Abstract Detail

Ecology

Höfer, Rebecca [1], Ayasse, Manfred [1], Kuppler, Jonas [1].

Effects of water stress on floral scent, morphology and reproductive success.

Reduced precipitation and drought events can alter floral traits with cascading effects on flower-visitor interactions and plant fitness. However, the interplay of magnitudes of water stress on floral traits, especially scent and flower-visitor interactions and reproductive success are poorly understood. In a field experiment, we tested how reduced mean precipitation and prolonged dry periods affect floral scent bouquet, morphology, phenology, flower-visitor interactions and seed set. Plant individuals of multiple mother plants of Sinapis arvensis were randomly assigned to either of three treatments: mean precipitation (=control), reduced mean precipitation and drought treatment. Individuals were planted under five rain-out shelters, in which each shelter served as a replicate. Plants in the precipitation treatments were watered daily using a drip irrigation system, whereas plants in the drought treatment were only watered when they showed severe signs of wilting. Flower-visitor interactions were recorded on non-rainy days. An interaction was defined as a visit by an arthropod on one or more flowers of one plant individual; that is a single flower visitor that visited several flowers of one plant individual consecutively was regarded as one interaction. We found that the effects on floral traits were dependent on the strength of water stress – measured as leaf water potential – with increasing stress resulting in e.g., smaller growth and lower number of flowers. However, total scent emission per flower was not affected by water stress and plants were able to maintain scent bouquets and flower-visitor interactions, what retained the pollination success of the existing flowers. Nevertheless, as water stress reduced the number of flowers, which in turn led to fewer siliques and ultimately reduced seed set, we could show that water stress indirectly reduces plants’ reproductive success.

1 - Ulm University, Institute of Evolutionary Ecology and Conservation Genomics, Albert-Einstein-Allee 11, Ulm, BW, 89081, Germany

Keywords:
Brassicaceae
climate change
Drought
floral traits
plant-pollinator interactions.

Presentation Type: Oral Paper
Session: ECO5, Ecology: Stress
Location: /
Date: Thursday, July 22nd, 2021
Time: 2:00 PM(EDT)
Number: ECO5007
Abstract ID:344
Candidate for Awards:None