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The contents and the compositions of total free amino acids were investigated in the rice(Oryza sativa L. cv. Chucheong) seedlings under low temperatures. Activitiess of some enzymes associated with the markedly changed amino acid content were also investigated. Under low temperature, the contents of soluble protein and the total free amino acids increased, while the content of total nitrogen decreased. Althoughh asparagine+glycine were the most abundant amino acid species in the rice seedlings at the control temperature, low temperature treatment for 3days brought about the decrease in their amount to about 60% level of the control plants. On the other hand, alanine showed the highest increase in the content among all the free amino acids, though glutamine, proline, aspartic acid, valine and tyrosine also incresased after low temperature treatment. To elucidate the decrease of asparagine_glycine level under low temperature, the activities of asparagine aminotransferase and asparaginase which metabolize asparagine were investigated in the rice seedlings under low temperature. The activity of asparaginase increased markedly, while that of asparagine aminotransferase decreased under low temperatures. Therefore, it was suggested that asparaginase metabolizes asparagine predominatly in the rice seedlings under low temperatures.
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