TY  - JOUR
A1  - Lumaga, Maria Rosaria Barone
A1  - Cozzolino, Salvatore
A1  - Kocyan, Alexander
A1  - Menale, Bruno
A1  - Rudall, Paula J.
T1  - Exine micromorphology and ultrastructure in Neottieae (Epidendroideae, Orchidaceae)
JF  - Plant systematics and evolution
N2  - The diverse epidendroid orchid tribe Neottieae is characterized by multiple transitions between autotrophy and mycoheterotrophy, allogamous and autogamous mating systems, pollen released as tetrads or monads, and pollen exine tectate or semitectate. We use transmission and scanning electron microscopy on pollen of ten species of Neottieae to investigate whether the differences in pollen aggregation and exine micromorphology and ultrastructure reflect phylogenetic relationships, or whether this variation is subject to ecological constraints. Our results showed that differences in exine micromorphology are mostly concordant with phylogenetic relationships in Neottieae, i.e. an ascending tendency of pollen ornamentation from tectate (Cephalanthera) to semitectate (e.g. Neottia). In contrast, pollen aggregation, when plotted on the most recent phylogeny, shows repeated transitions between monads and tetrads that could be related to ecological constraints. Tetrads are present in species that are nectar rewarding, whereas monads are common in deceptive species. Cephalanthera is characterized by recalcitrant pollen, including the frequent occurrence of collapsed pollen. In this genus, the observed shifts from allogamous to autogamous or cleistogamous mating systems could help to reduce pollen damage caused by exposure to dry habitats.
KW  - Mating system
KW  - Monads
KW  - Neottieae
KW  - Pollenkitt
KW  - Tetrads
KW  - Ulcerate pollen
Y1  - 2014
U6  - https://doi.org/10.1007/s00606-013-0899-2
SN  - 0378-2697
SN  - 1615-6110
VL  - 300
IS  - 3
SP  - 505
EP  - 515
PB  - Springer
CY  - Wien
ER  -