Female reproductive success decreases with display size in monkshood, Aconitum kusnezoffii (Ranunculaceae).
OBJECTIVE
Reduction in female fitness in large clones can occur as a result of increased geitonogamous self-fertilization and its influence through inbreeding depression. This possibility was investigated in the self-compatible, bee-pollinated perennial herb Aconitum kusnezoffii which varies in clone size.


METHODS
Field investigations were conducted on pollinator behaviour, flowering phenology and variation in seed set. The effects of self-pollination following controlled self- and cross-pollination were also examined. Selfing rates of differently sized clones were assessed using allozyme markers.


RESULTS
High rates of geitonogamous pollination were associated with large display size. Female fitness at the ramet level decreased with clone size. Fruit and seed set under cross-pollination were significantly higher than those under self-pollination. The pre-dispersal inbreeding depression was estimated as 0.502 based on the difference in seed set per flower between self- and cross-pollinated flowers. Selfing rates of differently sized clones did not differ.


CONCLUSIONS
It is concluded that in A. kusnezoffii the negative effects of self-pollination causing reduced female fertility with clone size arise primarily from a strong early-acting inbreeding depression leading to the abortion of selfed embryos prior to seed maturation.
Liao
Wan-Jin
WJ
State Key Laboratory of Earth Surface Processes and Resource Ecology and MOE Key Laboratory for Biodiversity Science and Ecological Engineering, Beijing Normal University, Beijing 100875, China.
Hu
Yi
Y
Zhu
Bi-Ru
BR
Zhao
Xia-Qing
XQ
Zeng
Yan-Fei
YF
Zhang
Da-Yong
DY
D031841:Aconitum / Q000254:growth & development*; D000818:Animals; D001516:Bees; D035264:Flowers / Q000254:growth & development*; D005638:Fruit / Q000254:growth & development*; D007178:Inbreeding; D054817:Pollination