Microscopic Analyses of Fruit Cell Plastid Development in Loquat (<i>Eriobotrya japonica</i>) during Fruit Ripening
Pengjun Lu,
Ruqian Wang,
Changqing Zhu,
Xiumin Fu,
Shasha Wang,
Don Grierson,
Changjie Xu
Affiliations
Pengjun Lu
Zhejiang Provincial Key Laboratory of Horticultural Plant Integrative Biology, College of Agriculture and Biotechnology, Zhejiang University, Zijingang Campus, Hangzhou 310058, China
Ruqian Wang
Zhejiang Provincial Key Laboratory of Horticultural Plant Integrative Biology, College of Agriculture and Biotechnology, Zhejiang University, Zijingang Campus, Hangzhou 310058, China
Changqing Zhu
Zhejiang Provincial Key Laboratory of Horticultural Plant Integrative Biology, College of Agriculture and Biotechnology, Zhejiang University, Zijingang Campus, Hangzhou 310058, China
Xiumin Fu
South China Botanical Garden, Chinese Academy of Sciences, Xingke Road 723, Tianhe District, Guangzhou 510650, China
Shasha Wang
Zhejiang Provincial Key Laboratory of Horticultural Plant Integrative Biology, College of Agriculture and Biotechnology, Zhejiang University, Zijingang Campus, Hangzhou 310058, China
Don Grierson
Zhejiang Provincial Key Laboratory of Horticultural Plant Integrative Biology, College of Agriculture and Biotechnology, Zhejiang University, Zijingang Campus, Hangzhou 310058, China
Changjie Xu
Zhejiang Provincial Key Laboratory of Horticultural Plant Integrative Biology, College of Agriculture and Biotechnology, Zhejiang University, Zijingang Campus, Hangzhou 310058, China
Plastids are sites for carotenoid biosynthesis and accumulation, but detailed information on fruit plastid development and its relation to carotenoid accumulation remains largely unclear. Here, using Baisha (BS; white-fleshed) and Luoyangqing (LYQ; red-fleshed) loquat (Eriobotrya japonica), a detailed microscopic analysis of plastid development during fruit ripening was carried out. In peel cells, chloroplasts turned into smaller chromoplasts in both cultivars, and the quantity of plastids in LYQ increased by one-half during fruit ripening. The average number of chromoplasts per peel cell in fully ripe fruit was similar between the two cultivars, but LYQ peel cell plastids were 20% larger and had a higher colour density, associated with the presence of larger plastoglobules. In flesh cells, chromoplasts could be observed only in LYQ during the middle and late stages of ripening, and the quantity on a per-cell basis was higher than that in peel cells, but the size of chromoplasts was smaller. It was concluded that chromoplasts are derived from the direct conversion of chloroplasts to chromoplasts in the peel, and from de novo differentiation of proplastids into chromoplasts in flesh. The relationship between plastid development and carotenoid accumulation is discussed.
