Exploring Seasonal Flowering Mechanisms

University Of Washington, Seattle WA

Investigators

Abstract

The proper timing of flowering affects not only successful fertilization and seed output, but also efficiency of germination and plant growth for the next generation. Crop yields are particularly vulnerable to a changing climate, as flowering time is strongly regulated by external temperature as well as the light environment. It is of great interest to understand the mechanisms governing flowering time in natural conditions to improve the performance of crops. Many plants, including major crops, utilize changes in day length to adjust the timing of flowering over the seasons, as these changes occur in a more predictable manner than other environmental changes. The mechanisms of day length-controlled flowering have been most characterized in Arabidopsis, the genetic model plant. Because flowering time is controlled in many plants by common mechanisms, the knowledge obtained from Arabidopsis has accelerated the research on flowering time being carried out on all major crops, as well as the research on plants commercially important for agriculture, horticulture and forestry. In the lab, simplified research conditions with few variables make it easier to more accurately analyze results, but these conditions may not precisely reflect what happens in nature. By adjusting several critical environmental parameters (such as light and temperature) of the current standard lab conditions to more closely reflect natural settings, this project will provide a more accurate understanding of the mechanisms of seasonal flowering. This project will also nurture interdisciplinary training for a postdoctoral researcher, a graduate student, and undergraduate students, and support the involvement of ethnic minorities and women in science. Flowering is induced by largely conserved mechanisms in angiosperms. In Arabidopsis, the key mechanism is the way in which light and the circadian clock regulate the expression of the master flowering gene, FLOWERING LOCUS T (FT). Preliminary results indicate that our current understanding of day length-dependent flowering regulation is not sufficient to explain the regulatory mechanism of plants grown under natural long-day conditions. In plants grown outside near the time of the summer solstice, FT expression patterns differed from those in plants grown in long-day conditions in the lab. This is likely caused by the differences in light quality and temperature between those conditions. This project aims to more precisely examine the combinatorial effects of daily light and temperature changes on flowering time at the physiological, biochemical and molecular levels. The knowledge obtained will provide a mechanistic insight into seasonal flowering events happening at present in nature and provide clues that will help us predict flowering phenology in rapidly changing climates. The information regarding improved lab growth conditions that more closely reflect natural conditions will be disseminated to members of the research community to help improve their research. In addition, the related video outreach activity will generate teaching tools for high school science classes, and also provide videos that depict dynamic developmental changes in plants for the general public.