PubMed Health⌕ Search
Home/Archive/PubMed

PubMed · 11540197

Seedling growth and development on space shuttle.

J Cowles·R LeMay·G Jahns
View original source ↗Export metadata ↓

Abstract

Young pine seedlings, and mung bean and oat seeds were flown on shuttle flights, STS-3 and STS-51F, in March, 1982 and July/August, 1985, respectively. The plant growth units built to support the two experiments functioned mechanically as anticipated and provided the necessary support data. Pine seedlings exposed to the microgravity environment of the space shuttle for 8 days continued to grow at a rate similar to ground controls. Pine stems in flight seedlings, however, averaged 10 to 12% less lignin than controls. Flight mung beans grew slower than control beans and their stems contained about 25% less lignin than control seedlings. Reduced mung bean growth in microgravity was partly due to slower germination rate. Lignin also was reduced in flight oats as compared to controls. Oats and mung beans exhibited upward growing roots which were not observed in control seedlings. Chlorophyll A/B ratios were lower in flight tissues than controls. The sealed PGCs exhibited large variations in atmospheric gas composition but the changes were similar between flight and ground controls. Ethylene was present in low concentrations in all chambers.

Explore related subjects

AvenaChlorophyllCycadopsidaEnvironment, ControlledEthylenesFabaceaeGerminationHypocotylLigninPlant Growth RegulatorsPlant RootsPlant ShootsPlant StemsPlants, MedicinalSpace FlightWeightlessnessNASA Discipline Plant BiologyNon-NASA CenterComparative StudyJournal Article

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

J Cowles, R LeMay, G Jahns. 1994. Seedling growth and development on space shuttle.. https://doi.org/10.1016/0273-1177(94)90273-9

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed2026

Functional Characterization of the Oat (Avena sativa L.) TCP Transcription Factor AsTCP38 Reveals Its Role in Low-Nitrogen Stress Tolerance.

Nitrogen limitation restricts plant growth, development, and yield in crops and forage species. Although TCP transcription factors are implicated in diverse abiotic-stress responses, the functions of most TCP genes in oat remain unclear. Here, we cloned and characterized the AsTCP38 gene, which is 1215 bp long and encodes a 405-amino-acid protein. The predicted protein contains a conserved TCP domain and shares its highest sequence similarity with Arabidopsis thaliana (A. thaliana) AtTCP15. The AsTCP38 protein localized to the nucleus, and promoter analysis identified cis-elements associated with light, hormone, and stress responses. We generated AsTCP38-overexpressing A. thaliana and wheat plants and screened an oat leaf yeast cDNA library for candidate interacting proteins. In these heterologous overexpression lines, AsTCP38 overexpression was associated with greater abscisic acid (ABA) sensitivity and improved seedling growth under low-nitrogen conditions. Changes in antioxidant-enzyme activities, nitrogen-metabolism-related enzyme activities, and endogenous hormone contents were also observed. Together, these findings suggest that AsTCP38 may participate in low-nitrogen responses and provide a basis for further functional studies in oat. Direct regulatory targets and the contribution of AsTCP38 to low-nitrogen adaptation in oat remain to be established.

Avena↗
PubMed2025

Global genomic population structure of wild and cultivated oat reveals signatures of chromosome rearrangements.

The genus Avena consists of approximately 30 wild and cultivated oat species. Cultivated oat is an important food crop, yet the broader genetic diversity within the Avena gene pool remains underexplored and underexploited. Here, we characterize over 9000 wild and cultivated hexaploid oat accessions of global origin using genotyping-by-sequencing and explore population structure using multidimensional scaling and population-based clustering methods. We also conduct analyses to reveal chromosome regions associated with local adaptation, sometimes resulting from large-scale chromosome rearrangements. We report four distinct genetic populations within the wild species A. sterilis, a distinct population of cultivated A. byzantina, and multiple populations within cultivated A. sativa. Some chromosome regions associated with local adaptation are also associated with confirmed structural rearrangements on chromosomes 1A, 1C, 3C, 4C, and 7D. This work provides evidence suggesting multiple polyploid origins, multiple domestications, and/or reproductive barriers amongst Avena populations caused by differential chromosome structure.

Avena↗
PubMed2006

An attempt to identify recombinants between two sobemoviruses in doubly infected oat plants.

Recombination in RNA viruses is considered to play a major role as a driving force in virus variability to counterbalance loss in fitness that can be due to the accumulation of detrimental mutations. Studies on mixed infections are pertinent for understanding the role of recombination in virus evolution. They also provide important baseline information for studying the biosafety of plants expressing viral sequences. To investigate the possibility of RNA recombination occurrence between two sobemoviruses under little or no selection pressure, we co-infected test plants with Cocksfoot mottle virus (CfMV) and Ryegrass mottle virus (RGMoV). CfMV and RGMoV were selected because of their overlapping host range and geographical distribution. First, symptom development of both viruses in barley (Hordeum vulgare) and oat (Avena sativa) was examined. Both viruses generated quite strong infection symptoms in oat, but synergism was not detected. RGMoV was lethal for barley, whereas CfMV infection in barley was nearly symptomless. RT-PCR analysis revealed 100% infection with both viruses in oat but not in barley. Therefore, an RNA recombination study of CfMV and RGMoV was performed in oat. 105 plants were co-inoculated with both viruses and putative recombinational hot spot regions were screened for recombination events by RT-PCR analysis at a sensitivity level down to 0.1-100 pg of viral genomic RNA. No recombination events between the two sobemoviruses were detected.

Avena↗