Low pollination intensity may cause low seed set in plant populations and is thought to be responsible for evolutionary transitions from outcrossing to selfing, or from animal to wind pollination. Variation in pollination intensity may also affect seed quality both through its influence on the degree of pollen competition (with lower quality offspring produced under low pollen intensities) and through seed size–number trade-offs (with plants under low pollination intensity producing fewer but larger seeds).
Here, we use a field experiment to examine the effects of pollination intensity on both quantity and quality of progeny. We manipulated pollen receipt to stigmas of the wind-pollinated dioecious plant Mercurialis annua by varying the distance of females from males. We then compared seed size and number, seedling growth and allocation to male and female function, for the progeny produced by females subjected to different pollination intensities.
Our experiment revealed a reduction in pollen load with increasing distance to males, translating into large reductions in the number of seeds produced but only small effects on the performance of offspring. The main effect on offspring quality was through a seed size–number trade-off, with pollen-limited females producing fewer but larger seeds, which subsequently performed better. Sons and daughters were affected differently by this trade-off, pointing to gender-dependent effects of pollination intensity on progeny performance.
Synthesis. Our results highlight the importance of pollination intensity on both the quantity and quality of progeny. Nevertheless, fitness calculations suggest that the enhanced quality of seed produced by pollen-limited mothers was not sufficient to offset their losses in terms of quantity.
Maternal plant traits
The data result from a field experiment to examine the effects of pollination intensity on both quantity and quality of progeny. We manipulated pollen receipt to stigmas of the wind-pollinated dioecious plant Mercurialis annua by varying the distance of females from males. We then compared seed size and number, seedling growth and allocation to male and female function, for the progeny produced by females subjected to different pollination intensities.
Contact persons:
annemarie.labouche@gmail.com
john.pannell@unil.ch
1) Labouche_et_al_2016_Maternal_plant_traits.txt
Data collected on the maternal plants exposed to different level of pollination intensities.
Definitions of column headings
MotherID:Unique ID of the plant
Mdirection: Directional transect on which the plant was setup
Mdistance: Distance from pollen source of the plant (in meters)
mother_mass: Mass of the dried plant (in g), including reproductive seeds
mother_total_seed_mass: Mass of the seeds produced by the plant (in g)
mother_veg_mass: Mass of the dried plant (in g) without reproductive parts
mother_seed_number: Number of seeds produced by the plant (count)
Labouche_et_al_2016_Maternal_plant_traits.txt
Offspring traits
The data result from a field experiment to examine the effects of pollination intensity on both quantity and quality of progeny. We manipulated pollen receipt to stigmas of the wind-pollinated dioecious plant Mercurialis annua by varying the distance of females from males. We then compared seed size and number, seedling growth and allocation to male and female function, for the progeny produced by females subjected to different pollination intensities.
Contact persons:
annemarie.labouche@gmail.com
john.pannell@unil.ch
2) Labouche_et_al_2016_Offspring_traits.txt
Data collected on the seeds and resulting offspring produced by the maternal plants exposed to different level of pollination intensities.
Definitions of column headings
seedID: Unique ID of the seed
Mdirection: Directional transect on which the maternal plant was setup
Mdistance: Distance from pollen source of the maternal plant (in meters)
motherID: Unique ID of the maternal plant
Mpollination: Pollination intensity treatment of the maternal plant; h=high (0.2 and 0.5m from males); l=low (20 and 25 m from males)
seedmass: mass of the individual seed (in mg)
seedcat: mass categories of the offspring as seed: A <2; 2<=B<2.49; 2.54
germ: germination status of the seed (0=not germinated; 1=germinated)
time-germ: number of days between sowing and full expansion of the cotyledons
offspringID: Unique ID of the offspring (for germinated seeds)
plotID: ID of the plot in which the seedling grew once in the common garden; ID range from 1 to 54, with 16 positions per plot
position: Position of the offspring within its plot (ranges from 1 to 16)
treatment: whether the offspring was growing with a competitor (hermaphrodite) or not. If the competitor survived (treatment = I), if it died due to transplantation issues (treatment =I0); if the offspring grew alone (treatment = C).
offspring_sex: Sex of the offspring (M=male; F=female)
offspring_survival: 1= the offspring was still alive at the end of the experiment; 0= the offspring died in the course of the experiment
offspring_height: Height of the offspring (in cm) on the day of harvesting
offspring_mass: Mass of the dried offspring (in g), including reproductive parts (seeds for females)
offspring_veg_mass: Mass of the dried offspring (in g) without reproductive parts
offspring_total_seed_mass: Mass of the seeds produced by the offspring (in g)
offspring_seed_number: Number of seeds produced by the offspring (count)
offspring_male_allocation: Mass of male inflorescences (inflorescences stems + dried flowers) in mg
Labouche_et_al_2016_Offspring_traits.txt