Foliar- and Fruit-applied Strontium as a Tracer for Calcium Transport in Apple Trees

摘要: Application of calcium (Ca) sprays is a recommended practice to reduce the inci- dence Ca-related disorders such as bitter pit in apple (Malus ×domestica), but effectiveness increase Ca concentrations fruit not always consistent. Strontium (Sr) has been used analog evaluate transport processes and distribution plants. A fi eld study was conducted using foliar- fruit-applied Sr tracer for 20-year-old 'Honeycrisp' trees on Malling.26 (M.26) rootstock. The objectives this were 1) measure amount translocation from leaves fruit, 2) deter- mine eight applied over growing season vs. four late-season increasing 3) effect an experimental adjuvant consisting alkyl-polysaccharides monosaccharides spray effi cacy. Seven treatments tested, which included control six ap- plied various combinations with or without adjuvant. Trees sprayed times during season, either directly only (fruit covered application). Spray did signifi cantly affect total fresh dry weight. Although some discrimination between detected, similar tissue suggested that suitable Ca. Based uncovered treatments, about 11% 17% came leaves. Eight applications more than doubled both concentration content compared late sprays. tested absorption by Assuming Sr, adjusting atomic weight relative maximum at harvest foliar (eight fruit) would have follows: core = 78 mg·kg -1 ; fl esh 35 peel 195 entire 67 . In addition being underused tool studying patterns, results also suggest use may be novel technique testing cacy adjuvants enhance uptake fruit. Quality storability are often strongly associated levels