Show simple item record

dc.contributor.advisorMoran, Mary Susanen_US
dc.contributor.advisorPapuga, Shirley Anneen_US
dc.contributor.authorCendrero Mateo, Maria del Pilar
dc.creatorCendrero Mateo, Maria del Pilaren_US
dc.date.accessioned2014-02-10T22:41:12Z
dc.date.available2014-02-10T22:41:12Z
dc.date.issued2013
dc.identifier.urihttp://hdl.handle.net/10150/312504
dc.description.abstractThe increasing food demand as well as the need to predict the impact of warming climate on vegetation makes it critical to find the best tools to assess crop production and carbon dioxide (CO₂) exchange between the land and atmosphere. Photosynthesis is a good indicator of crop production and CO₂ exchange. Chlorophyll fluorescence (ChF) is directly related to photosynthesis. ChF can be measured at leaf-scale using active techniques and at field-scales using passive techniques. The measurement principles of both techniques are different. In this study, three overarching questions about ChF were addressed: Q1) How water, nutrient and ambient light conditions determine the relationships between photosynthesis and ChF? Which is the optimum irradiance level for detecting water and nutrient deficit conditions with ChF?; Q2) which are the limits within which active and passive techniques are comparable?; and Q3) What is the seasonal relationship between photosynthesis and ChF when nitrogen is the limiting factor? To address these questions, two main experiments were conducted: Exp1) Concurrent photosynthesis and ChF light-response curves were measured in camelina and wheat plants growing under (i) intermediate-light and (ii) high-light conditions respectively. Plant stress was induced by (i) withdrawing water, and (ii) applying different nitrogen levels; and Exp2) coincident active and passive ChF measurements were made in a wheat field under different nitrogen treatments. The results indicated ChF has a direct relationship with photosynthesis when water or nitrogen drives the relationship. This study demonstrates that the light level at which plants were grown was optimum for detecting water and nutrient deficit with ChF. Also, the results showed that for leaf-average-values, active measurements can be used to better understand the daily and seasonal behavior of passive ChF. Further, the seasonal relation between photosynthesis and ChF with nitrogen stress was not a simple linear function. Our study showed that at times in the season when nitrogen was sufficient and photosynthesis was highest, ChF decreased because these two processes compete for available energy. These results demonstrated that ChF is a reliable indicator of crop stress and has great potential for better understand the CO₂ exchange between the land and atmosphere.
dc.language.isoen_USen
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.subjectNitrogenen_US
dc.subjectNon-photochemical quenchingen_US
dc.subjectPhotosynthesisen_US
dc.subjectWateren_US
dc.subjectSoil, Water & Environmental Scienceen_US
dc.subjectFluorescenceen_US
dc.titleChlorophyll Fluorescence Response to Water and Nitrogen Deficiten_US
dc.typetexten
dc.typeElectronic Dissertationen
thesis.degree.grantorUniversity of Arizonaen_US
thesis.degree.leveldoctoralen_US
dc.contributor.committeememberMoran, Mary Susanen_US
dc.contributor.committeememberPapuga, Shirley Anneen_US
dc.contributor.committeemembervan Leeuwen, Willemen_US
dc.contributor.committeememberMonson, Russell K.en_US
dc.contributor.committeememberThorp, Kellyen_US
dc.contributor.committeememberMoreno, Joseen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.disciplineSoil, Water & Environmental Scienceen_US
thesis.degree.namePh.D.en_US
refterms.dateFOA2018-06-15T22:03:54Z
html.description.abstractThe increasing food demand as well as the need to predict the impact of warming climate on vegetation makes it critical to find the best tools to assess crop production and carbon dioxide (CO₂) exchange between the land and atmosphere. Photosynthesis is a good indicator of crop production and CO₂ exchange. Chlorophyll fluorescence (ChF) is directly related to photosynthesis. ChF can be measured at leaf-scale using active techniques and at field-scales using passive techniques. The measurement principles of both techniques are different. In this study, three overarching questions about ChF were addressed: Q1) How water, nutrient and ambient light conditions determine the relationships between photosynthesis and ChF? Which is the optimum irradiance level for detecting water and nutrient deficit conditions with ChF?; Q2) which are the limits within which active and passive techniques are comparable?; and Q3) What is the seasonal relationship between photosynthesis and ChF when nitrogen is the limiting factor? To address these questions, two main experiments were conducted: Exp1) Concurrent photosynthesis and ChF light-response curves were measured in camelina and wheat plants growing under (i) intermediate-light and (ii) high-light conditions respectively. Plant stress was induced by (i) withdrawing water, and (ii) applying different nitrogen levels; and Exp2) coincident active and passive ChF measurements were made in a wheat field under different nitrogen treatments. The results indicated ChF has a direct relationship with photosynthesis when water or nitrogen drives the relationship. This study demonstrates that the light level at which plants were grown was optimum for detecting water and nutrient deficit with ChF. Also, the results showed that for leaf-average-values, active measurements can be used to better understand the daily and seasonal behavior of passive ChF. Further, the seasonal relation between photosynthesis and ChF with nitrogen stress was not a simple linear function. Our study showed that at times in the season when nitrogen was sufficient and photosynthesis was highest, ChF decreased because these two processes compete for available energy. These results demonstrated that ChF is a reliable indicator of crop stress and has great potential for better understand the CO₂ exchange between the land and atmosphere.


Files in this item

Thumbnail
Name:
azu_etd_13147_sip1_m.pdf
Size:
2.520Mb
Format:
PDF

This item appears in the following Collection(s)

Show simple item record