Huerta, Alfredo J. , Nwugo, Chika .
The chelator EGTA and silicon act synergistically in protecting rice seedlings (Oryza sativa L.), against cadmium toxicity.
RICE is a major silicon-accumulator and recent studies have shown that Si plays a chelator-like role in inducing Cd tolerance in rice plants. Studies have also shown Cd-induced tolerance in plants due to EDTA (a synthetic chelator) treatment. EDTA and EGTA are very similar compounds both in structure and function. Thus, hydroponic studies were conducted to investigate the effects of Si and EGTA on rice (Oryza sativa L.) seedlings grown under Cd stress. Treatments were 0 or 1μM Cd (as CdSO4), 0 or 0.6 mM Si (as NaSi3O7) and 0 or 50 μM EGTA, factorially arranged in a randomized complete block design. All treatments were initiated when seedlings were 6 d old. To investigate the effects of possible interactions between silicon and EGTA on cadmium toxicity, CO2 response (A/Ci) curves, stomatal conductance (gs), transpiration (E), chlorophyll fluorescence, plant growth, and leaf Cd content were measured on 40 d old seedlings. Our results showed that in the absence of EGTA, Si caused a 35% decrease in Cd accumulation in the leaves of Cd-treated plants, while in the presence of both EGTA and Si, there was a 99% decrease in the leaf-Cd content of Cd-treated rice plants. Consequently, there was a significant reduction in Cd-induced inhibition of photosynthesis and growth in the presence of both Si and EGTA compared to when only either Si or EGTA was present. These results show that Si together with EGTA induce a synergistic protection from cadmium-induced damage to photosynthesis and growth in rice.
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1 - Miami University, Department of Botany, Oxford, Ohio, 45056, USA
Presentation Type: Poster:Posters for Topics
Location: Auditorium/Bell Memorial Union
Date: Tuesday, August 1st, 2006
Time: 12:30 PM