3.1 Establishment of anther length with timeline and cell type
specification in the anther
Anther development from primordium within developing spikelets on a
spike to a pollen shed, corresponding to anther lengths of 100 to 2300
µm (or more depending on the cultivar), respectively. Subsequently,
anther length is gradual and goes to stabilization. To correlate length
and time, anthers were dissected from spikelets of spike and the
neighboring spikelets were dissected minimum 24 h later from the same
position. In Figure 1 , results showed that anthers got double
in length from 100 to 200 µm in 2.5 days in the passage from day 1 to
3.5, and double again to 400 by day 7, and then the elongation in length
decrease gradually over the 32 days to achieve 2300 µm. The floral
meristem consists of three germ layers: namely L1, L2, and L3, which are
involved to make pollen grains finally in the last stage. Except the
EPI, vascular system (VS) and connective tissue (CT), which are the
result of division of L1 and L3 cells, respectively, while L2 form AR
cells from the four corners of each anther primordium. The mitotic
division of the AR cells occur which produce EN, SPL and PMC cells. The
SPL then divide to form ML and TA cells. Subsequently, PMC undergoes
meiosis to form Tds, which differentiate into MP rapidly and MP
differentiate into PG after cell division. The AR cells appear in
< 150 µm anthers and then disappear at > 150 µm
after formation of EN, SPL and PMC cells. Subsequently, SPL cells
disappear almost at 400 µm after formation of ML and TA cells.
Similarly, PMC cells disappear near to 700 µm after the formation of
microspore (MP) which differentiate into pollen grain (PG) which
released in the environment by opening the epidermal cells from stomium
region.