Abstract Detail

Ecological Section

Arathi H.S., Arathi [1], Rachael, Jorgensen [1].

Can variable expression of herkogamy under drought stress explain autonomous selfing rates in Collinsia heterophylla?

Mixed-mating systems are commonplace in flowering plants, but what prevents these from becoming obligate selfed or out-crossed species is a question of interest especially in those where selfing does not result in serious inbreeding depression. In such species with little or no inbreeding depression, it may be reasonable to assume that autonomous selfing may be modulated by factors such as abiotic stressors that impose high costs in terms of resources available for reproduction. Little is however known about the timing and mechanism of selfing in relation to abiotic stress. In order to understand autonomous selfing rates under drought stress, plants of Collinsia heterophylla were grown under low, medium and high soil water levels. Drought stressed plants flowered significantly earlier and differed in total number of flowers produced over the plant lifespan. There were also significant differences in herkogamy levels, timing of anther and stigma maturation, pollen viability and seed set between individuals from the three treatments. Plants experiencing drought-stress can be expected to reduce their floral lifespan in order to minimize water loss through floral organs. Under such conditions of reduced floral longevity, autonomous selfing via reduced herkogamy could be a mechanism to produce progeny. If a reduction in herkogamy results in increased selfing rates, it could also lead to early flower abscission and reduce moisture loss through open flowers. Acute resource stress may thus result in the alteration of the prevalent mating-system via the modulation of floral mechanisms.

Broader Impacts:

1 - Colorado State University, Biology, 1878 Biology, Fort Collins, CO, 80523, USA

Keywords:
herkogamy
drought stress
selfing rate
Collinsia heterophylla.

Presentation Type: Oral Paper:Papers for Sections
Session: 33
Location: 555B/Convention Center
Date: Tuesday, August 3rd, 2010
Time: 10:45 AM
Number: 33003
Abstract ID:585