PHYSIOLOGICAL AND BIOCHEMICAL ADAPTATIONS IN SOME CAM SPECIES UNDER NATURAL CONDITIONS: THE IMPORTANCE OF LEAF ANATOMY

Bibliographic Details
Main Author:	Fondom, Nicolas Yebit
Language:	English
Published:	Miami University / OhioLINK 2009
Subjects:	Agriculture Agronomy Anatomy and Physiology Biology Botany Crassulacean acid metabolism (CAM) Peperomia obtusifolia Peperomia macrostachya Agave striata Leaf anatomy Anthocyanins Xanthophyll-cycle Chlorophyll a fluorescence Gas exchange Carbon balance
Online Access:	http://rave.ohiolink.edu/etdc/view?acc_num=miami1260552594

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spelling	ndltd-OhioLink-oai-etd.ohiolink.edu-miami12605525942021-08-03T05:40:48Z PHYSIOLOGICAL AND BIOCHEMICAL ADAPTATIONS IN SOME CAM SPECIES UNDER NATURAL CONDITIONS: THE IMPORTANCE OF LEAF ANATOMY Fondom, Nicolas Yebit Agriculture Agronomy Anatomy and Physiology Biology Botany Crassulacean acid metabolism (CAM) Peperomia obtusifolia Peperomia macrostachya Agave striata Leaf anatomy Anthocyanins Xanthophyll-cycle Chlorophyll a fluorescence Gas exchange Carbon balance <p>This dissertation consists of an introduction and three independent research chapters. Chapter one (introduction) presents a review of CAM (Crassulacean Acid Metabolism) biology, chlorophyll fluorescence, and leaf optical properties. Chapter two addresses the physiology, anatomy, and biochemistry of two tropical <i>Peperomia</i> species in the field in the El Cielo Biosphere Reserve in Tamaulipas, Mexico. Chapters three and four address similar studies in two morphs of <i>Agave striata</i> (red vs. green leaves) under natural condition in the high plateau desert region of Miquihuana, Tamaulipas, Mexico. The summary for each of the research chapters is discussed.</p><p>In chapter two, I tested, under field conditions, the hypotheses that relative thickness of the spongy mesophyll layer is an indication of CAM and that water distribution within the leaf tissues of the two <i>Peperomia</i> species studied changes differently in response to drought. The results showed that when well-watered, <i>P. obtusifolia</i> has typical C3-activity and <i>P. macrostachya</i> has typical CAM-activity, with spongy mesophyll layer thickness of 26% and 76% respectively. In addition, the results also showed that the distribution of water in the leaf tissue in <i>P. obtusifolia</i> changes in response to drought, from the hydrenchyma to the chlorenchyma, but this is not the case in <i>P. macrostachya</i>.</p> <p>In chapter three, I tested the hypothesis that leaf epidermal pigments screen light of particular wavelengths from reaching the photosynthetic machinery, reducing dependence on the xanthophyll cycle as an energy dissipation process in two morphs of <i>Agave striata</i> (red vs. green leaves). The results showed that Fo (dark level fluorescence), Fv/Fm (maximum PSII efficiency), and ΦPSII (quantum yield of PSII) were higher under sun in leaves of the red morph compared to the green morph. Leaf surface temperature, xanthophyll conversion, and qN (non-photochemical quenching) were significantly higher during the day for leaves of the green morph compared to the red morph. From these results, it is clear that the sub-epidermal anthocyanins serve as a photoprotective barrier in the leaves of the red morph.</p> <p>Finally, in chapter four, the first goal of this project was to test the hypothesis that leaf wax development is a delayed response to sunlight exposure following cutin development. The second goal of this project tested the hypothesis that during leaf ontogeny in the two morphs of <i>A. striata</i>, energy dissipation shifts from non-photochemical to photochemical quenching. The results showed that on both the adaxial and abaxial leaf surfaces of young and mature leaves of both morphs, leaf wax thickness increased from the basal end of the leaf whereas cutin thickness decreased from the basal end of the leaf. Thus, as leaf age in both morphs of <i>A. striata</i>, cutin deposition exceeds wax deposition at the early stages of development. Furthermore, chlorophyll fluorescence data supported the photoprotective function of anthocyanin, indicating that the deposition of anthocyanins may help to reduce dependence of the leaf on energy dissipation via the xanthophyll cycle and non-photochemical quenching during leaf ontogeny.</p> 2009-12-14 English text Miami University / OhioLINK http://rave.ohiolink.edu/etdc/view?acc_num=miami1260552594 http://rave.ohiolink.edu/etdc/view?acc_num=miami1260552594 unrestricted This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws.
collection	NDLTD
language	English
sources	NDLTD
topic	Agriculture Agronomy Anatomy and Physiology Biology Botany Crassulacean acid metabolism (CAM) Peperomia obtusifolia Peperomia macrostachya Agave striata Leaf anatomy Anthocyanins Xanthophyll-cycle Chlorophyll a fluorescence Gas exchange Carbon balance
spellingShingle	Agriculture Agronomy Anatomy and Physiology Biology Botany Crassulacean acid metabolism (CAM) Peperomia obtusifolia Peperomia macrostachya Agave striata Leaf anatomy Anthocyanins Xanthophyll-cycle Chlorophyll a fluorescence Gas exchange Carbon balance Fondom, Nicolas Yebit PHYSIOLOGICAL AND BIOCHEMICAL ADAPTATIONS IN SOME CAM SPECIES UNDER NATURAL CONDITIONS: THE IMPORTANCE OF LEAF ANATOMY
author	Fondom, Nicolas Yebit
author_facet	Fondom, Nicolas Yebit
author_sort	Fondom, Nicolas Yebit
title	PHYSIOLOGICAL AND BIOCHEMICAL ADAPTATIONS IN SOME CAM SPECIES UNDER NATURAL CONDITIONS: THE IMPORTANCE OF LEAF ANATOMY
title_short	PHYSIOLOGICAL AND BIOCHEMICAL ADAPTATIONS IN SOME CAM SPECIES UNDER NATURAL CONDITIONS: THE IMPORTANCE OF LEAF ANATOMY
title_full	PHYSIOLOGICAL AND BIOCHEMICAL ADAPTATIONS IN SOME CAM SPECIES UNDER NATURAL CONDITIONS: THE IMPORTANCE OF LEAF ANATOMY
title_fullStr	PHYSIOLOGICAL AND BIOCHEMICAL ADAPTATIONS IN SOME CAM SPECIES UNDER NATURAL CONDITIONS: THE IMPORTANCE OF LEAF ANATOMY
title_full_unstemmed	PHYSIOLOGICAL AND BIOCHEMICAL ADAPTATIONS IN SOME CAM SPECIES UNDER NATURAL CONDITIONS: THE IMPORTANCE OF LEAF ANATOMY
title_sort	physiological and biochemical adaptations in some cam species under natural conditions: the importance of leaf anatomy
publisher	Miami University / OhioLINK
publishDate	2009
url	http://rave.ohiolink.edu/etdc/view?acc_num=miami1260552594
work_keys_str_mv	AT fondomnicolasyebit physiologicalandbiochemicaladaptationsinsomecamspeciesundernaturalconditionstheimportanceofleafanatomy
_version_	1719423510129934336

PHYSIOLOGICAL AND BIOCHEMICAL ADAPTATIONS IN SOME CAM SPECIES UNDER NATURAL CONDITIONS: THE IMPORTANCE OF LEAF ANATOMY

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