Fiber initials represent a minority of epidermal ovule cells and identification of epidermal cells that develop into fibers is difficult before 0 dpa.
Staining of cellular Ca+2 indicated that fiber initials had more Ca+2 than other ovule cells supporting a role for Ca+2 in fiber development.
A view of the cut section of a stained 3 dpa ovule illustrated the contrast between the small fibers and other ovule cells and that the increase in ER persisted in fibers to at least 3 dpa (Fig. 3A).
Digitalization of the DiOC stained image and counting DiOC stained ovule cells will allow us to develop protocols to identify cotton germplasms and mutations with increased density of fibers and follow the trait as it is crossed into elite germplasms.
The A. thaliana mutants, ino [ 9] and pop2 [ 10] point to a role for diploid ovule tissue in pollen tube guidance; these have aberrant interactions between pollen tubes and diploid ovule cells, yet their female gametophytes appear normal, and in the case of pop2, can be fertilized with wild-type pollen [ 11].
In addition, they reveal previously unreported functions of AN in several biological processes, such as ovule development, cell morphogenesis in floral meristems, and root hair patterning.
Some genes potentially involved in ovule and cell identity, like HpINO, did not reveal any differential expression between sexual and apomictic genotypes.
Approximately 25% of the ovule epidermal cells differentiate into fiber cells during the initiation stage of cotton fiber development and subsequently undergo a period of rapid elongation known as the elongation stage [ 2, 3].
Cotton seed fibers are initially ovule epidermal cells that terminally differentiate into fiber cells typically on the DOA.
In plants Dmc1 transcripts are found in PMCs and ovule meiotic cells [ 60] and sporadically in mitotic cells [ 61].
Cotton seed fibers are single-celled trichomes that initiate from the ovule epidermal cells on or about the day of anthesis (DOA) [ 1].
