Effects of O/sub 2/ concentration on rice seedlings
The ability of rice, wheat, and oat seedlings to germinate and grow as the O/sub 2/ concentration was lowered to zero was compared. The germination of rice was completely unaffected by O/sub 2/ supply, whereas that of oats and wheat was strongly retarded at levels below 5% O/sub 2/. In contrast to the coleoptiles of oats and wheat and to roots of all three species where growth was progressively diminished as the O/sub 2/ concentration was lowered, that of the rice coleoptile was progressively increased. However, the dry weight and content of protein, sugars, and cellulose were all depressed in the rice coleoptile in anoxia, and the levels of several respiratory enzymes, particularly those of mitochondria, were also much lower than those of the coleoptiles grown in air. In 1% O/sub 2/, the growth of the rice coleoptile was similar to that in air. The effect of ethanol concentration on germination and growth of rice was measured. Coleoptile growth was reduced when the ethanol concentration exceeded 40 millimolarity, and root growth was somewhat more sensitive. Coleoptiles of all three species grown in air were transferred to N/sub 2/ and ethanol accumulation was measured over 24 hours. The rate of ethanol accumulation in oats was close to that in rice, and in all three species the amounts of ethanol lost to the surrounding medium were those expected from simple diffusion from the tissue. The ability of the rice coleoptile to grow in anoxia is apparently not due to a particularly low rate of ethanol formation or to unusual ethanol tolerance. Any explanation of the success of rice in anoxia must encompass the much lower rate of ATP synthesis than that in air and account for the biochemical deficiencies of the coleoptile.
- Research Organization:
- Univ. of California, Santa Cruz
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 6238117
- Journal Information:
- Plant Physiol.; (United States), Vol. 71
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
OXYGEN
BIOLOGICAL EFFECTS
ANAEROBIC CONDITIONS
ATP
BIOCHEMISTRY
BIOLOGICAL ACCUMULATION
COLEOPTILE
COMPARATIVE EVALUATIONS
ETHANOL
GERMINATION
METABOLISM
OATS
PLANT GROWTH
RICE
ROOTS
SEEDLINGS
SENSITIVITY
WHEAT
ALCOHOLS
CEREALS
CHEMISTRY
ELEMENTS
GRASS
GROWTH
HYDROXY COMPOUNDS
NONMETALS
NUCLEOTIDES
ORGANIC COMPOUNDS
PLANTS
560303* - Chemicals Metabolism & Toxicology- Plants- (-1987)