Effect of Root-zone Hypoxia on Endogenous Hormones of Muskmelon in Aeroponic Culture

摘要

The study investigated the effects of root-zone hypoxia on the endogenous hormone contents of muskmelon during the fruit development.Muskmelon seedlings were cultured in an airtight aeroponic culture system and grew in containers under root-zone hypoxia (comprising of 5％ and 10％ O2) and normoxia (21％ O2).The hormone contents in different organs were measured.The results showed that under root-zone hypoxia,indoleacetic acid (IAA),gibberellins (GA3) and zeatin (ZT) decreased differentially in roots and leaves,whereas abscisic acid (ABA) increased.The differences in IAA,GA3,ZT and ABA at 5％ O2 condition reached extremely significant level compared to those under normoxia.Under hypoxia,IAA contents in roots and leaves decreased significantly compared to those of normoxia at the 10th day of hypoxia.The contents of GA3 and ZT in roots reduced significantly to minimum at the 10th day of hypoxia.ABA contents in roots and leaves under hypoxia significantly increased compared to those at the 10 day of normoxia.In conclusion,when the root-zone oxygen concentration fell to 10％ and 5％,IAA,GA3,and ZT synthesis and transport capacity decrease rapidly,while ABA contents in various organs increase significantly.Inhibition of plant growth and fruit development are closely related to the production and unbalanced distribution of hormones in muskmelon.