scholarly journals Hypobaria Affects Gas Exchange, Ethylene Evolution and Growth of Lettuce in NASA Advanced Life Support Systems (ALS)

HortScience ◽  
2004 ◽  
Vol 39 (4) ◽  
pp. 794A-794
Author(s):  
Chuanjiu He ◽  
Fred Davies* ◽  
Ronald Lacey ◽  
Que Ngo
Keyword(s):  
Gas Exchange ◽  
Plant Growth ◽  
Life Support ◽  
Dark Respiration ◽  
Ambient Pressure ◽  
Low Pressure ◽  
High Light ◽  
Assimilation Rate ◽  
Ethylene Evolution ◽  
Process Gas

Elevated levels of ethylene occur in enclosed crop production systems and in space-flight environments—leading to adverse plant growth and sterility. There are engineering advantages in growing plants at hypobaric (reduced atmospheric pressure) conditions in biomass production for extraterrestrial base or spaceflight environments. Objectives of this research were to characterize the influence of hypobaria on gas exchange and ethylene evolution of lettuce (Lactuca sativa L. cv. Buttercrunch). Lettuce was grown under variable total gas pressures [50 and 101 kPa (ambient)]. The six chambered, modular low plant growth (LPPG) system has a Rosemount industrial process gas chromatograph (GC) for determining gas concentrations of oxygen (O2), carbon dioxide (CO2) and nitrogen (N). With the LPPG system, changes in CO2 can be tracked during the light and dark periods on a whole canopy basis, and transpirate collected as a measurement of transpiration. During short growth periods of up to seven days, growth was comparable between low and ambient pressure. However, there was a tendency for leaf tip burn under ambient pressure, in part because of higher ethylene levels. Tip burn increased under high light (600 vs. 300 μmol·m-1·s-1) and high CO2 (600 vs. 100 Pa). The CO2 assimilation rate and dark respiration tended to be higher under ambient conditions. High humidity (100%) reduced CO2 assimilation rate compared to 70% RH. Ethylene was increased by high light (600 vs. 300 μmol·m-1·s-1) and high CO2 (600 vs. 100 Pa). Ethylene was higher under ambient than low pressure. Enhanced plant growth under low pressure may be attributed to reduced ethylene production and decreased dark respiration (lower night consumption of metabolites).

scholarly journals (147) Effect of Hypobaria, Oxygen, and Carbon Dioxide on Gas Exchange, Ethylene Evolution, and Growth of Lettuce Plants for NASA Advanced Life Support Systems

HortScience ◽  
2006 ◽  
Vol 41 (4) ◽  
pp. 1059A-1059
Author(s):  
Chuanjiu He ◽  
Fred T. Davies ◽  
Ronald E. Lacey ◽  
Sheetal Rao
Keyword(s):  
Gas Exchange ◽  
Plant Growth ◽  
Biomass Production ◽  
Crop Production ◽  
Life Support ◽  
Dark Period ◽  
Ambient Pressure ◽  
Advanced Life Support ◽  
Low Pressure ◽  
Ethylene Evolution

There are engineering and payload advantages in growing plants under hypobaric (reduced atmospheric pressure) conditions in biomass production for extraterrestrial base or spaceflight environments. Objectives of this research were to characterize the influence of hypobaria on growth, gas exchange, and ethylene evolution of lettuce (Lactuca sativa L. cv. Buttercrunch). Elevated levels of the plant hormone, ethylene, occur in enclosed crop production systems and in space-flight environments—leading to adverse plant growth and sterility. Lettuce plants were grown under variable total gas pressures [25 (low) or 101 kPa (ambient)]. During short growth periods of up to 10 days, growth was comparable between low and ambient pressure plants. Regardless of total pressure, plant growth was reduced at 6 kPa pO2 compared to 12 and 21 kPa pO2. At 6 kPa pO2 there was greater growth reduction and stress with ambient (101 kPa) than low (25kPa) pressure plants. Plants at 25/12 kPa pO2 had comparable CO2 assimilation and a 25% lower dark-period respiration than 101/21 kPa pO2 (ambient) plants. Greater efficiency of CO2 assimilation/dark-period respiration occurred with low pressure plants at 6 kPa pO2. Low pressure plants had a reduced CO2 saturation point (100 Pa CO2) compared with ambient (150 Pa CO2). Low pO2 lowered CO2 compensation points for both 25 and 101 kPa plants, i.e., likely due to reduced O2 competing with CO2 for Rubisco. Ethylene was 70% less under low than ambient pressure. High ethylene decreased CO2 assimilation rate of 101/12 kPa O2 plants. The higher dark-period respiration rates (higher night consumption of metabolites) of ambient pressure plants could lead to greater growth (biomass production) of low pressure plants during longer crop production cycles.

scholarly journals (305) Influence of Hypobaria on Gas Exchange and Growth of Lettuce for Advanced Life Support Systems (ALS)

HortScience ◽  
2005 ◽  
Vol 40 (4) ◽  
pp. 1011B-1011
Author(s):  
Chuanjiu He ◽  
Fred T. Davies ◽  
Ronald Lacey
Keyword(s):  
Biomass Production ◽  
Space Flight ◽  
Crop Production ◽  
Life Support ◽  
Production Systems ◽  
Dark Respiration ◽  
Ambient Pressure ◽  
Advanced Life Support ◽  
Low Pressure ◽  
Production Cycles

There are advantages in growing plants under hypobaric (reduced atmospheric pressure) conditions in biomass production for extraterrestrial base or space-flight environments. Elevated levels of the plant hormone ethylene occur in enclosed crop production systems and in space-flight environments—leading to adverse plant growth and sterility. Objectives of this research were to characterize the influence of hypobaria on growth and ethylene evolution of lettuce (Lactuca sativa L. cv. Buttercrunch). Growth was comparable in lettuce grown under low (25 kPa) and ambient (101 kPa) total gas pressures. However, tip burn occurred under ambient, but not low pressure—in part because of adverse ethylene levels. Under ambient pressure, there were higher CO2 assimilation rates and dark respiration rates (higher night consumption of metabolites) compared to low pressure. This could lead to greater growth (biomass production) of low pressure plants during longer crop production cycles.

Hypobaria, hypoxia, and light affect gas exchange and the CO2 compensation and saturation points of lettuce (Lactuca sativa)This paper is one of a selection published in a Special Issue comprising papers presented at the 50th Annual Meeting of the Canadian Society of Plant Physiologists (CSPP) held at the University of Ottawa, Ontario, in June 2008.

Botany ◽  
2009 ◽  
Vol 87 (7) ◽  
pp. 712-721 ◽  
Author(s):  
Chuanjiu He ◽  
Fred T. Davies ◽  
Ronald E. Lacey
Keyword(s):  
Gas Exchange ◽  
Partial Pressure ◽  
Lactuca Sativa ◽  
Crop Production ◽  
Ambient Pressure ◽  
High Light ◽  
Compensation Point ◽  
Saturation Point ◽  
Low Light ◽  
Light Irradiance

There are important engineering and crop production advantages in growing plants under hypobaric (reduced atmospheric pressure) conditions for extraterrestrial base or spaceflight environments. The objectives of this research were to determine the influence of hypobaria and reduced partial pressure of oxygen (pO2) (hypoxia) under low and high light irradiance on carbon dioxide (CO2) assimilation (CA), dark-period respiration (DPR), and the CO2 compensation and CO2 saturation points of lettuce (Lactuca sativa L. ‘Buttercrunch’). Plants were grown under variable total gas pressures [25 and 101 kPa (ambient)] at 6, 12, or 21 kPa pO2 (approximately the partial pressure in air at normal pressure). Light irradiance at canopy level of the low-pressure plant growth system (LPPG) was at 240 (low) or 600 (high) µmol·m–2·s–1. While hypobaria (25 kPa) had no effect on CA or the CO2 compensation point, it reduced the DPR and the CO2 saturation point, and increased the CA / DPR ratio. Hypoxia (6 kPa pO2) and low light reduced CA, DPR, and the CA / DPR ratio. Hypoxia decreased the CO2 compensation point regardless of total pressure. Hypoxia also decreased the the CO2 saturation point of ambient-pressure plants, but had no effect on hypobaric plants. While low light reduced the CO2 saturation point, it increased the CO2 compensation point, compared with high-light plants. The results show that hypobaric conditions of 25 kPa do not adversely affect gas exchange compared with ambient-pressure plants, and may be advantageous during hypoxic stress.

Effects of container size and fruit load intensity on tomato under salt stress

2021 ◽  
Author(s):  
Kaining Zhou ◽  
Naftali Lazarovitch ◽  
Jhonathan Ephrath
Keyword(s):  
Salt Stress ◽  
Stomatal Conductance ◽  
Gas Exchange ◽  
Plant Growth ◽  
Plant Height ◽  
Stem Diameter ◽  
Rooting Depth ◽  
Assimilation Rate ◽  
Load Intensity ◽  
Fruit Load

<p>Container size and fruit load intensity are two common factors manipulated to regulate plant growth and development. As saline water is increasingly used for irrigation in arid and semi-arid regions, it is important to study effects of container size and fruit load intensity on tomato in both aboveground and belowground parts under salt stress. The experiment was conducted in a net house located in Sede Boqer Campus, Israel. Containers of four sizes (8-, 28-, 48-, and 200L with the same depth but vary in diameters), two salinity levels (1.5- and 7.5 dS m<sup>−1</sup>) and two crop load intensities (0% and 100%) were applied. Gas exchange parameters (i.e., stomatal conductance and CO<sub>2 </sub>assimilation rate), plant growth parameters (i.e., plant height and stem diameter), and root development were monitored periodically. Plant biomass and various root traits were measured at harvest. For aboveground part, results revealed that container size and salinity level significantly influenced gas exchange performance while fruit load intensity had no significant effect. Plants grown in larger containers without salt stress had higher stomatal conductance and CO<sub>2 </sub>assimilation rate. Plant height and stem diameter were significantly greater in plants grown in 200L than those in other containers despite salinity and fruit load levels. Moreover, plants grown in 200L containers exhibited significant increase of 56.3%, 152.9%, and 174.9% respectively in yield compared with those grown in 48-, 28- and 8L under salt stress. The increase magnitudes were greater when there was no salt stress: 109.0%, 430.8%, and 454.0% respectively. For belowground parts, increased container size leads to increased rooting depth. Besides, Minirhizotron data showed that in 200L containers, plants grown under low salinity without fruit developed the greatest total root length. More detailed root data will be presented.  It is concluded that container size has a pronounced effect on physiological behaviours of tomato plants. Therefore, properly increasing container size can alleviate yield reduction under saline irrigation.</p>

scholarly journals Biosynthesis Genes in Arabidopsis thaliana

HortScience ◽  
2006 ◽  
Vol 41 (4) ◽  
pp. 1059B-1059 ◽  
Author(s):  
Sheetal Rao ◽  
Scott Finlayson ◽  
Chuanjiu He ◽  
Ronald Lacey ◽  
Raymond Wheeler ◽  
...  
Keyword(s):  
Plant Growth ◽  
Ethylene Production ◽  
Life Support ◽  
Acc Oxidase ◽  
Advanced Life Support ◽  
Acc Synthase ◽  
Gene Families ◽  
Low Pressure ◽  
Primary Objective ◽  
Ambient Conditions

The NASA Advanced Life Support (ALS) System for space habitation will likely operate under reduced atmospheric pressure (hypobaria). There are engineering, safety, and plant growth advantages in growing crops under low pressure. In closed production environments, such as ALS, excessive plant-generated ethylene may negatively impact plant growth. Growth of lettuce (Lactuca sativa) in the Low Pressure Plant Growth (LPPG) system was enhanced under low pressure (25kPa), due in part to decreased ethylene production. Under reduced pO2, ethylene production decreased under low as well as ambient conditions (He et al., 2003). During hypobaria, the expression of genes encoding ethylene biosynthesis enzymes, namely ACC synthase (ACS) and ACC oxidase (ACO), is not known. The primary objective of this research was to characterize the expression of ACS and ACO genes in response to hypobaria. Three-week-old Arabidopsis was used to determine the effects of hypobaria (25 kPa) and reduced O2 (12 kPa pO2) at the molecular level. Candidate gene expression was tested using quantitative real-time PCR at different times after treatment. Under low pressure, ACO1 expression is induced in the initial 12 hours of treatment, gradually decreasing with increased exposure. At 12 kPa pO2, ACO1 was induced under ambient conditions, suggesting that plants under low pressure may be more tolerant to hypoxic stress. The mechanism for enhanced growth of lettuce under hypobaric conditions will be studied further by analysis of the ACS and ACO gene families, and stress-responsive genes, namely late-embryogenesis abundant (LEA) proteins and dehydrins.

Analysis and calculation of the process of low-pressure reverse osmosis during recycling of hygienic water

2019 ◽  
pp. 28-36
Author(s):  
Leonid S. Bobe ◽  
Nikolay A. Salnikov
Keyword(s):  
Mass Transfer ◽  
Reverse Osmosis ◽  
Life Support ◽  
Space Station ◽  
Low Pressure ◽  
Operating Pressure ◽  
Life Support System ◽  
Cleaning Agent ◽  
The Difference ◽  
Pressure Channel

Analysis and calculation have been conducted of the process of low-pressure reverse osmosis in the membrane apparatus of the system for recycling hygiene water for the space station. The paper describes the physics of the reverse osmosis treatment and determines the motive force of the process, which is the difference of effective pressures (operating pressure minus osmotic pressure) in the solution near the surface of the membrane and in the purified water. It is demonstrated that the membrane scrubbing action is accompanied by diffusion outflow of the cleaning agent components away from the membrane. The mass transfer coefficient and the difference of concentrations (and, accordingly, the difference of osmotic pressures) in the boundary layer of the pressure channel can be determined using an extended analogy between mass transfer and heat transfer. A procedure has been proposed and proven in an experiment for calculating the throughput of a reverse osmosis apparatus purifying the hygiene water obtained through the use of a cleaning agent used in sanitation and housekeeping procedures on Earth. Key words: life support system, hygiene water, water processing, low-pressure reverse osmosis, space station.

scholarly journals Heatwave frequency and seedling death alter stress-specific emissions of volatile organic compounds in Aleppo pine

Oecologia ◽  
2021 ◽  
Author(s):  
Benjamin Birami ◽  
Ines Bamberger ◽  
Andrea Ghirardo ◽  
Rüdiger Grote ◽  
Almut Arneth ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Gas Exchange ◽  
Organic Compounds ◽  
Stress Responses ◽  
Methyl Salicylate ◽  
Environmental Changes ◽  
Pinus Halepensis ◽  
Dark Respiration ◽  
Seedling Mortality ◽  
Volatile Organic

AbstractBiogenic volatile organic compounds (BVOC) play important roles in plant stress responses and can serve as stress indicators. While the impacts of gradual environmental changes on BVOCs have been studied extensively, insights in emission responses to repeated stress and recovery are widely absent. Therefore, we studied the dynamics of shoot gas exchange and BVOC emissions in Pinus halepensis seedlings during an induced moderate drought, two four-day-long heatwaves, and the combination of drought and heatwaves. We found clear stress-specific responses of BVOC emissions. Reductions in acetone emissions with declining soil water content and transpiration stood out as a clear drought indicator. All other measured BVOC emissions responded exponentially to rising temperatures during heat stress (maximum of 43 °C), but monoterpenes and methyl salicylate showed a reduced temperature sensitivity during the second heatwave. We found that these decreases in monoterpene emissions between heatwaves were not reflected by similar declines in their internal storage pools. Because stress intensity was extremely severe, most of the seedlings in the heat-drought treatment died at the end of the second heatwave (dark respiration ceased). Interestingly, BVOC emissions (methanol, monoterpenes, methyl salicylate, and acetaldehyde) differed between dying and surviving seedlings, already well before indications of a reduced vitality became visible in gas exchange dynamics. In summary, we could clearly show that the dynamics of BVOC emissions are sensitive to stress type, stress frequency, and stress severity. Moreover, we found indications that stress-induced seedling mortality was preceded by altered methanol, monoterpene, and acetaldehyde emission dynamics.

scholarly journals Salt tolerance and regulation of gas exchange and hormonal homeostasis by auxin-priming in wheat

2013 ◽  
Vol 48 (9) ◽  
pp. 1210-1219 ◽  
Author(s):  
Muhammad Iqbal ◽  
Muhammad Ashraf
Keyword(s):  
Abscisic Acid ◽  
Gas Exchange ◽  
Acid Concentration ◽  
Spring Wheat ◽  
Indoleacetic Acid ◽  
Co2 Assimilation ◽  
Assimilation Rate ◽  
Co2 Assimilation Rate ◽  
Net Co2 Assimilation Rate ◽  
Net Co2 Assimilation

The objective of this work was to assess the regulatory effects of auxin-priming on gas exchange and hormonal homeostasis in spring wheat subjected to saline conditions. Seeds of MH-97 (salt-intolerant) and Inqlab-91 (salt-tolerant) cultivars were subjected to 11 priming treatments (three hormones x three concentrations + two controls) and evaluated under saline (15 dS m-1) and nonsaline (2.84 dS m-1) conditions. The priming treatments consisted of: 5.71, 8.56, and 11.42 × 10-4 mol L-1 indoleacetic acid; 4.92, 7.38, and 9.84 × 10-4 mol L-1 indolebutyric acid; 4.89, 7.34, and 9.79 × 10-4 mol L-1 tryptophan; and a control with hydroprimed seeds. A negative control with nonprimed seeds was also evaluated. All priming agents diminished the effects of salinity on endogenous abscisic acid concentration in the salt-intolerant cultivar. Grain yield was positively correlated with net CO2 assimilation rate and endogenous indoleacetic acid concentration, and it was negatively correlated with abscisic acid and free polyamine concentrations. In general, the priming treatment with tryptophan at 4.89 × 10-4 mol L-1 was the most effective in minimizing yield losses and reductions in net CO2 assimilation rate, under salt stress conditions. Hormonal homeostasis increases net CO2 assimilation rate and confers tolerance to salinity on spring wheat.

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