Mineral analysis from corkspotted and normal 'Anjou' pear fruit.
Curtis, D.; Righetti, T. L.; Mielke, E.; Facteau, T.;
Journal of the American Society for Horticultural Science Year: 1990 Vol: 115 Issue: 6 Pages: 969-974 Ref: 23 ref.
1990
บทคัดย่อ
Samples of fruits [Beurre d'Anjou] collected 1 or 2 months or immediately before harvest from 20 commercial orchards near Hood River, Oregon, in 1985 and 1986 were subjected to full mineral analysis, and assessed for firmness, quality and the incidence of disorders, particularly cork spot, after storage for 3-4 or 6-7 months. Additionally, healthy fruits and those affected by cork spot obtained from a packing line handling fruits from 5 identified orchards on the same day were divided into 6 tissue type subsamples for full mineral analysis. There were no significant relationships between average preharvest fruit mineral contents and the incidence of cork spot but the postharvest mineral contents of affected and healthy fruits were markedly different. Affected fruits had lower Ca concentrations and higher N:Ca ratios than healthy fruits. All types of tissue samples (peels, opposing tangential slices with or without peel, cortical tissue plugs from near the core or immediately inside the peel or core tissue together with seeds) showed similar trends. Concentrations in peel tissues correlated well with those in other tissues and were the easiest subsample to process. In either year, cork spot was absent when the peel N:Ca ratio was <6.3. A computer model was used to estimate the percentage of pears in each orchard with Ca concentrations lower than a given threshold value. It was difficult to predict the actual number of pears with low Ca concentrations from mean Ca concentrations when the overall average percentage of pears defined arbitrarily as low in Ca was small (<10%). It is concluded that strong correlations between mean Ca concentrations and the incidence of disorders commonly encountered in this area of Oregon should not be expected.