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 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 (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.

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.

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.

Canopy structure and imaging geometry may create unique problems during spectral reflectance measurements of crop canopies in bioregenerative advanced life support systems

2007 ◽  
Vol 6 (2) ◽  
pp. 109-121
Author(s):  
Andrew C. Schuerger ◽  
Kenneth L. Copenhaver ◽  
David Lewis ◽  
Russell Kincaid ◽  
George May
Keyword(s):  
Remote Sensing ◽  
Plant Growth ◽  
Spectral Reflectance ◽  
Life Support ◽  
Support Systems ◽  
Canopy Structure ◽  
Advanced Life Support ◽  
Sensing System ◽  
Plant Canopies ◽  
Reflectance Measurements

AbstractHuman exploration missions to the Moon or Mars might be helped by the development of a bioregenerative advanced life-support (ALS) system that utilizes higher plants to regenerate water, oxygen and food. In order to make bioregenerative ALS systems competitive to physiochemical life-support systems, the ‘equivalent system mass’ (ESM) must be reduced by as much as possible. One method to reduce the ESM of a bioregenerative ALS system would be to deploy an automated remote sensing system within plant production modules to monitor crop productivity and disease outbreaks. The current study investigated the effects of canopy structure and imaging geometries on the efficiency of measuring the spectral reflectance of individual plants and crop canopies in a simulated ALS system. Results indicate that canopy structure, shading artefacts and imaging geometries are likely to create unique challenges in developing an automated remote sensing system for ALS modules. The cramped quarters within ALS plant growth units will create problems in collecting spectral reflectance measurements from the nadir position (i.e. directly above plant canopies) and, thus, crop canopies likely will be imaged from a diversity of orientations relative to the primary illumination source. In general, highly reflective white or polished surfaces will be used within an ALS plant growth module to maximize the stray light that is reflected onto plant canopies. Initial work suggested that these highly reflective surfaces might interfere with the collection of spectral reflectance measurements of plants, but the use of simple remote sensing algorithms such as 760/685 band ratios or normalized difference vegetation index (NDVI) images greatly reduced the effects of the reflective backgrounds. A direct comparison of 760/685 and NDVI images from canopies of lettuce, pepper and tomato plants indicated that unique models of individual plants are going to be required to properly assess the health conditions of canopies. A mixed model of all three plant species was not effective in predicting plant stress using either the 760/685 or NDVI remote sensing algorithms.

scholarly journals (299) Comparison of Growth of Salad Crops under ISS Baseline Environmental Conditions in Mixed Crop versus Monoculture Hydroponic Systems

HortScience ◽  
2005 ◽  
Vol 40 (4) ◽  
pp. 1010A-1010
Author(s):  
Sharon Edney ◽  
Jeffrey Richards ◽  
Matthew Sisko ◽  
Neil Yorio ◽  
Gary Stutte ◽  
...  
Keyword(s):  
Environmental Conditions ◽  
Crop Production ◽  
Time Course ◽  
Production Efficiency ◽  
Life Support ◽  
Space Station ◽  
Space Vehicle ◽  
Advanced Life Support ◽  
Cropping System ◽  
Mixed Crop

Development of a crop production system that can be used on the International Space Station, long duration transit missions, and a lunar/Mars habitat, is a part of NASA's Advanced Life Support (ALS) research efforts. Selected crops require the capability to be grown under environmental conditions that might be encountered in the open cabin of a space vehicle. It is also likely that the crops will be grown in a mixed-cropping system to increase the production efficiency and variety for the crew's dietary supplementation. Three candidate ALS salad crops, radish (Raphanus sativus L. cv. Cherry Bomb II), lettuce (Lactuca sativa L. cv. Flandria) and bunching onion (Allium fistulosum L. cv. Kinka) were grown hydroponically as either monoculture (control) or mixed-crop within a walk-in growth chamber with baseline environments maintained at 50% relative humidity, 300 μmol·m-2·s-1 PPF and a 16-hour light/8-hour dark photoperiod under cool-white fluorescent lamps. Environmental treatments in separate tests were performed with either 400, 1200, or 4000 μmol·mol-1 CO2 combined with temperature treatments of 25 °C or 28 °C. Weekly time-course harvests were taken over 28 days of growth. Results showed that none of the species experienced negative effects when grown together under mixed-crop conditions compared to monoculture growth conditions.

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