Thesis Chapters by Estefanía Milla-Moreno
In leaves, the ease with which CO2 may diffuse from substomatal cavities to the sites of carboxyl... more In leaves, the ease with which CO2 may diffuse from substomatal cavities to the sites of carboxylation (mesophyll conductance, gm) is inversely proportional to the pathway length in the gas phase and the structural resistances encountered in the liquid phase. Increased length of any pathway component should decrease gm, whereas increased area for diffusion should increase gm. There is evidence that within native balsam poplar (Populus balsamifera L.) populations, gm may increase with latitude of origin, as do leaf mass (LMA) and nitrogen per unit area. To investigate the internal structural characteristics that might limit maximum gm in leaves, a balsam poplar family (K4×C) known to have high variation in LMA was chosen. Several whole tissue properties (LMA, carbon-nitrogen ratio, chlorophyll concentration index), microanatomy traits (leaf thickness, intercellular air space, cell wall surface area, chloroplast counts), and ultrastructural attributes (cell wall thickness, thylakoid grana thickness, and cell wall area adjacent to chloroplasts) were measured.
There were significant genotypic differences in chlorophyll concentration index, numbers of chloroplasts per mesophyll cell, leaf thickness (tleaf), and thicknesses and cross-sectional areas of the palisade and spongy mesophyll layers. There were also differences in the fraction of intercellular air space (fias), as well as total and exposed cell wall surface areas of the mesophyll and its component tissues. Although genotypic differences in LMA were not significant, LMA varied as a function of tleaf (r=0.515, p<0.05) and fias (r=-0.510, p<0.05), which together explained considerable variation in this trait. The single best correlate of LMA was the cell wall area of the palisade (r=0.813, p<0.001), which accounted for well over half of the total cell wall area of the mesophyll. The areas of mesophyll cell walls and chloroplasts exposed to intercellular air space, both of which should contribute to gm, also increased with LMA. Along the same lines, but not correlated with LMA, there was a decrease in nitrogen density per unit exposed mesophyll surface area associated with thicker leaves (r=-0.481, p<0.05).
Water is the main limiting factor for the development of agricultural species and forest species.... more Water is the main limiting factor for the development of agricultural species and forest species. In Chile more than ¾ of the land surface corresponds to arid and semiarid areas. Several studies have shown that species of the genus Eucalyptus, have a wide potential in the tolerance to limited rainfall. For this reason, we evaluate the effect of water availability in some responses of three species of Eucalyptus: Eucalyptus globulus, Eucalyptus camaldulensis and Eucalyptus cladocalyx.
The plants were subjected to three levels of water availability, defined as: no stress, moderate stress and severe stress. The plants were kept under semi-controlled environments and responses were evaluated during two cycles of drying at the end of each cycle, plants were rehydrated for one week. The results indicate that E. camaldulensis had higher physiological plasticity with respect to the values of stem water potential, stomatal conductance, photosynthesis (with E. cladocalyx) and chlorophyll fluorescence.
The availability of water treatments are applied in a first phase, lasting five weeks, then recover with watering plants for a week, then re-apply for water restriction treatments for nine weeks. Finally, we apply a week of recovery with irrigation.
The study includes 90 eucalyptus plants, 30 species, which are arranged in a factorial design of five blocks at random.
The major constraint observed in Eucalyptus camaldulensis and Eucalyptus cladocalyx with water restriction, is of type stomatal directly influence photosynthesis, internal CO2 concentration and stomatal conductance. In E. globulus, meanwhile, is metabolic.
This experiment allowed us to confirm that E. camaldulensis and E. cladocalyx tolerate water deficit, being entitled to be located in areas with low water availability, such as semi-arid and arid areas of Chile.
Keywords
E. camaldulensis, E. cladocalyx, E. globulus, water stress.
Conference Presentations by Estefanía Milla-Moreno
Papers by Estefanía Milla-Moreno
Modifications to leaf structural components that drive variation in leaf mass per area (LMA) may ... more Modifications to leaf structural components that drive variation in leaf mass per area (LMA) may substantially impact leaf physiology by changing how easily CO2 diffuses through intercellular air space to carboxylation sites in mesophyll tissues. Mesophyll conductance (gm) is inversely proportional to the total pathway length for CO2, including the structural resistances encountered. In balsam poplar (Populus balsamifera), gm increases with latitude, paralleled by an increase in LMA. We investigated a P. balsamifera family (K4×C) with high variation in LMA for different characteristics (tissues, nitrogen content, ultrastructural attributes). We interpreted trait variability using a developmental scale quantified by the Leaf Plastochron Index (LPI). Developmental age significantly affected LMA, but those effects were lost at LPI≥6. We outlined contributions of anatomical components to LMA and found palisade mesophyll properties were the primary drivers of variation in LMA within matu...
International Journal of Phytoremediation
Water is the main limiting factor for the development of agricultural species and forest species.... more Water is the main limiting factor for the development of agricultural species and forest species. In Chile more than ¾ of the land surface corresponds to arid and semiarid areas. Several studies have shown that species of the genus Eucalyptus, have a wide potential in the tolerance to limited rainfall. For this reason, we evaluate the effect of water availability in some responses of three species of Eucalyptus: Eucalyptus globulus, Eucalyptus camaldulensis and Eucalyptus cladocalyx. The plants were subjected to three levels of water availability, defined as: no stress, moderate stress and severe stress. The plants were kept under semi-controlled environments and responses were evaluated during two cycles of drying at the end of each cycle, plants were rehydrated for one week. The results indicate that E. camaldulensis had higher physiological plasticity with respect to the values of stem water potential, stomatal conductance, photosynthesis (with E. cladocalyx) and chlorophyll fluo...
Water is the main limiting factor for the development of agricultural species and forest species.... more Water is the main limiting factor for the development of agricultural species and forest species. In Chile more than ¾ of the land surface corresponds to arid and semiarid areas. Several studies have shown that species of the genus Eucalyptus, have a wide potential in the tolerance to limited rainfall. For this reason, we evaluate the effect of water availability in some responses of three species of Eucalyptus: Eucalyptus globulus, Eucalyptus camaldulensis and Eucalyptus cladocalyx. The plants were subjected to three levels of water availability, defined as: no stress, moderate stress and severe stress. The plants were kept under semi-controlled environments and responses were evaluated during two cycles of drying at the end of each cycle, plants were rehydrated for one week. The results indicate that E. camaldulensis had higher physiological plasticity with respect to the values of stem water potential, stomatal conductance, photosynthesis (with E. cladocalyx) and chlorophyll fluo...
Toxics
In the present climate emergency due to global warming, we are urged to move away from fossil fue... more In the present climate emergency due to global warming, we are urged to move away from fossil fuels and pursue a speedy conversion to renewable energy systems. Consequently, copper (Cu) will remain in high demand because it is a highly efficient conductor used in clean energy systems to generate power from solar, hydro, thermal and wind energy across the world. Chile is the global leader in copper production, but this position has resulted in Chile having several hundred tailing deposits. We grew two Chilean native hardwood species, quillay (Quillaja saponaria Molina) and espino (Vachellia caven (Molina) Seigler & Ebinger, under three increasing Cu levels (0, 50, and 100 µM) for 6 months in a greenhouse setting. We measured growth, photosynthetic performance and elemental contents of leaves and roots to further evaluate their potential for phytoremediation. Growth of quillay was unaffected by Cu treatment but growth of espino was enhanced, as was its photosynthetic performance, indi...
Botany, 2016
Modifications to leaf structural components that drive variation in leaf mass per area (LMA) may ... more Modifications to leaf structural components that drive variation in leaf mass per area (LMA) may substantially impact leaf physiology by changing how easily CO2 diffuses through intercellular air space to carboxylation sites in mesophyll tissues. Mesophyll conductance (gm) is inversely proportional to the total pathway length for CO2, including the structural resistances encountered. In balsam poplar (Populus balsamifera L.), gm increases with latitude, paralleled by an increase in LMA. We investigated a family of P. balsamifera (K4×C) with high variation in LMA for different characteristics (tissues, nitrogen content, ultrastructural attributes). We interpreted trait variability using a developmental scale quantified by the leaf plastochron index (LPI). Developmental age significantly affected LMA, but those effects were lost at LPI ≥ 6. We outlined contributions of anatomical components to LMA and found palisade mesophyll properties were the primary drivers of variation in LMA wit...
In leaves, the ease with which CO2 may diffuse from substomatal cavities to the sites of carboxyl... more In leaves, the ease with which CO2 may diffuse from substomatal cavities to the sites of carboxylation (mesophyll conductance, gm) is inversely proportional to the pathway length in the gas phase and the structural resistances encountered in the liquid phase. Increased length of any pathway component should decrease gm, whereas increased area for diffusion should increase gm. There is evidence that within native balsam poplar (Populus balsamifera L.) populations, gm may increase with latitude of origin, as do leaf mass (LMA) and nitrogen per unit area. To investigate the internal structural characteristics that might limit maximum gm in leaves, a balsam poplar family (K4×C) known to have high variation in LMA was chosen. Several whole tissue properties (LMA, carbon-nitrogen ratio, chlorophyll concentration index), microanatomy traits (leaf thickness, intercellular air space, cell wall surface area, chloroplast counts), and ultrastructural attributes (cell wall thickness, thylakoid g...
International Journal of Phytoremediation, 2020
Chile has many mine tailing deposits available for phytoremediation through the establishment of ... more Chile has many mine tailing deposits available for phytoremediation through the establishment of metal-tolerant plants. To guide such efforts, it is necessary to know whether roots exclude or take up metals, or if metals are mobilized to shoots. We evaluated a polyculture of ten native species 6 years after they were planted directly into tailings, amended with mycorrhiza before planting or planted with compost. All species were assessed for survival and hare damage. Growth, vigor, chlorophyll content index, and chlorophyll fluorescence were measured in seven species, and root and shoot concentrations of 11 metals and As were measured in five. All species had some level of stress, but there was no clear pattern related to foliar metal concentrations or amendments, the latter also having little effect on growth or survival. Copper, Fe, and Mo concentrations exceeded threshold toxicity levels for leaves and for animal feed in several species. Copper was most concentrated in the roots, and readily mobilized to leaves in three of the five species tested, but not in Prosopis chilensis (algarrobo) and Quillaja saponaria (quillay). Because of lower uptake overall, quillay is recommended for stabilizing tailings while also reducing transport to aerial tissues.
Modifications to leaf structural components that drive variation in leaf mass per area (LMA) may ... more Modifications to leaf structural components that drive variation in leaf mass per area (LMA) may substantially impact leaf physiology by changing how easily CO 2 diffuses through intercellular air space to carboxylation sites in mesophyll tissues. Mesophyll conductance (g m) is inversely proportional to the total pathway length for CO 2 , including the structural resistances encountered. In balsam poplar (Populus balsamifera L.), g m increases with latitude, paralleled by an increase in LMA. We investigated a family of P. balsamifera (K4×C) with high variation in LMA for different characteristics (tissues, nitrogen content, ultrastructural attributes). We interpreted trait variability using a developmental scale quantified by the leaf plastochron index (LPI). Developmental age significantly affected LMA, but those effects were lost at LPI ≥ 6. We outlined contributions of anatomical components to LMA and found palisade mesophyll properties were the primary drivers of variation in LMA within mature leaves (LPI ≥ 6). Using anatomical data, we derived components corresponding to structural resistances for g m. Perimeters of palisade cells and surface area of palisade exposed to intercellular air space, which may strongly influence CO 2 diffusion, were correlated to LMA. Variation in LMA is positively related to differences in structural features expected to increase the conductance to CO 2 diffusion within palisade mesophyll. Résumé : Les modifications apportées aux composantes structurales de la feuille qui sous-tendent la variation de la masse surfacique foliaire (MSF) peuvent avoir un impact important sur la physiologie foliaire en changeant la facilité avec laquelle le CO 2 diffuse a ` travers l'espace aérien intercellulaire aux sites de carboxylation dans le mésophylle. La conductance du mésophylle (g m) est inversement proportionnelle a ` la longueur totale du sentier parcouru par le CO 2 , incluant les résistances structurales rencontrées. Chez le peuplier baumier (Populus balsamifera L.), la g m augmente en fonction de la latitude parallèlement a ` l'augmentation de la MSF. Les auteurs ont examiné une famille de P. balsamifera (K4×C) dont la MSF est hautement variable, sur le plan de différentes caractéristiques (tissus, contenu en azote, attributs ultrastructuraux). Ils ont interprété la variabilité a ` l'aide d'une échelle dével-oppementale quantifiée par l'indice plastochrone foliaire (IPF). L'âge développemental affectait significativement la MSF, mais ces effets disparaissaient a ` un IPF ≥ 6. Ils ont défini les contributions des composantes anatomiques a ` la MSF et trouvé que les propriétés du mésophylle palissadique sont les principaux moteurs de la variation de la MSF a ` l'intérieur des feuilles matures (IPF ≥ 6). Ils ont déduit a ` l'aide des données anatomiques les composantes correspondant aux résistances structurales du g m. Les périmètres des cellules palissadiques et la surface palissadique exposée a ` l'espace aérien intercellulaire, qui pourraient influencer fortement la diffusion de CO 2 , étaient corrélés avec la MSF. La variation de MSF est reliée positivement aux différences des caractéristiques structurales censées accroitre la conductance a ` la diffusion de CO 2 a ` l'intérieur du mésophylle palissadique. [Traduit par la Rédaction] Mots-clés : conductance du mésophylle, g m , peuplier baumier, MSF, micro-anatomie, ultrastructure, physiologie foliaire.
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Thesis Chapters by Estefanía Milla-Moreno
There were significant genotypic differences in chlorophyll concentration index, numbers of chloroplasts per mesophyll cell, leaf thickness (tleaf), and thicknesses and cross-sectional areas of the palisade and spongy mesophyll layers. There were also differences in the fraction of intercellular air space (fias), as well as total and exposed cell wall surface areas of the mesophyll and its component tissues. Although genotypic differences in LMA were not significant, LMA varied as a function of tleaf (r=0.515, p<0.05) and fias (r=-0.510, p<0.05), which together explained considerable variation in this trait. The single best correlate of LMA was the cell wall area of the palisade (r=0.813, p<0.001), which accounted for well over half of the total cell wall area of the mesophyll. The areas of mesophyll cell walls and chloroplasts exposed to intercellular air space, both of which should contribute to gm, also increased with LMA. Along the same lines, but not correlated with LMA, there was a decrease in nitrogen density per unit exposed mesophyll surface area associated with thicker leaves (r=-0.481, p<0.05).
The plants were subjected to three levels of water availability, defined as: no stress, moderate stress and severe stress. The plants were kept under semi-controlled environments and responses were evaluated during two cycles of drying at the end of each cycle, plants were rehydrated for one week. The results indicate that E. camaldulensis had higher physiological plasticity with respect to the values of stem water potential, stomatal conductance, photosynthesis (with E. cladocalyx) and chlorophyll fluorescence.
The availability of water treatments are applied in a first phase, lasting five weeks, then recover with watering plants for a week, then re-apply for water restriction treatments for nine weeks. Finally, we apply a week of recovery with irrigation.
The study includes 90 eucalyptus plants, 30 species, which are arranged in a factorial design of five blocks at random.
The major constraint observed in Eucalyptus camaldulensis and Eucalyptus cladocalyx with water restriction, is of type stomatal directly influence photosynthesis, internal CO2 concentration and stomatal conductance. In E. globulus, meanwhile, is metabolic.
This experiment allowed us to confirm that E. camaldulensis and E. cladocalyx tolerate water deficit, being entitled to be located in areas with low water availability, such as semi-arid and arid areas of Chile.
Keywords
E. camaldulensis, E. cladocalyx, E. globulus, water stress.
Conference Presentations by Estefanía Milla-Moreno
Papers by Estefanía Milla-Moreno
There were significant genotypic differences in chlorophyll concentration index, numbers of chloroplasts per mesophyll cell, leaf thickness (tleaf), and thicknesses and cross-sectional areas of the palisade and spongy mesophyll layers. There were also differences in the fraction of intercellular air space (fias), as well as total and exposed cell wall surface areas of the mesophyll and its component tissues. Although genotypic differences in LMA were not significant, LMA varied as a function of tleaf (r=0.515, p<0.05) and fias (r=-0.510, p<0.05), which together explained considerable variation in this trait. The single best correlate of LMA was the cell wall area of the palisade (r=0.813, p<0.001), which accounted for well over half of the total cell wall area of the mesophyll. The areas of mesophyll cell walls and chloroplasts exposed to intercellular air space, both of which should contribute to gm, also increased with LMA. Along the same lines, but not correlated with LMA, there was a decrease in nitrogen density per unit exposed mesophyll surface area associated with thicker leaves (r=-0.481, p<0.05).
The plants were subjected to three levels of water availability, defined as: no stress, moderate stress and severe stress. The plants were kept under semi-controlled environments and responses were evaluated during two cycles of drying at the end of each cycle, plants were rehydrated for one week. The results indicate that E. camaldulensis had higher physiological plasticity with respect to the values of stem water potential, stomatal conductance, photosynthesis (with E. cladocalyx) and chlorophyll fluorescence.
The availability of water treatments are applied in a first phase, lasting five weeks, then recover with watering plants for a week, then re-apply for water restriction treatments for nine weeks. Finally, we apply a week of recovery with irrigation.
The study includes 90 eucalyptus plants, 30 species, which are arranged in a factorial design of five blocks at random.
The major constraint observed in Eucalyptus camaldulensis and Eucalyptus cladocalyx with water restriction, is of type stomatal directly influence photosynthesis, internal CO2 concentration and stomatal conductance. In E. globulus, meanwhile, is metabolic.
This experiment allowed us to confirm that E. camaldulensis and E. cladocalyx tolerate water deficit, being entitled to be located in areas with low water availability, such as semi-arid and arid areas of Chile.
Keywords
E. camaldulensis, E. cladocalyx, E. globulus, water stress.