Protein metabolism of seeds of pigeonpea (Cajanus cajan (L.) Millsp.) cultivars during accelerated ageing
1997
Kalpana, R. | Madhava Rao, K.V. (Andhra University, Andhra Pradesh (India). Department of Botany)
Seeds of three cultivars of pigeonpea (Cajanus cajan (L.) Millsp.) - ICPL87, T21, and PDM1 - were subjected to accelerated ageing at 40 deg C and 100 % RH for 0, 2, 4, 6, and 8 days. The ageing of seeds led to a decline in viability. Reduction in protein content was accompanied by a rise in the level of amino acids, indicating degradation of proteins during the process of seed ageing. During initial imbibition the incorporation of 14C-L-leucine was greater in the 2 d and 4 d accelerated aged seeds than in the respective controls, indicating the probable operation of repair mechanisms. However, after 24 h the high quality seeds surpassed the deteriorated seeds in the utilisation of the radioactive substrate. Even after eight days of accelerated ageing the seeds revealed considerable ability to synthesise protein though to a lesser extent than the other seed lots. Thus, there appeared to be no complete loss of protein synthesis capacity under accelerated ageing conditions. Alterations in normal protein biosynthesis might however lead to greater synthesis of hydrolytic enzymes and hence seed deterioration. The hydrolytic enzyme proteinase exhibited a steady increase in activity with accelerated ageing and hence may play a critical role in pigeonpea seed deterioration. Cultivars showed marked differences in their response to ageing treatment
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