Difference Of Epidermal Structure Of Red Fuji Apple Under Different Site Conditions And Its Relationship With Cracking

Red Fuji apples were used to study the difference of pericarp anatomical structures inapples from different site conditions by observing pericarp anatomical structures. Andmorphological courses of cracking were illustrated by observing the cracking position inapple fruit from one site condition. The main results were as follows:1. From48days after full bloom (DAFB) to186DAFB, thickness of cuticle layer incheeks was thicker than that in stem cavity and calyx-end, and showed significantdifference; epidermal cell size in cheeks was bigger than that in stem cavity and calyx-end.2. Loosened epidermal cells appeared earlier in bagged fruits than in nobagged fruits.Gaps existed between epidermal cells and were filled with cutin. And there were fewergaps in bagged fruits than in nobagged fruits.3. Thickness of cuticle layer in nobagged fruits was thicker than that in bagged fruits,and epidermal cell size and pericarp thickness were both smaller than those in baggedfruits.4. Cracking occurred at121DAFB and138DAFB in bagged and nobagged fruitsseparately. Cracking percentage was higher in bagged fruits than that in nobagged fruits.From121DAFB to138DAFB, cracking percentage in stem cavity, cheeks, calyx-end inbagged fruits was higher than that in nobagged fruits at the same period, and crackingpercentage in stem cavity and cheeks was higher than that in calyx-end.5. Thickness of cuticle layer was thicker and epidermal cell size was bigger in fruitsfrom orchards with higher air relative humidity, higher mean daily temperature and moredays above35degrees than in other orchards.6. Thickness of cuticle layer was thicker and epidermal cell size was smaller in applefruits in orchards with lower relative humidity and higher mean daily temperature.7. The forming process of fruit cracking in Red Fuji apple was gradual but not suddenand the cracking was originated from cuticle.