 1100, Col. Villa Quietud, 04960 México DF, México
The role of arbuscular mycorrhiza in reducing Cd stress was investigated in three genotypes of Pisum sativum L. (cv. Frisson, VIR4788, VIR7128), grown in soil/sand pot cultures in the presence and absence of 23 mg kg-1 bioavailable Cd, and inoculated or not with the arbuscular mycorrhizal fungus Glomus intraradices. Shoot, root and pod biomass were decreased by Cd in non-mycorrhizal plants. The presence of mycorrhiza attenuated the negative effect of Cd so that shoot biomass and activity of photosystem II, based on chlorophyll a fluorescence, were not significantly different between mycorrhizal plants growing in the presence or absence of the heavy metal (HM). Total P concentrations were not significantly different between mycorrhizal and non-mycorrhizal plants treated with Cd. From 2050-fold more Cd accumulated in roots than in shoots of Cd-treated plants, and overall levels were comparable to other metal-accumulating plants. Genetic variability in Cd accumulation existed between the pea genotypes. Concentration of the HM was lowest in roots of VIR4788 and in pods of VIR4788 and VIR7128. G. intraradices inoculation decreased Cd accumulation in roots and pods of cv. Frisson, whilst high concentrations were maintained in roots and pods of mycorrhizal VIR7128. Shoot concentrations of Cd increased in mycorrhizal cv. Frisson and VIR4788. Sequestration of Cd in root cell walls and/or cytoplasm, measured by EDS/SEM, was comparable between non-mycorrhizal pea genotypes but considerably decreased in mycorrhizal cv. Frisson and VIR7128. Possible mechanisms for mycorrhiza buffering of Cd-induced stress in the pea genotypes are discussed.
Key words: Cadmium, Glomus intraradices, pea genotypes, phytoremediation.