Physiological Studies on Postharvest Deterioration of Cassava Roots

JARQ : Japan Agricultural Research Quarterly
ISSN 00213551
書誌レコードID(総合目録DB) AA0068709X

 A series of experiments were carried out to know the details of root deterioration process, and to examine changes in respiration and ethylene production in cassava roots and tissue blocks in relation to physiological deterioration. The following results were obtained:
(1) Two distinct types of deterioration were observed, one was a ring of brownish or blue-brownish coloration in the intervening part between the outermost part and the innermost part of parenchymatous tissue, and the other was the softened and discolored tissues infected by many kinds of fungus. The 2 types of deterioration are distinguished as physiological (PD) and microbial deterioration (MD), respectively, as described by Lozano et al..
(2) Twelve cultivars, 15 months of age, were tested for susceptibility or resistance to PD. It was proved that varietal difference in PD was seen more clearly and earlier in tissue blocks than intact roots. The degree of PD was negatively correlated with moisture content of roots at harvest, and positively correlated with root starch content.
(3) Pruning treatment, leaving only 30 cm of the stem, practiced 2 to 3 weeks before harvest or burying roots underground for 3 weeks was effective in delaying the occurrence of PD.
(4) Respiratory rates of root pieces taken from artificially injured roots increased rapidly reaching a peak one day after harvest and another maximum peak 4 or 5 days later. The first peak was regarded wound respiration and the second one is caused by biochemical changes related to development of PD.
(5) Varietal difference in respiratory rate was observed.
(6) Ethylene was produced in root slices in detectable concentration 15 to 16 hr after incubation, reaching maximum value after one day of incubation. Varietal difference in the amount of ethylene production was observed.
(7) The amount of ethylene produced in root tissue blocks taken from pruned plants was slightly different from that taken from unpruned plants. Ethrel applied to root tissue blocks showed no or little effect on respiratory rate of the tissue blocks. Only a slight progress of PD was observed in ethrel-treated root tissue blocks. It appears that this tendency was similar to both root tissue blocks taken from pruned and unpruned plants.
(8) Thus, it was difficult to make clear the effect of pruning treatment on ethylene production and respiratory rate of roots, probably due to the use of root tissue blocks as experimental material.

国立情報学研究所メタデータ主題語彙集(資源タイプ) Journal Article
開始ページ 241
終了ページ 252
言語 eng