摘要：Rice (Oryza sativa) is an important food crop in India as well as in other Asian countries. It is well known thatcompounds of heavy metals are known to harm land plants, and plant parts and aluminium is one such anelement causing toxic effects in plants particularly in plant growing in marshy and acidic soils. Senescenceis characterized by the results of many sequential molecular events and these are influenced by biotic andabiotic factors. The present study was carried out systematically on the toxic effects of aluminium in thedetached rice leaves during leaf senescence with reference to starch metabolism and its associated enzymes.In our study reducing and non-reducing sugars were increased and starch content decreased. Significantincreases were observed in reducing and non-reducing sugars and their associated enzymes such asstarch phosphorylase and sucrose synthase in both Aduthurai 43 (ADT-43) and Pro Agro 6129 (PA 6129)varieties and decreased activity of α-amylase was observed with the increasing periods of exposure andincreasing concentration of aluminium in leaves of rice varieties in detached leaves during leaf senescence.However, the shifts in the non-reducing sugars were greater in ADT 43, when compared to PA 6129. Theshifted carbon partitioning from non-soluble carbohydrate to soluble carbohydrates significantly contributedto osmotic adjustment in ADT 43 and it indicates that it is tolerant to aluminium toxicity.
