Isoprene Emission and Carbon Dioxide Protect Aspen Leaves from Heat Stress

High temperature, especially above 35oC, is known to reduce leaf photosynthetic rate in many tree species. This study investigated the effect of high temperature on isoprene-emitting (aspen) and non- emitting (birch) trees under ambient and elevated CO2 under open field conditions. Aspen trees tolerate heat better than birch trees and elevated CO2 protects both species against moderate heat stress. The increased thermotolerance in aspen trees compared to the birch trees may result from the aspen's ability to produce isoprene. Elevated CO2 increased carboxylation capacity, photosynthetic electron transport capacity and triose phosphate use in both birch and aspen trees. High temperature decreased all of these parameters in birch regardless of CO2 treatment but only photosynthetic electron transport and triose phosphate use at ambient CO2 were reduced in aspen. As temperature rises, non-isoprene-emitting trees will be at a disadvantage and biological diversity and species richness might be lost in some ecosystems. Our results indicate that isoprene emitting tree species will have an advantage over non-isoprene emitting ones under high temperatures

Plants having modified reproductive capacity

This invention relates to plants having modified reproductive capacity. In particular, it relates to a plant reproductive tissue specific promoter, the PrAGl promoter isolated from Pinus radiata, and its use in promoting transcription/ expression of associated sequences in plant reproductive tissue, including for the purpose of producing plants which have diminished reproductive capacity or which are sterile.https://digitalcommons.mtu.edu/patents/1048/thumbnail.jp

Application of aspen MADS-box genes to alter reproduction and development in trees

The present invention provides compositions and methods for producing a transgenic plant that exhibits altered characteristics resulting from over expression or under expression of a novel polypeptide PtM3 or its homolog PtM4. The altered characteristics resulting from over-expression include at least one of the ability to convert axillary mer- istem to floral meristem; to accelerate flowering i.e., early flowering; to increase fruit production; to increase nut production; to increase seed output; to increase branching; to increase flower production; to increase fruit yield; to increase flower yield and a combination thereof. The altered characteristics resulting from suppressed expression include at least one of complete sterility; partial sterility (sterility of only one sex of a bisexual plant); reduced pollen production; decreased flowering; increased biomass and combinations thereof. Furthermore, once the transgenic plant is sterile, additional exogenous sequences may be incorporated into the sterile plant genome, resulting in other desired plant characteristics. Related promoter, gene constructs, methods, antibodies and kits are also provided.https://digitalcommons.mtu.edu/patents/1041/thumbnail.jp

An Integrated Functional Genomics Consortium to Increase Carbon Sequestration in Poplars: Optimizing Aboveground Carbon Gain

This project used gene expression patterns from two forest Free-Air CO2 Enrichment (FACE) experiments (Aspen FACE in northern Wisconsin and POPFACE in Italy) to examine ways to increase the aboveground carbon sequestration potential of poplars (Populus). The aim was to use patterns of global gene expression to identify candidate genes for increased carbon sequestration. Gene expression studies were linked to physiological measurements in order to elucidate bottlenecks in carbon acquisition in trees grown in elevated CO2 conditions. Delayed senescence allowing additional carbon uptake late in the growing season, was also examined, and expression of target genes was tested in elite P. deltoides x P. trichocarpa hybrids. In Populus euramericana, gene expression was sensitive to elevated CO2, but the response depended on the developmental age of the leaves. Most differentially expressed genes were upregulated in elevated CO2 in young leaves, while most were downregulated in elevated CO2 in semi-mature leaves. In P. deltoides x P. trichocarpa hybrids, leaf development and leaf quality traits, including leaf area, leaf shape, epidermal cell area, stomatal number, specific leaf area, and canopy senescence were sensitive to elevated CO2. Significant increases under elevated CO2 occurred for both above- and belowground growth in the F-2 generation. Three areas of the genome played a role in determining aboveground growth response to elevated CO2, with three additional areas of the genome important in determining belowground growth responses to elevated CO2. In Populus tremuloides, CO2-responsive genes in leaves were found to differ between two aspen clones that showed different growth responses, despite similarity in many physiological parameters (photosynthesis, stomatal conductance, and leaf area index). The CO2-responsive clone shunted C into pathways associated with active defense/response to stress, carbohydrate/starch biosynthesis and subsequent growth. The CO2-unresponsive clone partitioned C into pathways associated with passive defense and cell wall thickening. These results indicate that there is significant variation in gene expression patterns between different tree genotypes. Consequently, future efforts to improve productivity or other advantageous traits for carbon sequestration should include an examination of genetic variability in CO2 responsiveness

Summer 1982

Registration of Isofenphos (page 3) Managing Annual Bluegrass (4) Helminthosporium Leaf Spot Fungicide Control Trial--1981 (8) Cultivar Trials--1981 (9) Dollar Spot (Sclerotinia Homeocarpa Sp.) Fungicide Control Trial--1981 (14) Living with the Gypsy Moth (15

Elevated carbon dioxide and ozone alter productivity and ecosystem carbon content in northern temperate forests

Three young northern temperate forest communities in the north‐central United States were exposed to factorial combinations of elevated carbon dioxide ( CO 2 ) and tropospheric ozone (O 3 ) for 11 years. Here, we report results from an extensive sampling of plant biomass and soil conducted at the conclusion of the experiment that enabled us to estimate ecosystem carbon (C) content and cumulative net primary productivity ( NPP ). Elevated CO 2 enhanced ecosystem C content by 11%, whereas elevated O 3 decreased ecosystem C content by 9%. There was little variation in treatment effects on C content across communities and no meaningful interactions between CO 2 and O 3 . Treatment effects on ecosystem C content resulted primarily from changes in the near‐surface mineral soil and tree C, particularly differences in woody tissues. Excluding the mineral soil, cumulative NPP was a strong predictor of ecosystem C content ( r 2  = 0.96). Elevated CO 2 enhanced cumulative NPP by 39%, a consequence of a 28% increase in canopy nitrogen (N) content (g N m −2 ) and a 28% increase in N productivity ( NPP /canopy N). In contrast, elevated O 3 lowered NPP by 10% because of a 21% decrease in canopy N, but did not impact N productivity. Consequently, as the marginal impact of canopy N on NPP (∆ NPP /∆N) decreased through time with further canopy development, the O 3 effect on NPP dissipated. Within the mineral soil, there was less C in the top 0.1 m of soil under elevated O 3 and less soil C from 0.1 to 0.2 m in depth under elevated CO 2 . Overall, these results suggest that elevated CO 2 may create a sustained increase in NPP , whereas the long‐term effect of elevated O 3 on NPP will be smaller than expected. However, changes in soil C are not well‐understood and limit our ability to predict changes in ecosystem C content.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/108065/1/gcb12564.pd

Elevated carbon dioxide and ozone alter productivity and ecosystem carbon content in northern temperate forests

Three young northern temperate forest communities in the north-central United States were exposed to factorial combinations of elevated carbon dioxide (CO2) and tropospheric ozone (O3) for 11 years. Here, we report results from an extensive sampling of plant biomass and soil conducted at the conclusion of the experiment that enabled us to estimate ecosystem carbon (C) content and cumulative net primary productivity (NPP). Elevated CO2 enhanced ecosystem C content by 11%, whereas elevated O3 decreased ecosystem C content by 9%. There was little variation in treatment effects on C content across communities and no meaningful interactions between CO2 and O3. Treatment effects on ecosystem C content resulted primarily from changes in the near-surface mineral soil and tree C, particularly differences in woody tissues. Excluding the mineral soil, cumulative NPP was a strong predictor of ecosystem C content (r2 = 0.96). Elevated CO2 enhanced cumulative NPP by 39%, a consequence of a 28% increase in canopy nitrogen (N) content (g N m−2) and a 28% increase in N productivity (NPP/canopy N). In contrast, elevated O3 lowered NPP by 10% because of a 21% decrease in canopy N, but did not impact N productivity. Consequently, as the marginal impact of canopy N on NPP (ΔNPP/ΔN) decreased through time with further canopy development, the O3 effect on NPP dissipated. Within the mineral soil, there was less C in the top 0.1 m of soil under elevated O3 and less soil C from 0.1 to 0.2 m in depth under elevated CO2. Overall, these results suggest that elevated CO2 may create a sustained increase in NPP, whereas the long-term effect of elevated O3 on NPP will be smaller than expected. However, changes in soil C are not well-understood and limit our ability to predict changes in ecosystem C content

Importance of carbon-nitrogen interactions and ozone on ecosystem hydrology during the 21st century

Author Posting. © American Geophysical Union, 2009. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 114 (2009): G01020, doi:10.1029/2008JG000826.There is evidence that increasing CO2 concentrations have reduced evapotranspiration and increased runoff through reductions in stomatal conductance during the twentieth century. While this process will continue to counteract increased evapotranspiration associated with future warming, it is highly dependent upon concurrent changes in photosynthesis, especially due to CO2 fertilization, nitrogen limitation, and ozone exposure. A new version of the Terrestrial Ecosystem Model (TEM-Hydro) was developed to examine the effects of carbon and nitrogen on the water cycle. We used two climate models (NCAR CCSM3 and DOE PCM) and two emissions scenarios (SRES B1 and A2) to examine the effects of climate, elevated CO2, nitrogen limitation, and ozone exposure on the hydrological cycle in the eastern United States. While the direction of future runoff changes is largely dependent upon predicted precipitation changes, the effects of elevated CO2 on ecosystem function (stomatal closure and CO2 fertilization) increase runoff by 3–7%, as compared to the effects of climate alone. Consideration of nitrogen limitation and ozone damage on photosynthesis increases runoff by a further 6–11%. Failure to consider the effects of the interactions among nitrogen, ozone, and elevated CO2 may lead to significant regional underestimates of future runoff.This study was funded by the Interdisciplinary Science Program of the U.S. National Aeronautics and Space Administration (NNG04GJ80G, NNG04GM39G), the Dynamic Global Economic Modeling of Greenhouse Gas Emissions and Mitigation from Land-Use Activities of the U.S. Environmental Protection Agency (XA-83240101), and the Nonlinear Response to Global Change in Linked Aquatic and Terrestrial Ecosystems of the U.S. EPA (XA-83326101)

Impacts of elevated atmospheric CO2 on forest trees and forest ecosystems: knowledge gaps

and forest ecosystems: knowledge gap