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Growth and lignification in seedlings exposed to eight days of microgravityFour-day-old pine seedlings and mung bean and oat seeds were prepared for flight on the third Space Transport System Mission (STS-3). The seedlings and seeds were planted in six mini-growth chambers (two chambers per species) which were placed in a plant growth unit (PGU). Another set of seedlings and seeds was prepared and placed in another PGU as the 1 g control. The flight PGU was positioned in the orbiter mid-deck locker area about 11 h prior to launch. The pine seedlings and germinating mung bean and oat seeds were exposed to 194 h of microgravity. The PGU was received at a temporary laboratory about 75 min post-landing. Plants were observed, photographed and the atmospheric gases analyzed at the landing site. The plants were then brought to our Houston laboratory where they were measured and analyzed for lignin and protein content and for phenylalanine ammonia-lyase (PAL) and peroxidase activities. Flight seedlings were shorter than the controls in all three species. Twenty-five to 40 per cent of the mung bean and oat roots were growing upward, and the mung beans showed signs of disorientation. Flight mung beans showed a significant reduction in lignin content in comparison to the controls, and PAL and peroxidase activities were reduced in flight pine seedlings. The results generally support the postulate that lignin synthesis is reduced in near-weightlessness and show other interesting findings.
Document ID
20040089599
Document Type
Reprint (Version printed in journal)
Authors
Cowles, J. R.
(University of Houston TX 77004, United States)
Scheld, H. W.
Lemay, R.
Peterson, C.
Date Acquired
August 21, 2013
Publication Date
January 1, 1984
Publication Information
Publication: Annals of botany
Volume: 54
Issue: Suppl 3
ISSN: 0305-7364
Subject Category
Life Sciences (General)
Funding Number(s)
CONTRACT_GRANT: NAS2-11165
CONTRACT_GRANT: NSG 9042
Distribution Limits
Public
Copyright
Other
Keywords
Flight Experiment
NASA Program Flight
Non-NASA Center
STS-3 Shuttle Project
manned
NASA Discipline Number 00-00
short duration
NASA Discipline Plant Biology
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