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Species Biology of Primula sieboldii for the Conservation of its Lowland‐habitat Population: I. Inter‐clonal Variations in the Flowering Phenology, Pollen Load and Female Fertility Components
Author(s) -
Washitani Izumi,
Namai Hyoji,
Osawa Ryo,
Niwa Masaru
Publication year - 1991
Publication title -
plant species biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.419
H-Index - 36
eISSN - 1442-1984
pISSN - 0913-557X
DOI - 10.1111/j.1442-1984.1991.tb00207.x
Subject(s) - biology , pollen , population , pollinator , botany , pollination , phenology , stamen , germination , achene , ecology , demography , sociology
Intra‐population variations of several characteristics related to fertility were assessed for a nature‐reserve population of Primula sieboldii in the flood plain of the Arakawa River. Although there were large intra‐ and inter‐clonal variations of fruit and seed sets as well as other female fertility components in the 13 clones examined, female fertility was generally low, except in a homomorph clone. Pollinator availability was assessed by continuous monitoring of insect visits with 8 mm film. No insect visits were recorded during the monitoring of total 68 flowers over 16 hours in the nature‐reserve population. In contrast, a high pollinator visitation rate was recorded in a reference population of P. sieboldii on the flank of Mt. Yatugatake. Thus, the low rates of seed production in the nature reserve was due to a shortage of compatible pollens as a result of the limitation of pollinator availability. Stigmas of flowers in various clones occasionally were loaded with pollen grains whose sizes were not significantly different from those of anther pollens of the same flowers. However, pollen germination on stigmas was observed only in the flowers of a homo‐morph clone whose flowers have pin‐type stigmas and anthers with compatible thrum‐type pollens at the same height. Exceptionally high fertility of the homo‐morph clone would be associated with its inbreeding habit.