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

Figure 6

Morphology of flowers and pollen viability in the parents and progenies of crosses with CC and Jupiter pollen donors. (a)–(c) Male fertile flowers: the anthers are blue and the stigma brushing hairs collect pollen grains at anthesis (a). Anther dehisces normally (b) and pollen grains are viable (c). (d)–(f) Class 1: the anthers are blue and the pollen grains collected can be seen on the stylar branches (d). Anthers are dehiscent in (e) (arrow head) but pollen viability is reduced (f). (g)–(k) Class 2: the anthers are brown; the pollen grains are not collected as it can be noticed on the stylar branches and the style. In subclass 2a ((h)-(i)) the septum and stomium are disrupted but the opening of locules is not well achieved (arrow head in (h)) and most of pollen grains are not viable (i). In subclass 2b ((j)-(k)) the anthers remain indehiscent and the locule wall is shrunken (arrow head), no lignification of endothecium and connectivum (j) and the pollen grains are not viable (k). (l)–(n) Class 3: the pistil morphology is normal (l), cross section in the mature floret shows that no stamen develops ( in (m)), and longitudinal sections of some florets show some stamen initiation but no differentiation (arrow in (n)). (o)–(q) Class 4: no style is observed (o). The anthers are indehiscent and stacked together (p). Nonviable pollen is shown in (q). (r)–(t) Class 5: no anther and style emerge in the corolla tube ( in (r) and (s)). Longitudinal section of young floret buds shows that stamens and carpels are not initiated ( in (t)). Bars (a), (d), (g), (l), (o), and (r) 2 mm; (b), (e), (h), (j), (m), (n), (p), (s), and (t) 100 μm; (c), (f), (i), (k), and (q) 50 μm.