Tuber slices of newly introduced potato cultivars （cvs） in Libya, namely Spunta, Pamela, Daisy, Daifla, Atlas and Apollina were tested for their susceptibility to soft rot bacterium （Erwinia carotovora subsp, carot...Tuber slices of newly introduced potato cultivars （cvs） in Libya, namely Spunta, Pamela, Daisy, Daifla, Atlas and Apollina were tested for their susceptibility to soft rot bacterium （Erwinia carotovora subsp, carotovora）. Atlas cv was proved to be the most susceptible cv, meanwhile, Daisy cv was the most resistant one. The activities of pectolytic and oxidative enzymes in diseased tubers were profoundly higher than these in healthy ones. The highest enzymatic activities of pectin methyl esterase （PME） and polygalacturonase （PG） were observed in diseased tubers of Daifla cv. However, diseased tubers of Spunta gave the highest activities of polymethyl galacturonase （PMG）. On the other hand, the highest significant activities of the enzyme PME in healthy tubers was detected in Pamela cv compared to other cvs. Moreover, there were insignificant differences in PG and PMG enzymes activities between healthy tubers of the different cvs. The cv Daisy gave the highest activity of the enzyme peroxidase （PO） in diseased tubers, whereas the highest activity of enzyme polyphenol oxidase （PPO） was detected in infected tubers of Atlas cv. Concerning healthy tubers, the highest activities of enzymes PO and PPO were noticed in Atlas and Pamella cvs respectively as compared to other cvs. Electrolyte leakage from plant cells was estimated by measuring electrical conductivity as indicator for permeability changes in potato tissues. Values of electrolyte leakage in infected tubers of all tested cvs showed significant increase compared with those of healthy ones, especially, with the most susceptible one.展开更多
文摘Tuber slices of newly introduced potato cultivars （cvs） in Libya, namely Spunta, Pamela, Daisy, Daifla, Atlas and Apollina were tested for their susceptibility to soft rot bacterium （Erwinia carotovora subsp, carotovora）. Atlas cv was proved to be the most susceptible cv, meanwhile, Daisy cv was the most resistant one. The activities of pectolytic and oxidative enzymes in diseased tubers were profoundly higher than these in healthy ones. The highest enzymatic activities of pectin methyl esterase （PME） and polygalacturonase （PG） were observed in diseased tubers of Daifla cv. However, diseased tubers of Spunta gave the highest activities of polymethyl galacturonase （PMG）. On the other hand, the highest significant activities of the enzyme PME in healthy tubers was detected in Pamela cv compared to other cvs. Moreover, there were insignificant differences in PG and PMG enzymes activities between healthy tubers of the different cvs. The cv Daisy gave the highest activity of the enzyme peroxidase （PO） in diseased tubers, whereas the highest activity of enzyme polyphenol oxidase （PPO） was detected in infected tubers of Atlas cv. Concerning healthy tubers, the highest activities of enzymes PO and PPO were noticed in Atlas and Pamella cvs respectively as compared to other cvs. Electrolyte leakage from plant cells was estimated by measuring electrical conductivity as indicator for permeability changes in potato tissues. Values of electrolyte leakage in infected tubers of all tested cvs showed significant increase compared with those of healthy ones, especially, with the most susceptible one.
