Abstract

                                Studies on the pathophysiology of the CSMV-infected cassava loaves with parti cular reference to nitrogen metabolism was taken up. The results showed a reduction in the total nitrogen content in the mosaic infected leaves at all sampling periods when compared to healthy and diseased leaves. Maximum total nitrogen was noted in samples collected in the early morning than in the samples taken subsequently. These observed diurnal fluctuations on the synthesis of various nitrogen fractions and the pattern of vari ous nitrogen fraction contents were found to be more or less same in both healthy and diseased leaves, but the disease exaggerated the conditions either by increasing or decreasing the content. The CN ratio also varied according to the time of sampling and most of the times the ratio was less in diseased samples than the healthy ones. Diseased leaves contained higher quantity of bound amino acids and the maximum level reached 15 days aftor grafting. Asparagine was found to accumulate more in the diseased leaves when compared to the healthy leaves,

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