Endosperm - Pollen Biology
The examination of live material of j. montana reveals that the division of the primary endosperm nucleus is transverse, followed by the laying down a wall. The chalazal chamber divides by a vertical wall. The elongated tubular zygote is 60-80 pm long, and the growth rate is 5-6 pm per hour. The mitotic cycle of the endosperm nuclei is short as compared to that in somatic cells. It is also possible to analyses the rhythm of development of endosperm and embryo during the initial few stages. The information would help in finding out ways to prevent embryo abortion in distant hybridization. Enzymological studies on endosperm during development point out variable activities of different enzymes. Free-nucleate endosperm cells of Lilium regale show high activity of 6-PGDH and G6PDH until cellularization process begins.
The most active period of nitrogen accumulation in maize coincides with a rapid increase in glutamate synthase. Even differences between the normal and opaque-2 maize endosperm can be marked by analyzing isoenzyme profiles. At day 15, the normal endosperm shows proteases I and II, whereas, opaque-2 exhibits only I at both the ages. The localisation of three isoenzymes of G6PDH in the plastids and one in cytosol of developing castor endosperm reflects that young castor endosperm is the seat of both, glycolytic and pentose phosphate pathways. The embryo-endosperm relationship and the role of endosperm during seed development is an important aspect needing further attention.