Mating System Evolution: Correlations between Seed Set and - - PowerPoint PPT Presentation

Mating System Evolution: Correlations between Seed Set and Physiological rates

By: Anthony Linarez Principal Investigator: Susan J. Mazer Post Doctorate Mentor: Leah Dudley Department of Ecology, Evolution & Marine Biology University of California, Santa Barbara

Ma ting Syste m

• Outcrossing
• Vector needed
• Great genetic diversity
• Ability to adapt
• Self-fertilization
• No vector needed
• Low genetic diversity
• Inability to adapt
• extinction

Hypo the se s

Selfing evolved from outcrossing species

• Reproductive assurance hypothesis
• Drought avoidance hypothesis

Why does Selfing persist?

• Counterintuitive
• Long-term problems

Question: Is fitness correlated with drought avoidant traits?

Whe n Se lfe rs E vo lve

fitness fitness Drought Avoidance Trait 1 Drought Avoidance Trait 2

If trends exist then selfers will have evolved from

• utcrossers on the high fitness spectrum.

Dro ug ht Avo ida nc e

Photosynthesis Transpiration Water Use Efficiency Carbon Gain Water Loss Carbon Gain Water Loss Higher rates Positively correlated with fitness Higher Rates Positively correlated with fitness ?

Se e d Se t

How you measure: Percentage: Mature seeds Mature seeds + aborted ovules Definition: A measure of plant fitness. Corresponds to the actual number of mature seeds compared to seed potential.

Mature Seeds Aborted ovules

Study Site : Sawmill

• Seasonal Temperatures
• Extreme edge of habitat
• Hot and dry region
• Clarkia xantiana ssp xantiana
• Sympatric with selfing sister

taxon: xantiana ssp parviflora

Pro je c t Go a ls

What will be done in lab:

• Measure Seed set in plants collected in field
• Correct physiological data taken in the field

using leaf area

• Correlate physiological rates to seed set
• Correlating physiological rates with fitness
• Looking for general patterns in outcrossing species

E xpe rime nta l Me tho ds: Physio lo g ic a l ra te s

An infrared gas exchange analyzer was used to measure:

Photosynthesis Transpiration Measures the CO2 taken in and H2O given off

Collected measured leaves

Measure area of leaves analyzed in IRGA

Infrared gas analyzer

E xpe rime nt Me tho ds: Se e d se t

In the Field: Glued fruits shut with silicon Collected plants after all fruits matured In the Lab: Separate fruits from stem Open fruits Separate mature seeds from aborted ovules Count mature seed and aborted ovules

Aborted ovules Mature seeds underdeveloped

Re sults: Pho to synthe sis

Photosynthetic Rate (umol CO2 m-2 s-1) Seed Set

0.2 0.4 0.6 0.8 1

10 20 30 40 50 60

y=0.82-.0016x R2=0.03 P=0.3

Re sults: T ra nspira tio n

Loge Transpiration (umol H2O m-2 s-1) Seed Set

0.2 0.4 0.6 0.8 1

• 8
• 6
• 4
• 2

y=0.67-0.02x R2=.018 P=0.42

Re sults: Wate r Use E ffic ie nc y

0.2 0.4 0.6 0.8 1

• 2.5
• 2
• 1.5
• 1
• 0.5

Seed Set Loge WUE (umol CO2/umol H2O)

y=0.77+0.0006x R2=0.000008 P=0.98

Ana lysis

What patterns are present between outcrossing species?

There is no correlation between seed set and physiology

Only one population of a data Preflowering vs. Flowering

The Next Step:

Analyze more data from different populations and species Account for flowering stage Take out other effects, such as biomass.

Ac kno wle dg e me nts

• Susan Mazer
• Leah Dudley
• Alisa Hove
• Ofelia Aguirre
• Eric Pressly
• NSF
• CNSI
• UCSB
• UC Leads