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Development Home Germination Early growth and tillering Stem elongation Wheat apex development Flowering and fertilisation Pollen release Grain growth 1 to 4 days Grain growth 4 to 10 days Cell layers inside a grain Grain filling 11 to 16 days Grain filling 17 to 21 days Grain filling 21 to 30 days Development of the embryo A globular shape 0-7 days Differentiation 11-16 days Embryo growth completed
Dry down 30 to 40 days How we grew the plants Photography and microscopy
DAYS = days after flowering
Development Home Germination Early growth and tillering Stem elongation Wheat apex development Flowering and fertilisation Pollen release Grain growth 1 to 4 days Grain growth 4 to 10 days Cell layers inside a grain Grain filling 11 to 16 days Grain filling 17 to 21 days Grain filling 21 to 30 days Development of the embryo A globular shape 0-7 days Differentiation 11-16 days Embryo growth completed
Dry down 30 to 40 days How we grew the plants Photography and microscopy
DAYS = days after flowering
Development of the embryo
Differentiation 11-16 days
 | The embryo is developing rapidly and at 11 days after flowering has elongated. Its position on the dorsal side of the grain is established early on. Compare its size here with the embryo at 15 days after flowering. Densely cytoplasmic cellular endosperm is still present at 11 days after flowering. The embryo has been supported by these reserves up to now, but this will change in the next few days. |
 | The above section in Darkfield shows starch grains starting to form in the endosperm close to the embryo. This will be the developing embryo's new source of nutrients. Starch is still abundant in the maternal pericarp. |
 | In Darkfield we see the rapid accumulation of starch in the endosperm. However, the area close to the scutellum develops differently as its starch reserves are used for the growth of the embryo. |
 | 15 days after flowering. Within the past four days the scutellum has differentiated and the two embryonic poles are now recognizable as shoot and root. The scutellum is the organ that will transfer nutrients from the endosperm to the embryo both now, during grain filling, and later when the seed germinates and the growth cycle starts again. It is the large shield-like structure attached to the embryo but here in longitudinal section we see only a thin slice. Go to the whole grain photographs and the micrographs in Grain Filling 2 and 3 to see where it lies between the embryo and the endosperm. The densely cytoplasmic cellular endosperm has been completely used by 15 days after flowering. |
 | This highly magnified section, at 11days after flowering, shows more detail of the embryo. Cellular patterning is seen in the root pole. The cleft on the dorsal side (arrowed) defines the point of separation of the epicotyl, the primordial shoot, from the scutellum. A group of cells on the dorsal side are highly meristematic and will soon differentiate into the shoot apex. The cellular endosperm declines and, as the scutellum develops, the embryo will be supported from the starch reserves in the main body of the endosperm. |
 | Each day brings further development of the scutellum and differentiation of the three elements of the embryonic axis; shoot, root and mesocotyl. In this section the primordial shoot apex can be seen inside the coleoptile. 16 days after flowering. |