In the continental United States, mean surface air temperature is expected to increase by up to 5°C within 100 years. With hotter temperatures, leaf budbreak is expected to occur earlier in forests, and leaf area is expected to increase in locations where temperature is limiting. The response of plant photosynthesis to hotter temperatures is less certain; plant productivity could increase or decrease. Past studies have found intraspecific variation in the responses of forest tree productivity, phenology, canopy leaf area, and leaf isoprene emission to warming, which all influence carbon uptake and yield for agricultural tree species; it is therefore important to understand not only how hot climates affect carbon uptake and biomass production between different tree species, but also in different genotypes of the same species. We conducted a common garden study at the Biosphere 2 research center near Oracle, AZ, USA. We created a hybrid poplar plantation of 168 trees, which were planted as cuttings in January 2013. The trees used in this study are comprised of 5 distinct genotypes of Populus deltoides × trichocarpa from a range of average annual air temperatures. We measured photosynthetic capacity, leaf phenological timing, canopy leaf area and aboveground woody biomass in 2014 growing season, and leaf isoprene emission in the 2015 growing season. We observed a strong effect of genotype on aboveground woody biomass increment, implying strong local adaptation to the home range and limited phenotypic plasticity in terms of physiological and biometric responses to high temperature environments. Our study suggests that genotypes from hotter home ranges are able to maintain photosynthetic capacity and canopy leaf area late into the growing season, despite high temperatures, and thus produce more aboveground woody biomass. This study may have implications for agricultural management—as temperatures warm where managers currently grow hybrid poplar for agricultural or other purposes, the genotypes from those home ranges would likely have reduced yield; managers could investigate the use of genotypes from home ranges with higher average temperatures to replace the vulnerable local varieties.

Woody plant expansion has been documented for decades in many different ecosystems, often due to anthropogenic disturbances to the environment and yielding vast changes in ecosystem functioning. While causes and consequences of woody expansion have been well documented, few studies have investigated functional traits of woody species that promote rapid expansion in range. My objective was to determine if hydraulic efficiency confers enhanced photosynthetic efficiency so that functional traits representing light and water use may be possible mechanisms facilitating woody encroachment into grasslands and forest understories. I quantified leaf-level light environment, photosynthetic activity, and hydraulic characteristics of three sympatric broadleaf evergreens of varying leaf life span (Ilex opaca, Kalmia latifolia, and Myrica cerifera) in a deciduous forest understory to understand seasonal intra- and interspecific ranges of broadleaf evergreen physiology. Additionally, I investigated the effects of age on physiological efficiency of M. cerifera across a chronosequence (i.e., space for time substitution) of shrub thicket development in order to understand possible age-related physiological mechanisms facilitating shrub expansion. Lastly, I determined functional traits and resulting physiology that contribute to rapid expansion and thicket formation of an invasive, deciduous, N-fixing shrub, Elaeagnus umbellata, and a native, evergreen, N-fixing shrub M. cerifera. When compared to co-occurring evergreen species, electron transport rate (ETR) of M. cerifera was nearly double that of I. opaca or K. latifolia in summer. Photosynthetic capacity was positively related to hydraulic capacity among understory evergreens. Furthermore, photosynthetic and hydraulic efficiency of M. cerifera remained consistent despite considerable differences in thicket age and development. Both similar and contrasting functional traits of E. umbellata and M. cerifera allowed for enhanced light capture and water movement, and reductions in subcanopy light penetration. Enhanced hydraulic and photosynthetic efficiency relative to co-occurring species contributes to rapid range expansion and thicket formation by promoting enhanced productivity and limiting successful colonization of other species. My results indicate that there may be suites of functional traits linked to expansive success and thicket-formation, yet differences in functional traits between native and invasive species represent alternative strategies leading to rapid growth and thicketization.

No description available.

Eddy-covariance (EC) CO₂ flux data were analysed and annual carbon (C) balances estimated for a four-year period (2004-2007) following clearcut harvesting of a boreal jack pine stand in northern Saskatchewan. The site was a source of C to the atmosphere for all years, with annual net ecosystem productivity (NEP) increasing from -153 g C m⁻² yr⁻¹ in 2004 to -63 g C m⁻² yr⁻¹ in 2007. This increase was mainly due to gross primary productivity (GPP) increasing significantly from 78 to 200 g C m⁻² yr⁻¹ , while ecosystem respiration (R) increased only slightly from 231 to 263 g C m⁻² yr⁻¹ over the same period. In the 2006 growing season (GS), a field campaign was conducted to investigate the relationships between monthly destructive measurements of leaf area index (LAI) and daily measurements of the normalized difference vegetation index (NDVI) and photosynthetic capacity (Amax). The latter was derived from 5-day, 16-day, 30-day and annual Michaelis-Menten light response analyses using daytime measurements of NEP and incident photosynthetically active radiation. Digital-camera data were used to evaluate the potential of using the rectilinear-lens vegetation index (RLVI) as a surrogate for NDVI of a young forest stand. Results showed that LAI was linearly related to NDVI and RLVI, which was largely the result of changes in the deciduous vegetation component across the GS. These results indicate that RLVI could be used as a surrogate for NDVI up to a GS maximum LAI of 0.91 m2 m⁻² observed in 2006. Measured mean (± 1 S.D.) GS LAI was 0.67 (± 0.24) m² m⁻² in 2006. LAI accounted for the majority of the variability in Amax at the 30-day time scale, while at shorter time scales air temperature was the dominant control. For 2004 to 2007, mean spring estimates of LAI were 0.25, 0.29, 0.38 (compared to 0.40 m² m⁻² from measurements) and 0.41 m² m⁻², respectively. Results suggest that a steady increase in the jack pine LAI component accounted for the annual increases in GPP and hence NEP over the four years.

Eddy-covariance (EC) CO₂ flux data were analysed and annual carbon (C) balances estimated for a four-year period (2004-2007) following clearcut harvesting of a boreal jack pine stand in northern Saskatchewan. The site was a source of C to the atmosphere for all years, with annual net ecosystem productivity (NEP) increasing from -153 g C m⁻² yr⁻¹ in 2004 to -63 g C m⁻² yr⁻¹ in 2007. This increase was mainly due to gross primary productivity (GPP) increasing significantly from 78 to 200 g C m⁻² yr⁻¹ , while ecosystem respiration (R) increased only slightly from 231 to 263 g C m⁻² yr⁻¹ over the same period. In the 2006 growing season (GS), a field campaign was conducted to investigate the relationships between monthly destructive measurements of leaf area index (LAI) and daily measurements of the normalized difference vegetation index (NDVI) and photosynthetic capacity (Amax). The latter was derived from 5-day, 16-day, 30-day and annual Michaelis-Menten light response analyses using daytime measurements of NEP and incident photosynthetically active radiation. Digital-camera data were used to evaluate the potential of using the rectilinear-lens vegetation index (RLVI) as a surrogate for NDVI of a young forest stand. Results showed that LAI was linearly related to NDVI and RLVI, which was largely the result of changes in the deciduous vegetation component across the GS. These results indicate that RLVI could be used as a surrogate for NDVI up to a GS maximum LAI of 0.91 m2 m⁻² observed in 2006. Measured mean (± 1 S.D.) GS LAI was 0.67 (± 0.24) m² m⁻² in 2006. LAI accounted for the majority of the variability in Amax at the 30-day time scale, while at shorter time scales air temperature was the dominant control. For 2004 to 2007, mean spring estimates of LAI were 0.25, 0.29, 0.38 (compared to 0.40 m² m⁻² from measurements) and 0.41 m² m⁻², respectively. Results suggest that a steady increase in the jack pine LAI component accounted for the annual increases in GPP and hence NEP over the four years.

Eddy-covariance (EC) CO₂ flux data were analysed and annual carbon (C) balances estimated for a four-year period (2004-2007) following clearcut harvesting of a boreal jack pine stand in northern Saskatchewan. The site was a source of C to the atmosphere for all years, with annual net ecosystem productivity (NEP) increasing from -153 g C m⁻² yr⁻¹ in 2004 to -63 g C m⁻² yr⁻¹ in 2007. This increase was mainly due to gross primary productivity (GPP) increasing significantly from 78 to 200 g C m⁻² yr⁻¹ , while ecosystem respiration (R) increased only slightly from 231 to 263 g C m⁻² yr⁻¹ over the same period. In the 2006 growing season (GS), a field campaign was conducted to investigate the relationships between monthly destructive measurements of leaf area index (LAI) and daily measurements of the normalized difference vegetation index (NDVI) and photosynthetic capacity (Amax). The latter was derived from 5-day, 16-day, 30-day and annual Michaelis-Menten light response analyses using daytime measurements of NEP and incident photosynthetically active radiation. Digital-camera data were used to evaluate the potential of using the rectilinear-lens vegetation index (RLVI) as a surrogate for NDVI of a young forest stand. Results showed that LAI was linearly related to NDVI and RLVI, which was largely the result of changes in the deciduous vegetation component across the GS. These results indicate that RLVI could be used as a surrogate for NDVI up to a GS maximum LAI of 0.91 m2 m⁻² observed in 2006. Measured mean (± 1 S.D.) GS LAI was 0.67 (± 0.24) m² m⁻² in 2006. LAI accounted for the majority of the variability in Amax at the 30-day time scale, while at shorter time scales air temperature was the dominant control. For 2004 to 2007, mean spring estimates of LAI were 0.25, 0.29, 0.38 (compared to 0.40 m² m⁻² from measurements) and 0.41 m² m⁻², respectively. Results suggest that a steady increase in the jack pine LAI component accounted for the annual increases in GPP and hence NEP over the four years. / Land and Food Systems, Faculty of / Graduate

京都大学 / 0048 / 新制・課程博士 / 博士(農学) / 甲第19781号 / 農博第2177号 / 新制||農||1041(附属図書館) / 学位論文||H28||N4997(農学部図書室) / 32817 / 京都大学大学院農学研究科農学専攻 / (主査)教授 白岩 立彦, 教授 奥本 裕, 教授 稲村 達也 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DFAM

No description available.

Submitted by Renata Lopes (renatasil82@gmail.com) on 2017-05-16T12:20:41Z No. of bitstreams: 1 cristianoferraraderesende.pdf: 1487750 bytes, checksum: df886d8f9947076302c4078f4a93546e (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-05-17T16:14:20Z (GMT) No. of bitstreams: 1 cristianoferraraderesende.pdf: 1487750 bytes, checksum: df886d8f9947076302c4078f4a93546e (MD5) / Made available in DSpace on 2017-05-17T16:14:20Z (GMT). No. of bitstreams: 1 cristianoferraraderesende.pdf: 1487750 bytes, checksum: df886d8f9947076302c4078f4a93546e (MD5) Previous issue date: 2016-08-22 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / FAPEMIG - Fundação de Amparo à Pesquisa do Estado de Minas Gerais / Syzygium jambos (L.) Alston é uma espécie da família Myrtaceae, conhecida popularmente como “jambo-rosa” e originária da Ásia Tropical. Apresenta grande plasticidade fenotípica a condições ambientais contrastantes e uma elevada capacidade invasora, sendo capaz de adaptar-se tanto a áreas abertas quanto de dossel fechado. Seus indivíduos formam uma copa densa, impedindo a colonização de plantas nativas e o estabelecimento de espécies mais dependentes de luz. É, por isso, de grande importância ecológica. Apesar de ser uma espécie invasora de diversas ilhas oceânicas e áreas continentais tropicais, trabalhos que visem entender os mecanismos ecofisiológicos subjacentes a essa capacidade são inexistentes. Dessa forma, objetivou-se descrever as alterações morfológicas, bioquímicas e metabólicas de plantas de S. jambos cultivadas em diferentes condições de luminosidade e fertilização, além de verificar a viabilidade da utilização do clorofilômetro portátil SPAD-502 na determinação indireta dos teores de pigmentos fotossintéticos foliares. Para tal, sementes foram coletadas de um indivíduo estabelecido no Instituto de Ciências Biológicas da UFJF e germinadas, período durante o qual a mobilização de carboidratos cotiledonares foi avaliada. As sementes foram plantadas em copos descartáveis, e após o crescimento até cerca de 11 cm foram transplantadas para vasos de 25 L, preenchidos com substrato formado por terra e areia (controle), substrato adicionado de esterco bovino e um terceiro com adição de adubo químico. As plantas foram transferidas para diferentes ambientes luminosos, denominados de baixa radiação (BR), radiação intermediária (RI) e alta radiação (AR), permanecendo por cerca de 11 meses. Os resultados do presente trabalho demonstraram importantes respostas adaptativas das plantas de S. jambos aos diferentes ambientes luminosos, como, por exemplo, menor desenvolvimento da parte aérea, maior alocação de biomassa nas raízes, menor comprimento de internódios e a presença de folhas em posição mais vertical em plantas a pleno sol. Por sua vez, as plantas sob baixas radiações apresentaram folhas com áreas maiores, além de teores de pigmentos fotossintéticos significativamente maiores, que as plantas sob maiores intensidades luminosas. Houve correlação positiva significativa entre os teores de pigmentos fotossintéticos aferidos espectrofotometricamente e os índices SPAD obtidos com auxílio do clorofilômetro portátil, validando sua utilização na quantificação indireta desses teores em plantas de S. jambos. Com relação ao metabolismo antioxidativo, foram evidenciadas diferentes estratégias de combate à geração de espécies reativas de oxigênio. De forma geral, ressalta-se a maior atividade de enzimas antioxidativas nos ambientes mais sombreados, bem como a maior produção de carotenoides nas folhas desenvolvidas a pleno sol. Os parâmetros fotossintéticos e de fluorescência evidenciaram importantes respostas à variação na luminosidade. Independentemente do ambiente luminoso, as plantas de S. jambos apresentaram crescimento e desenvolvimento, permanecendo viáveis. Os dados do presente trabalho nos permitem concluir que os atributos morfológicos, fisiológicos e bioquímicos apresentados pela espécie invasora Syzygium jambos em condições contrastantes de luminosidade são de grande importância na sua aclimatação e permanência em ambientes naturais diversos, contribuindo para a sua capacidade invasora. / Syzygium jambos (L.) Alston is a species of the Myrtaceae family, popularly known as “rose-apple” and originated in tropical Asia. It has great phenotypic plasticity to contrasting environmental conditions and high invasiveness, being able to adapt to both open areas as closed canopy. Its individuals form a dense crown, preventing colonization of native plants and the establishment of more light dependent species. It is therefore of great ecological importance. Despite being an invasive species in many tropical oceanic islands and continental areas, works aimed at understanding the ecophysiological mechanisms underlying this capacity are scarce. Thus, this study aimed to describe the morphological, biochemical and metabolic alterations in S. jambos plants grown under different light conditions and fertilization systems, and verify the feasibility of using the SPAD-502 chlorophyll meter in indirect determination of the levels of leaf photosynthetic pigments. For that, seeds were collected from one individual established in the Institute of Biological Sciences of UFJF and placed to germinate, during which the mobilization of cotyledon carbohydrates was assessed. The seeds were planted in plastic cups, and after raising to about 11 cm they were transplanted into pots of 25 L, filled with substrate formed by land and sand (control), substrate added with bovine manure and a third with the addition of chemical fertilizer. The plants were transferred to different light environments, called low radiation (BR), intermediate radiation (RI) and high radiation (AR), where they stood for about 10 months. The results of this study showed significant adaptive responses of S. jambos plants to different light environments, such as lower development of the aerial part, higher allocation of biomass in the roots, shorter internodes and the presence of leaves in a more vertical position in plants at full sun. In turn, plants under low radiation showed leaves with larger areas than plants under higher light intensities, in addition to significantly higher levels of photosynthetic pigments. There was a significant positive correlation between the levels of photosynthetic pigments measured spectrophotometrically and the SPAD indices, obtained with the help of chlorophyll meter, validating its use in indirect quantification of these levels in S. jambos plants. Regarding the antioxidative metabolism, there were different strategies to combat the formation of reactive oxygen species. Overall, the study highlights the increased activity of antioxidant enzymes in shadier environments, as well as increased production of carotenoids in the leaves developed in full sun. The photosynthetic and fluorescence parameters showed significant responses to changes in light condition. Regardless of the ambient light, plants of S. jambos showed growth and development while remaining viable. The present data allow us to conclude that the morphological, physiological and biochemical attributes presented by the invasive species Syzygium jambos in contrasting light conditions are of great importance for their acclimation and permanence in different natural environments, contributing to its invasiveness.