Raffinose accumulation related to desiccation tolerance during maize (Zea mays L) seed development and maturation

A comprehensive analysis of soluble carbohydrates in developing embryos of field-grown maize seed was used to establish the relationship of sucrose and raffinose levels and their mass ratio to the occurrence of desiccation tolerance in immature whole kernels and in isolated embryos. Kernel, endosperm, and embryo dry mass were maximum at 56 d after pollination (DAP). Freshly harvested seeds germinated between 64 and 86 DAP, but after fast drying at 12 % relative humidity, seeds germinated between 30 and 36 DAP and between 14 and 22 DAP after slow drying on the ear. Freshly harvested isolated embryos germinated between 14 and 16 DAP, between 26 and 45 DAP after fast drying, and between 18 and 22 DAP after slow drying. Sucrose accumulated independently of desiccation tolerance. Raffinose accumulation was not required for germination but was associated with survival after drying. Desiccation tolerance was not observed in the absence of raffinose accumulation, but the presence of small quantities of raffinose was not always associated with the onset of desiccation tolerance during early embryo development. Desiccation tolerance in maize embryos was associated with sucrose-to-raffinose mass ratios less than 20:1 and stage 2-3 in embryo development.