Effects of Nuclear Genomes on Anther Development in Cytoplasmic Male Sterile Chicories (Cichorium intybus L.): Morphological Analysis

Figure 5

Anther and pollen development in fertile CC line and in 524CC male sterile anther. (a) At anthesis, the fertile anther is blue colored and the sterile is brown and shriveled; the stylar branches (st) arising on the top of the anther column (ac) are normal and blue colored in both cases. ((b), (d), (f), and (h): fertile anthers; (c), (e), (g), and (i): sterile anthers). (b)-(c) Free microspore stage (stage 10). In fertile flower (b) the tapetum has larger vacuoles (arrow heads) and in male sterile flower (c) the vacuoles are numerous but smaller and less significant intrusion of tapetal cells is observed at this stage (). (d)-(e) Vacuolated uninucleate pollen grain stage (stage 11). The endothecium (en) expansion is noticeable in (d) not in (e) where the pollen cytoplasm is diffuse (arrow head). (f)-(g) Two-celled pollen grain (stage 13), (f) connectivum and endothecium cell undergo wall lignification (arrow heads), (g) absence of cell wall lignification in the connectivum and endothecium, pollen abortion (), shrinkage of endothecium (arrow head) and septum (se) not opened (arrow). (h) The connectivum (co) and endothecium are lignified and the anther is dehiscent. (i) The septum and stomium (st) are unopened (arrow head). The pollen grain is degenerated (arrows), the connectivum is not lignified, and the anther is indehiscent. Bars 2 mm in (a), 20 μm in (b)–(i).

(a)

(b)

(c)

(d)

(e)

(f)

(g)

(h)

(i)