Data for: Drought and temperature stresses impact pollen production and autonomous selfing in a California wildflower, Collinsia heterophylla

Ongoing climatic changes have altered growing conditions for plants by
limiting water availability and inducing unprecedented temperature
increases, eliciting plant functional responses that compromise floral
trait expression, reduce pollen production but promote early
self-pollination. In a controlled greenhouse study, plants of Collinsia
heterophylla, an annual mixed-mated hermaphrodite, were grown under
temperature and water stresses. Floral trait responses and related effects
on plant reproductive success were recorded. Plants grown under
temperature and water stresses were shorter and had fewer leaves at
flowering than control plants. Temperature-stressed plants flowered
earlier and had smaller flowers that produced fewer per capita pollen
grains than control and water-stressed plants. While lifetime flower
production in plants experiencing temperature stress alone or water stress
alone was similar to control plants, those receiving combined temperature
and water stresses had significantly lower lifetime flower production.
Abiotic stress did not affect investment in female traits such as ovule
number per flower but impacted male traits seen as fewer pollen grains per
flower. In plants experiencing abiotic stress, an increase in autonomous
self-pollination was facilitated through a compromise in herkogamy, a
sexual interference mechanism to promote cross-pollination. Spatial
separation between stigma and anther, a measure of herkogamy, was zero or
negative in stressed plants. Thus, abiotic stress responses in plants did
not compromise plant reproductive success as autonomous selfing was
augmented. In nature, such responses will likely reduce available
nutrition for pollinators through decreased flower and pollen production.