After this last stage, the size of the embryo increases and deposition of storage macromolecules begins.
After approximately 28 d, that deposition of storage reserves decreases and the grains begin to desiccate.
During seed development, deposition of storage reserves (proteins, lipids and carbohydrates) begins at the late immature stage and increases until the late maturation stage.
However, for many crops, the pathways followed by photoassimilates from their sites of synthesis to their deposition in storage tissues are not well defined.
Previous studies had reported that over-expression of BiP had inhibitory effect on protein translation, folding and deposition of storage proteins into rice endosperm [ 23, 24].
The third major transition starts at 28 DAA where deposition of storage reserve decreases [ 6] followed by physiological maturity to turn caryopsis brown.
Thus, both techniques, OCT and EM reveal a spatially corresponding deposition of storage material, confirming the reliability of the non-invasive autofluorescence imaging approach.
Growth is characterized by a period of active precursor biosynthesis, DNA synthesis and cell division [ 19, 20], and reserve accumulation is characterized by the biosynthesis and deposition of storage proteins, fatty acids and starch [ 21- 23].
More than 10% of the genes were found to be significantly differentially expressed (p < 0.01) in at least one stage studied, with the highest number of differentially expressed genes occurring during the phase of beginning deposition of storage materials.
In order to exploit all of these possibilities, it is necessary to understand the pathways and mechanisms which determine the synthesis, processing, trafficking and deposition of storage components in the developing grain.
