Kernel Structure and Embryo Oil Accumulation in Maize Fruits Differing in Oil Concentration at Maturity by Pollen Source

TANAKA, W; MANTESE, A. AND MADDONNI, G. A.

ANNALS OF BOTANY

Oxford Univesrsity press

Lugar: Oxford; Año: 2009 vol. 104 p. 325 - 334

0305-7364

• Background and Aims. Previous studies have reported pollen source effect on oil concentration of maize (Zea mays, L.) kernels through modifications of both embryo-kernel ratio and embryo oil concentration. In this work we have broaden previous analysis by addressing pollen source effect on kernel structures (i.e. pericarp, endosperm and embryo) growth, embryo chemical constituents (i.e. oil, protein, starch and soluble sugars) allocation, and the anatomy and histology of the embryos. • Methods. Maize kernels with different oil concentration were obtained from pollinations with two parental lines of contrasting oil concentration. The dynamics of kernel structures growth and embryo chemical constituent’s allocation were analyzed during the grain filling period. Mature kernels, were dissected to study the anatomy (embryonic axis and scutellum) and the histology (cell number and cell size of the scutellums, presence of sub-cellular structures in the scutellum tissue: starch granules, oil and protein bodies) of the embryos. • Key Results. Pollen source determined a non documented trade off between embryo and endosperm growth rates (r2 = 0.54, P< 0.12) which impacted on the embryo-kernel ratio of mature kernels. Modifications of embryo size were mediated by pollen source effect on embryo cell number (P < 0.10). Pollen source also affected (P < 0.01) embryo chemical compounds allocation. Negative relationships (r2 = 0.91-0.98, P< 0.01) among final embryo oil concentration and those of the other compounds were found. Embryos with a low oil concentration had an increased (P < 0.05-0.10) scutellum cell area occupied by starch granules and a decreased oil body’s presence. • Conclusions. Our studies highlighted pollen source effect on embryo/endosperm ratio and embryo chemical compounds for kernel oil production. These pollen effects could also determine kernel performance for several industrial processes (wet and dry milling) based on kernel characteristics, such as endosperm/kernel ratio and endosperm vitreousness.