자료유형  

 학위논문

Control Number  

0017162939

International Standard Book Number  

9798384337362

Dewey Decimal Classification Number  

612

Main Entry-Personal Name  

Fung, Hannah F.

Publication, Distribution, etc. (Imprint  

[S.l.] : Stanford University., 2024

Publication, Distribution, etc. (Imprint  

Ann Arbor : ProQuest Dissertations & Theses, 2024

Physical Description  

148 p.

General Note  

Source: Dissertations Abstracts International, Volume: 86-03, Section: B.

General Note  

Advisor: Bergmann, Dominique;Dinneny, Jose;Red-Horse, Kristy;Wang, Bo.

Dissertation Note  

Thesis (Ph.D.)--Stanford University, 2024.

Summary, Etc.  

요약In plants, stomata are epidermal valves through which carbon dioxide enters and oxygen and water escape. Collectively, stomata are major players in global carbon and water cycles, regulating wateruse efficiency across entire ecosystems. In tropical forests, an estimated 32 x 1015 kilograms of water vapour pass through stomata each year, which is more than double the water vapour cycling through the atmosphere annually (15 x 1015 kg per year; Hetherington and Woodward, 2003).In dicots, stomata comprise a pair of guard cells flanking a central pore. The size of this pore defines the stomatal conductance or the rate at which gases diffuse through the pore. While stomatal conductance varies with environmental conditions, the maximum stomatal conductance is developmentally constrained. This theoretical maximum increases with stomatal number, which is specified during development. To modulate the physiological potential of a leaf, we need to understand how developmental events regulate stomatal number.There are two common measures of stomatal number: stomatal density (the number of stomata per millimeter ) and stomatal index (the proportion of leaf epidermal cells that are stomata). There are several reasons why stomatal index is more informative from a developmental perspective. First, unlike stomatal density, which generally increases from leaf base to tip, stomatal index shows little intra-leaf variation. Second, stomatal index is independent of cell size and is therefore robust to factors that influence cell expansion independently of stomatal number. Finally, stomatal index is a measure of cell type composition, which reflects the division and differentiation events that took place to build the organ.In many species, stomatal index is flexible, increasing with light intensity and decreasing with osmotic stress. Similarly, both short- and long-term studies point to an inverse relationship between carbon dioxide levels and stomatal index. Higher stomatal indices are expected to increase carbon assimilation rates, but at the cost of increased transpiration. What cellular behaviours underlie this developmental flexibility?In this dissertation, I address this question using the model organism, Arabidopsis thaliana,where the stomatal lineage produces the majority of leaf epidermal cells. This lineage begins when a subset of protodermal cells is stochastically selected to become meristemoid mother cells, which divide asymmetrically to produce two daughter cells. The smaller daughter, or the meristemoid, can either differentiate into a stoma or undergo one or more asymmetric divisions before differentiating. The larger daughter, or the stomatal lineage ground cell (SLGC), faces a similar choice: it can either differentiate into a cuticle-producing pavement cell or divide to generate another meristemoid and SLGC.Generally, the stomatal index remains constant when cells differentiate directly. It tends to decrease when meristemoids divide and increase when SLGCs divide. Consequently, the cell type composition of a leaf is regulated by the frequency at which meristemoids and SLGCs divide. In this dissertation, I identify and characterize factors that regulate the frequency of asymmetric cell divisions in the stomatal lineage. I show that cell size influences both meristemoid and SLGC behaviours, but in surprisingly different ways.

Subject Added Entry-Topical Term  

Physiology.

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Embryos.

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Behavior.

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Homeostasis.

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Severe acute respiratory syndrome coronavirus 2.

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Insects.

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Genomes.

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Age groups.

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Biology.

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Metabolism.

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Phosphorylation.

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Apoptosis.

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Stem cells.

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Households.

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Cell cycle.

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Transcription factors.

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Disease transmission.

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Cellular biology.

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Genetics.

Added Entry-Corporate Name  

Stanford University.

Host Item Entry  

Dissertations Abstracts International. 86-03B.

Electronic Location and Access  

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Control Number  

joongbu:657428