Inhibition of pear fruit ripening by mannose
1Department of Horticulture and Forestry, Rutgers University, New Brunswick, New Jersey 08903.
Plant Physiology
|September 1, 1987
Summary
Mannose application delays pear fruit ripening by inhibiting ethylene production and respiration. This effect is linked to mannose 6-phosphate accumulation, which depletes inorganic phosphate and ATP, but is reversible.
Area of Science:
- Plant Physiology
- Biochemistry
- Horticulture
Background:
- Fruit ripening involves complex biochemical processes including ethylene evolution and respiration.
- Mannose is a sugar that can influence plant metabolic pathways.
Purpose of the Study:
- To investigate the effect of mannose on pear fruit ripening.
- To elucidate the biochemical mechanisms underlying mannose-induced inhibition of ripening.
Main Methods:
- Vacuum infiltration of mannose into pear fruit.
- Measurement of ethylene evolution, respiration rates, and levels of key metabolites (M6P, Pi, G6P, ATP).
- Application of mannose analogs and related compounds.
Main Results:
- Mannose infiltration delayed softening, ethylene evolution, and respiration in pear fruit.
- Inhibition correlated with mannose phosphorylation to mannose 6-phosphate (M6P) and subsequent depletion of inorganic phosphate (Pi) and ATP.
- Metabolism of M6P reversed inhibition; M6P itself inhibited ethylene production and respiration in tissue disks.
- Mannose analogs showed varied effects, with alpha-methylmannoside mimicking mannose's inhibitory action.
Conclusions:
- Mannose inhibits pear fruit ripening through mechanisms involving M6P accumulation and Pi depletion.
- M6P may exert toxicity, contributing to the inhibition of ripening processes.
- The observed effects are dose-dependent and reversible, highlighting the dynamic metabolic interplay.
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