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  • Author or Editor: R. F. Carlson x
  • Journal of the American Society for Horticultural Science x
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Abstract

Methanol extracts of fresh tissues of ‘Mazzard’ (Prunus avium L.) and ‘Mahaleb’ (P. mahaleb L.) were examined for phenolic composition. The 2 sweet cherry rootstocks differed in 3 phenolic groups; phenolic acids, coumarins, and flavonoids. ‘Mazzard’ contained 5 acids; p-coumaric, o-coumaric, caffeic, p-coumarylquinic and chlorogenic, whereas ‘Mahaleb’ contained mostly o-coumaric acid. ‘Mahaleb’ tissues were rich in coumarin and herniarin, but these were absent in ‘Mazzard’. Three flavonoids; dihydrowogonin, kaempferol and quercetin, were found in ‘Mazzard’. ‘Mahaleb’ contained only kaempferol. These differences in phenolic composition between the 2 rootstocks seemed related to graft-incompatibility.

Open Access

Abstract

Five apple species were grafted onto East Mailing VII, IX and 26 and Mailing Merton 104, 106 and 111 and 3 cherry species were grafted onto Mazzard F12/1 rootstock (a virus indexed clone) and grown in the field for one season. Determinations were made on graft success and plant response in the field. In October, representative graft unions of the 33 combinations were prepared, sectioned, and examined microscopically in an effort to find a rapid test for compatibility. The results of these microscopic examinations were correlated with the field results to see if one or more abnormalities could be found consistently in a significant number of grafts. Only a few grafts showed incompatibility characteristics which could be correlated to the field tests thus eliminating a quick microscope test. Anatomical abnormalities appeared to be the result of secondary influences suggesting that the biochemical factors probably control the compatibility or incompatibility of graft unions.

Open Access

A study was undertaken to determine the seasonal dynamics of leaf and fruit K content and the influence of tree K status and fruit growth on leaf and fruit K accumulation rates in French prune (Prunus domestics L. cv. d'Agen). Mature trees in a commercial orchard were treated with various rates of K2 SO4. (O to ≈20 kg/tree) in the fall. Fruit dry weight yield per tree at harvest and fruit K content were higher for high-K trees, but fruit percent K (by dry weight) was ≈1.0% for all trees. Leaf scorch and subsequent abscission severely reduced the canopy of K-deficient trees. Significant positive linear relationships between leaf and fruit K accumulation rates existed for the periods of 28 Apr.-28 May (May) and 28 May-7 July (June). A significant negative linear relationship existed between these two criteria from 7 July-3 Aug. (July). May (0.237 mg K per fruit-day) and July (0.267 mg K per fruit-day) mean fruit K accumulation rates were similar, but both were significantly higher (P = 0.001) than those for June (0.140 mg K per fruit-day). Mean leaf K accumulation rates for May (- 0.007 mg K per leaf-day) and July (-0.010 mg K per leaf-day) were similar, but both were significantly (P = 0.001) less than for June (0.005 mg K per leaf-day). Potassium per fruit accumulation was highest in trees with highest K status. Periods of net leaf K efflux and influx did not precisely correlate with fruit growth stages measured by fruit dry weight. The period of lowest fruit K accumulation (28 May-7 July) coincided with the period of maximum dry matter accumulation by the kernel. After 7 July, all increases in fruit dry weight and K content were due to mesocarp growth.

Free access

Four adjacent heavily cropping 12-year-old `Petite d'Agen' prune (Prunus domestica L.) trees were selected, and two of the trees were defruited in late spring (28 May) after the spring growth flush and full leaf expansion. Trees received K daily through the drip-irrigation system, and 15N-depleted (NH4)2SO4 was applied twice between the dates of defruiting and fruit maturation. Trees were excavated at the time of fruit maturity (28 July) and fractionated into their component parts. The following determinations were made after tree excavation and sample processing: tree dry weight, dry weight distribution among the various tree fractions (fruit, leaves, roots, trunk, and branches), tree nutrient contents, within-tree nutrient distribution, total nonstructural carbohydrates (TNCs), and recovery of labeled N. Trees only recovered ≈3% of the isotopically labeled fertilizer N over the 6-week experimental period. Heavily cropping trees absorbed ≈9 g more K per tree (17% of total tree K content) during the 2-month period of stage III fruit growth than defruited trees. The enhanced K uptake in heavily cropping trees was apparently conditioned by the large fruit K demand and occurred despite greatly reduced levels of starch and TNCs relative to defruited trees. Fruit K accumulation in heavily cropping trees was accompanied by K depletion from leaves and perennial tree parts. Except for K, fruited and defruited trees did not differ in nutrient content.

Free access