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  • Author or Editor: John Keller x
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Abstract

Nonstructural carbohydrates of sweet cherry (Prunus avium L. ‘Bing’) changed dramatically both qualitatively and quantitatively during the year. In perennial tissues, total nonstructural carbohydrates (TNC) were highest at leaf abscission. TNC increased sharply in spurs at budbreak, but, in other perennial tissues, reserves decreased with or before budbreak. TNC in all but spurs were least, e.g., 2% to 4% of fall levels, shortly after full bloom, but then immediately began to increase. Accumulations slowed during the last 4 to 6 weeks of fruit growth and then increased after harvest. Prebloom decreases and postbloom increases occurred earlier in 1- and 2-year-old shoots when compared to trunk or root tissues. Starch was the most common storage material. During winter, interconversion of starch and soluble carbohydrates in wood of the trunk and 1- and 2-year-old shoots was apparent. Sucrose was the predominant soluble carbohydrate during dormancy, but sorbitol dominated during active growth. Raffinose was present only during dormancy, and inositol only when leaves were present. Because sweet cherry flowers and fruits early, carbohydrate reserves could critically affect productivity.

Open Access

Abstract

Source–sink relationships in sweet cherry were altered by girdling limbs both above and below fruiting spurs. Spurs isolated by girdling both above and below had lower total fruit weight per spur and lower weight per fruit then those above or below girdles. Fruit number per spur was not altered, but soluble solids and fruit color were lower in fruits from isolated spurs than fruit from spurs either above or below girdles. Fruit on spurs above girdles were generally highest in soluble solids and fruit color. These factors indicate fruit on isolated spurs also were delayed in maturity. Spurs below girdles were unaffected by girdling. Girdling had no effect on spur leaf net photosynthesis, stomatal conductance, or fruit water loss rate. The results indicate that spur leaves alone do not have the capacity to support fruit growth in sweet cherry and must, therefore, be supplemented by photosynthates from other sources.

Open Access