Nonstructural Carbohydrate Partitioning in Perennial Parts of Sweet Cherry

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.