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Title: Arsenic uptake, metabolism and toxicity in paddy rice (Oryza sativa L.)
Author: Abedin, Md. Joinal
ISNI:       0000 0001 3390 8080
Awarding Body: University of Aberdeen
Current Institution: University of Aberdeen
Date of Award: 2002
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The use of arsenic contaminated groundwater for crop irrigation has resulted in elevated arsenic concentrations in the agricultural soils of Bangladesh. Rice is the main crop and a vast quantity of ground water is needed for its cultivation, especially in the dry season. The presence of high concentrations of arsenic in the soil and continuing use of arsenic contaminated irrigation water may affect the rice germination, early seedling growth, uptake and accumulation of arsenic in rice plant parts. A germination study with eight Bangladeshi rice varieties showed that Purbachi was the only variety which showed tolerance up to 4 mg As L-1 for arsenite and up to 8 mg As L-1 arsenate. In a seedling toxicity experiment, no varietal resistance was observed for either arsenite or arsenate. Arsenic toxicity to rice seedling resulted in inhibition of root growth and reduced shoot height. High affinity uptake (0 to 0.0532 mM) kinetics for arsenite and arsenate with 8 rice varieties, covering two growing seasons, Boro (dry season) and Aman (wet season), showed that uptake of both arsenite and arsenate by Boro varieties was less than that of Aman varieties. Arsenite uptake was carrier-mediated, and was taken up at approximately the same rate as arsenate at lower substrate concentrations (high affinity range), while at higher substrate concentrations (low affinity uptake range) uptake of arsenite was much higher than arsenate. Suppression of arsenate uptake was observed with increasing phosphate concentration, while the uptake of arsenite was independent of phosphate concentration indicating that arsenite was not taken up into root by phosphate transporter. Uptake of organic arsenic species was much lower than that of organic species. In long-term growth experiments, rice growth and yield were affected significantly by arsenate containing irrigation water. Arsenic concentrations in rice root, straw, husk and grain increased significantly with increasing arsenate concentration in irrigation water.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available