Download or read book Carbon Dioxide and Water Exchange Rates by a Wheat Crop in NASA s Biomass Production Chamber Results from an 86 day Study January to April 1989 written by R. M. Wheeler and published by . This book was released on 1990 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Carbon Dioxide and Water Exchange Rates by a Wheat Crop in Nasa s Biomass Production Chamber Results from an 86 Day Study January to April 1989 written by National Aeronautics and Space Adm Nasa and published by Independently Published. This book was released on 2018-10-23 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: Gas exchange measurements were taken for a 20 sq m wheat stand grown from seed to harvest in NASA's Biomass Production Chamber. Respiration of the wheat stand caused the CO2 concentrations to rise an average of 440 ppm during the 4-h dark period each day, or 7.2 umol/sq m/sec. Dark period respiration was sensitive to temperature changes and could be increased 70 to 75 percent by raising the temperature from 16 C to 24 C. Stand photosynthesis (measured from the rate of CO2 drawdown immediately after the lights came on each day) peaked at 27 umol/sq m/sec at 25 days after planting and averaged 15 umol/sq m/sec throughout the study. By combining the average light period photosynthesis and average dark period respiration, a net of 860 g or 470 liters of CO2 were fixed per day. Stand photosynthetic rates showed a linear increase with increasing irradiance (750 umol/sq m/sec PPF the highest level tested), with an average light compensation point after day 30 of 190 umol/sq m/sec. Stand photosynthesis decreased slightly when CO2 levels were decreased from 2200 to 800 ppm, but dropped sharply when CO2 was decreased below 700 to 800 ppm. Water production from stand transpiration peaked at 120 L/day near 25 days and averaged about 90 L/day, or 4.5 L/sq m/day throughout the study. Wheeler, R. M. and Sager, J. C. Kennedy Space Center
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1990 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Publications of the NASA Controlled Ecological Life Support Systems CELSS Program 1989 1992 written by Janet V. Powers and published by . This book was released on 1994 with total page 58 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Aerospace Medicine and Biology written by and published by . This book was released on 1991 with total page 486 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Technology 2000 written by and published by . This book was released on 1991 with total page 388 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Crop Production for Advanced Life Support Systems Observations From the Kennedy Space Center Breadboard Project written by and published by . This book was released on 2003 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Government Reports Annual Index written by and published by . This book was released on 1991 with total page 1646 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sections 1-2. Keyword Index.--Section 3. Personal author index.--Section 4. Corporate author index.-- Section 5. Contract/grant number index, NTIS order/report number index 1-E.--Section 6. NTIS order/report number index F-Z.
Download or read book Government Reports Announcements Index written by and published by . This book was released on 1991 with total page 628 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book NASA Conference Publication written by and published by . This book was released on 1991 with total page 824 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Technology 2000 Volume 2 written by and published by . This book was released on 1991 with total page 390 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Investigating Combustion as a Method of Processing Inedible Biomass Produced in NASA s Biomass Production Chamber written by and published by . This book was released on 1991 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Life Sciences and Space Research XXV 3 written by COSPAR. Plenary Meeting and published by Elsevier Science & Technology. This book was released on 1994 with total page 488 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Atmospheric Leakage and Condensate Production in NASA s Biomass Production Chamber Effect of Diurnal Temperature Cycles written by and published by . This book was released on 1991 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Potential Effects of Global Climate Change on the United States written by and published by . This book was released on 1989 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Long term Effects of Climate and Nitrogen on Wheat Triticum Aestivum Carbon water Relations in California written by Laura Elizabeth Emberson and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The tracking of crop yields as affected by climate variability and rising carbon dioxide (CO2) levels is essential in creating a framework for sustainable agricultural management decisions in the future (Izaurralde et al. 2003; Rosenberg et al. 2003; Asseng et al. 2015). In this research, winter wheat grown in an arid climate is used as a model system to understand climate and atmospheric changes on crop yield potential. (Idso et al. 1979; Smit et al. 1988; Daniel et al. 2002; Asseng et al. 2015; Stratonovitch and Semenov 2015). Wheat is the third most commonly produced crop in the world (kg/ha) (Field to Market 2012). The following study investigates 16 years of field data (1998-2013) collected from the Century Experiment at Russell Ranch Sustainable Agricultural Facility at Davis, California. The climate at Russell Ranch covers a range of conditions from severe drought to unusually moist, representing total rainfall from 221.1 mm to 735 mm. However, results indicate that the water stress metrics used to describe seasonal water status do not have significant effects on yield outcomes. Analyses also indicate that there is no effect of carbon dioxide on yield within the range from 360-400 ppm during the study period. Results show a strong correlation between nitrogen availability and yields, when controlling for yearly variability and variability within plots of replicated treatments. Results also show that the physiological indicator of stress, represented by carbon-13 discrimination in the grain, improves the modelled description of yield. Other findings indicate that nitrogen limitations have caused much greater stress on yields than climate variability since 1998. The anisohydric adaptation of wheat is hypothesized to be a mechanism to cope with water stress. This plant strategy maintains photosynthetic capacity under stress, by favoring stomatal conductance over turgor pressure. An abiotic explanation of these results suggests climatic conditions have not reached threshold conditions to cause yield changes. Carbon dioxide levels, for instance are currently near 400 ppm, while carbon enrichment experiments only show growth effects above 550 ppm in elevated CO2 experiments. Likely, both explanations are partly responsible for the result. These findings suggest that wheat culture will remain resilient to future climate change and atmospheric change. Chapter 2: Consideration of [delta]13C and [delta]18O in wheat to understand physiological stress and weather reconstruction in a Mediterranean climate Stable isotope signatures of carbon and oxygen in wheat reflect an integrated measure of stomatal aperture throughout the season due to the interface between carbon dioxide being assimilated and water being transpired at the stomatal pore. Stomata close when available water is scare and evapotranspiration rates are high (Barbour et al. 2000; Ainsworth and Long 2005; Farooq et al. 2014). This connection between stomatal conductance and water status is reflected in the strong negative trend of [delta]13C and the strong positive trend of 18O in wheat with increasing vapor pressure deficit (Roden et al. 2000; Fry 2006).This investigation examines the relationship between 13C discrimination ([delta]13C), 18O enrichment ([delta]18O), and weather factors in three plant materials. Wheat bulk straw, straw cellulose, and bulk grain samples archived during a long-term agricultural field experiment. The field experiments original design also has three soil nitrogen treatments (Torbert et al. 2016). This archival data provided two decades worth of samples grown under natural weather conditions, rather than imposed water and carbon dioxide levels. The four major climate factors of interest were seasonal precipitation, the Palmer Drought Severity Index (PDSI), potential evapotranspiration (ETo), and atmospheric carbon dioxide concentration.Changes in stable isotope signatures indicate wheat is experiencing a physiological stress and is responding by stomatal closure. Carbon-13 discrimination had a negative correlation to evapotranspiration as expected, but had no relation to any other weather metric. Oxygen-18 enrichment values had a strong positive correlation with evapotranspiration in all sample types. Grain [delta]18O and cellulose [delta]13C had the most sensitive signals to changes in ETo. Straw cellulose [delta]18O was also strongly correlated to drought severity. The significant negative correlation between carbon and oxygen verifies that the changes in carbon signatures are due to water stress and not other factors. The disparity between [delta]18O responding to both ETo and PDSI, while [delta]13C only responded to ETo illuminates two points. It is evidence that oxygen isotopes are better proxies, in general, for climate conditions than carbon isotopes and that carbon isotope data, paired with [delta]18O data is better for accurately identifying stomatal response to external climate conditions. All the findings above indicate that wheat is under physiological stress throughout the field conditions experienced (Farquhar et al. 1989; Condon et al. 1992; Cabrera-Bosquet et al. 2009a). However, the results also reveal that precipitation conditions over the past two decades of experimentation was not driving the stomatal closure response. Rather, wheat stomata are responsive to the vapor pressure deficit increases and rising temperatures captured in higher ETo values. This study highlights the fact that although the utilization of isotope signatures as proxies has blossomed over the past 40 years, it is essential to understand the isotopes in context of the study to avoid incorrect water stress conclusions.
Download or read book Growing Wheat to Maturity in Reduced Gas Pressures written by National Aeronautics and Space Adm Nasa and published by Independently Published. This book was released on 2018-11-02 with total page 70 pages. Available in PDF, EPUB and Kindle. Book excerpt: The main objective of this project was to determine assimilation of CO2 and efficiency of water use in wheat grown to maturity in a low pressure total gas pressure environment. A functional test of the low pressure plant growth chamber system was accomplished in February and March of 1993 wherein this objective was partially achieved. Plants were grown to maturity in the chambers. Data were actively collected during the first 29 days. The plants were allowed to maintain themselves at the CO2 compensation point until day 45 of the study at which point active atmospheric regulation was resumed. This provided data at the vegetative and reproductive stages of the life cycle of the plants. However, this information may not be representative of the performance of the plants due to the loss of low pressure on a number of days during the study, which affected the plants by changing the pressure potential of the tissues. The performance of the system will be discussed on a component by component basis. The maintenance of the plants at the CO2 compensation point was driven by the failure of the computer program operating the system. The software problems that arose during the functional test have since been corrected. Results from the functional test also indicated that the plants were not receiving adequate light and nutrients. The growth chambers have been relocated and the growth room modified to compensate for these deficiencies. Rykiel, Edward J., Jr. and Drew, Malcolm C. and Etter, Brad D. Unspecified Center...
