PS 26-73 - CANCELLED - The effects of drought stress on flower features of a buzz pollinated species

Background/Question/Methods

Climate change manifests itself in extreme events such as severe drought, floods and heatwaves. Such events can severely impact plant reproductive success and fitness either by impairing floral physiological processes or disrupting plant-pollinator networks. Drought or reduced water availability has been a predominant concern in both cropland and natural tropical ecosystems. While negative impacts on yield have been shown, the array of mechanisms that are used to cope or respond to drought conditions is little known in animal pollinated species. In this study, we simulated mild and moderate drought conditions in a greenhouse experiment and examined the impact of such conditions on floral traits of a buzz pollinated species. We also investigated the extent of intraspecific variation exhibited in these different conditions. Buzz pollinated plants form one such group of angiosperms, offering nutrient-rich pollen and reliant on specialized bee pollinators capable of producing thoracic vibrations required to eject pollen from tube-like poricidal anthers. They represent about 20,000 species of angiosperms, most of which have specialized anthers called poricidal anthers and include various economically essential crops. We hypothesized that moderate or severe drought would increase investment in reproductive traits and display as early and intense flower production compared to other conditions.

Results/Conclusions

We found that the control plants produced more flowers than the drought plants. Of the 13 floral morphological characteristics measured, we found petal length, petal width, and flower diameter to be greater in control plants than in drought plants. Plants in the two drought conditions exhibited different responses; those that experienced mild drought produced fewer and smaller flowers than those subjected to moderate drought. While there was considerable variation between individuals and decreased flowering in drought plants, our results suggest a substantial reproductive investment in the drought condition plants. Our analysis with a few other reproductive features, such as pollen production and quality, is ongoing. Overall, our study will provide valuable insights into responses of plant species and their reproductive fitness in the context of rapidly changing climatic conditions.