Honors Theses

Date of Award

Spring 5-8-2026

Document Type

Undergraduate Thesis

Department

Biology

First Advisor

Yongjian Qiu

Second Advisor

Sayaka Miura

Third Advisor

David Colby

Relational Format

Dissertation/Thesis

Abstract

Ambient temperature strongly influences plant growth and development, and rising global temperatures raise challenges for plant productivity. A well-known response to slightly elevated temperature is thermomorphogenetic root elongation, in which the growth hormone auxin plays a central role. However, the underlying molecular mechanism remains not fully understood. In this study, we investigate whether flavonoids, known modulators of auxin transport, contribute to root thermomorphogenic responses. Using Arabidopsis thaliana as a model, we combined gene expression analysis, DPBA staining, and quercetin treatment approaches to investigate how elevated temperature affects flavonoid biosynthesis and root growth. Seedlings grown at 27 °C exhibited increased primary root length and lateral root number compared with those grown at 20 °C. The expression of several flavonoid biosynthetic genes was reduced under elevated temperature.  Consistent with these findings, DPBA staining revealed reduced flavonoid accumulation in roots at higher temperatures, and exogenous application of quercetin suppressed root elongation. Collectively, these results suggest that elevated temperature reduces flavonoid biosynthesis, potentially relieving inhibition of auxin transport and therefore partially promoting root elongation.

Creative Commons License

Creative Commons Attribution 4.0 International License
This work is licensed under a Creative Commons Attribution 4.0 International License.

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