Karyological Observations

Krikorian, A. D.; O'Connor, Stefania A.

doi:10.1093/oxfordjournals.aob.a086866

Cited by 51 publications

(19 citation statements)

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“…Many plant space biology experiments have shown abnormalities such as chromosomal breakage (Krikorian and O'Connor, 1984), failure to produce seed (Mashinsky et al,1994;Campbell et al, 2001), altered or nonviable embryos (Merkys and Laurinavicius, 1983), alterations in the cell wall composition and properties (Hoson et al, 2003), increased breakdown of xyloglucans (Soga et al, 2002), changes in polar auxin transport (Ueda et al, 2000), or other morphological abnormalities (Link and Cosgrove, 2000). Most plant space experiments last less than 18 days.…”

Section: Introductionmentioning

confidence: 99%

Seed-to-Seed-to-Seed Growth and Development of Arabidopsis in Microgravity

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Busse²,

Stanković³

2014

Astrobiology

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Arabidopsis thaliana was grown from seed to seed wholly in microgravity on the International Space Station. Arabidopsis plants were germinated, grown, and maintained inside a growth chamber prior to returning to Earth. Some of these seeds were used in a subsequent experiment to successfully produce a second (back-toback) generation of microgravity-grown Arabidopsis. In general, plant growth and development in microgravity proceeded similarly to those of the ground controls, which were grown in an identical chamber. Morphologically, the most striking feature of space-grown Arabidopsis was that the secondary inflorescence branches and siliques formed nearly perpendicular angles to the inflorescence stems. The branches grew out perpendicularly to the main inflorescence stem, indicating that gravity was the key determinant of branch and silique angle and that light had either no role or a secondary role in Arabidopsis branch and silique orientation. Seed protein bodies were 55% smaller in space seed than in controls, but protein assays showed only a 9% reduction in seed protein content. Germination rates for space-produced seed were 92%, indicating that the seeds developed in microgravity were healthy and viable. Gravity is not necessary for seed-to-seed growth of plants, though it plays a direct role in plant form and may influence seed reserves.

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Section: Introductionmentioning

confidence: 99%

Seed-to-Seed-to-Seed Growth and Development of Arabidopsis in Microgravity

Link

Busse²,

Stanković³

2014

Astrobiology

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“…Siliques of A. thaliana plants flown in the U.S. space shuttle (STS-54) contained empty, shrunken ovules, although 80% of the pollen grains were viable (Kuang et al, 1994). Preliminary studies revealed chromosome breakage and bridge formation in spacegrown oat and sunflower seedlings (Krikorian and O'Connor, 1984;Levine and Krikorian, 1992).…”

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confidence: 99%

Growth and Photosynthetic Responses of Wheat Plants Grown in Space

et al. 1996

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Crowth and photosynthesis of wheat (Triticum aestivum 1. cv Super DwarO plants grown onboard the space shuttle Discovery for 10 d were examined. Compared to ground control plants, the shoot fresh weight of space-grown seedlings decreased by 25%. Postflight measurements of the O, evolution/photosynthetic photon flux density response curves of leaf samples revealed that the C0,-saturated photosynthetic rate at saturating light intensities in space-grown plants declined 25% relative to the rate in ground control plants. l h e relative quantum yield of C0,-saturated photosynthetic O, evolution measured at limiting light intensities was not significantly affected. In space-grown plants, the light compensation point of the leaves increased by 33%, which likely was dueto an increase (27%) in leaf dark-respiration rates. Related experiments with thylakoids isolated from space-grown plants showed that the light-saturated photosynthetic electron transport rate from H,O through photosystems I1 and I was reduced by 28%. These results demonstrate that photosynthetic functions are affected by the microgravity environment.

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“…Recent studies in both prokaryotes and eukaryotes have shown that the spaceflight environment is mutagenic and capable of inducing various types of phenotypic mutants (Krikorian and O'Connor, 1984;Kuang et al, 1996;Mei et al, 1998;Nechitailo et al, 2005;Li et al, 2007). In plants, several studies have documented altered DNA fingerprinting patterns in individuals derived from space-flown seeds compared with their ground controls (Mei et al, 1998;Nechitailo et al, 2005;Li et al, 2007); however, in none of these cases, the nature of alterations at the DNA sequence level was characterized.…”

Section: Discussionmentioning

confidence: 99%

“…Indeed, numerous studies have reported that spaceflight is mutagenic and induces various types of phenotypic mutations and molecular changes (Krikorian and O'Connor, 1984;Kuang et al, 1996;Mei et al, 1998;Nechitailo et al, 2005;Li et al, 2007). However, except in a case of microorganism where enhanced mutation rate of both point mutations and larger insertion/deletion events were documented at the nucleotide sequence level (Yatagai et al, 2000), nature of the phenotypic mutants in eukaryotes (mainly in plants) have not been molecularly characterized.…”

Section: Introductionmentioning

confidence: 99%