The effect of IAA on apical dominance in apple buds was examined in relation to changes in proton density (free water) and membrane lipid composition in lateral buds. Decapitation induced budbreak and enhanced lateral bud growth. IAA replaced apical control of lateral buds and maintained paradormancy. Maximal inhibition was obtained when IAA was applied immediately after the apical bud was removed; delaying application reduced the effect of IAA. An increase in proton density in lateral buds was observed 2 days after decapitation, whereas the change in membrane lipid composition occurred 4 days later. Removing the terminal bud increased membrane galacto- and phospholipids and the ratio of unsaturated to corresponding saturated fatty acids. Decapitation also decreased the ratio of free sterols to phospholipids in lateral buds. Applying thidiazuron to lateral buds of decapitated shoots enhanced these effects, whereas applying IAA to the terminal end of decapitated shoots inhibited the increase of proton density and prevented changes in membrane lipid composition in lateral buds. These results suggest that change in water movement alters membrane lipid composition and then induces lateral bud growth. IAA, presumably produced by the terminal bud, restricts the movement of water to lateral buds and inhibits their growth in apple.
Shiow Y. Wang, Miklos Faust, and Michael J. Line
Gerson R. de L. Fortes and Silvio L. Teixeira
The aim of this work was to study different apple of somatic material as callus and adventitious shoots are concerned, for further utilization in the research of somaclonal variation. The somatic materials were: leaf discs, cotyledons and hypocotyls of Gala apple seedlings, cultivated in a MS medium added by B5 vitamins in addition to (in mg/l): BAP (1,0), NAA (0,5) mio-inositol (100,0) sucrose (30,0 g/l) and solidified in agar (6,0 g/l). The several times of explant exposition to the dark affected the final callus weight. Callus weight derived from leaf discs were higher than those for cotyledons and hypocotyls. Explants exposed directly under light or up to two weeks in the dark showed less percentage of regenerative callus as compared to those of three weeks in the dark. The leaf explants presented the highest percentage of regenerative callus. The least response was obtained for those derived from hypocotyls. The highest number of adventitious shoots was obtained keeping the explants three weeks in the dark as compared to directed light exposition.
Raquel Gomez and Lee Kalcsits
‘Honeycrisp’ is among the most widely grown apple cultivars in the United States and ‘WA 38’ is a new apple cultivar released in Washington State. ‘Honeycrisp’ is highly susceptible to bitter pit and other physiological disorders; however, ‘WA 38’ is not susceptible to bitter pit but little is known about its susceptibility to other disorders. Bitter pit is a calcium-related disorder that has been associated with localized calcium deficiencies in fruit in addition to the proportions of calcium relative to the presence of other nutrients like potassium and magnesium. The objective of this study was to compare physiological differences and fruit quality between ‘Honeycrisp’ and ‘WA 38’ to determine how these differences might correspond to differences in mineral nutrient composition and bitter pit susceptibility. Here, ‘Honeycrisp’ and ‘WA 38’ elemental composition in leaves, fruit, and xylem sap was measured every 20 days starting 30 days after full bloom and compared with leaf gas exchange and stem water potential. ‘Honeycrisp’ had greater foliar transpiration rates that corresponded with greater calcium in the leaves and lower leaf K+Mg/Ca ratio, when compared with ‘WA 38’. In contrast, fruit calcium concentrations were higher for ‘WA 38’ with lower K+Mg/Ca ratios. Xylem conductance was higher during late summer in ‘WA 38’ compared with ‘Honeycrisp’. ‘WA 38’ fruit was denser than ‘Honeycrisp’ and more research is needed to determine whether differences in fruit structure may affect susceptibility to bitter pit in apple.
Jinxin Wang, Tao Luo, He Zhang, Jianzhu Shao, Jianying Peng, and Jianshe Sun
Apple ( Malus domestica Borkh.) is one of the most important fruit trees in the world. However, due to the infrequent formation of flower buds during its growth, apple fruit production is significantly affected; therefore, the mechanism of apple
Rui Sun, Hui Li, Qiong Zhang, Dongmei Chen, Fengqiu Yang, Yongbo Zhao, Yi Wang, Yuepeng Han, Xinzhong Zhang, and Zhenhai Han
Postharvest Biol. Technol. 22 197 204 Hokanson, S.C. Szewc-McFadden, A.K. Lamboy, W.F. McFerson, J.R. 1998 Microsatellite (SSR) markers reveal genetic identities, genetic diversity and relationships in a Malus domestica Borkh. core subset collection Theor
Jinwook Lee, In-Kyu Kang, Jacqueline F. Nock, and Christopher B. Watkins
, F. Biasioli, F. 2012 Texture dynamics during postharvest cold storage ripening in apple ( Malus × domestica Borkh.) Postharvest Biol. Technol. 69 54 63 Curry, E. 2008 Effects of 1-MCP applied postharvest on epicuticular wax of apples ( Malus
Soon-Il Kwon, Jeong-Hee Kim, Sun-Ae Kim, Young-Soon Kwon, and Jinwook Lee
‘RubyS’ ( Malus domestica Borkh.) apple cultivar was developed from Korean Apple Breeding Program, at Apple Research Institute, National Institute of Horticultural & Herbal Science (NIHHS), Rural Development Administration (RDA), Republic of Korea
Anton J. Bongers, Lawrence A. Risse, and Vincent G. Bus
Comparisons were made of the major physical and chemical characteristics of seven cultivars of apples (Malus domestica Borkh.) produced and imported into Western Europe from 13 origins. During the 1990-91 marketing season, `Delicious', `Golden Delicious', `Granny Smith', `Elstar', `Jonagold', `Gala', and `Fuji' apples were included in the study. Physical characteristics evaluated were length-to-diameter ratio, shape, external defects, internal defects, water core, bruises, firmness, blush surface, and color. Chemical characteristics evaluated were starch, juice content, soluble solids, acids, and ascorbic acid. Significant differences in some of these quality characteristics were found between the different origins. Apples produced in the United States, particularly `Delicious', had some superior quality characteristics compared to fruit from other origins.
Young Soon Kwon, Soon-Il Kwon, Jeong-Hee Kim, Moo Yong Park, Jong Taek Park, and Jinwook Lee
‘Arisoo’ is a red apple ( Malus ×domestica Borkh.) that ripens in early September. It was selected from a hybrid population of a cross between ‘Yoko’ ( Cummins, 1991 ) and ‘Senshu’ ( Soejima et al., 1998 ) in 2010 at the Apple Research Institute
Jinwook Lee, James P. Mattheis, and David R. Rudell
incidence of physiological disorders, including shriveling, cracking, and flesh breakdown, in cold-stored ‘Royal Gala’ apples. Materials and Methods Plant material and fruit storage. ‘Royal Gala’ apples ( Malus × domestica Borkh.) harvested from mature