Identification of pre-fertilization reproductive barriers and the underlying cytological mechanism in crosses among three petal-types of Jasminum sambac and their relevance to phylogenetic relationships
Fig 8
Electron micrographs of stigmas and styles of the double-petal (DP) jasmine plants.
(a–c) Stigmas sampled from partially opened flowers (i.e., Stage 2). (a) Multi-cellular section exhibiting the ultrastructural characteristics. Several starch granules were observed in each chloroplast. (b) Enlarged graph of (a) showing a single chloroplast with starch granules. (c) Enlargement of the chloroplast showing the grana and lamellae (arrow heads). (d–e) Styles sampled at Stage 2. (d) Multi-cellular section exhibiting the ultrastructural characteristics. Note several starch granules in each chloroplast. (e) The transfer cell. (f–h) Stigmas sampled from fully opened flowers (i.e., Stage 3). (f) Multi-cellular section exhibiting the ultrastructural characteristics. Note starch granules were not observed although chloroplasts still existed. (g) Enlarged graph of (f) showing several chloroplasts. (h) Enlargement of a chloroplast showing the grana and lamellae. (i–j) Styles sampled at Stage 3. (i) Multi-cellular section exhibiting the ultrastructural characteristics. (j) Enlarged graph of (i) showing a chloroplast. Notice the grana and lamellae were empty and fewer than normal. (k–m) Stigmas sampled from flowers at one day post fully opened (i.e., Stage 4). (k) Multi-cellular section exhibiting the ultrastructural characteristics. Notice the shape of cells was irregular. (l) Enlarged graph of (k) showing the cellular organelles. (m) A single chloroplast with flaccid grana and lamellae (arrow heads). (n–o) Styles sampled at Stage 4. (n) Multi-cellular section exhibiting the ultrastructural characteristics. Notice the cells had degenerated, and the organelles were fuzzy and unclear. (o) A degraded chloroplast. Notice the plasmolysis (arrow heads) occurred and sized cavities had formed. Abbreviations: Ch, chloroplast; CW, cell wall; Mi, mitochondria; SG, starch granule