Effect of Root-zone Hypoxia on Growth and Endogenous Hormones of Muskmelon Xylem Sap

摘要

The growth and endogenous hormone contents of muskmelon xylem sap were studied in aeroponic culture by growing their roots in containers comprising of 5%, 10% and 21% O2 (control), respectively. The results showed that plant height, the biomasses of roots, shoots and fruit were markedly inhibited at 30 days of root-zone hypoxia stress compared with those in the contrastive plants. Moreover, 5% O2 stress had more drastic impacts than 10% O2. The contents of indoleacetic acid (IAA), gibberellins (GA3) and zeatin (ZT) decreased in root xylem saps, whereas the content of abscisic acid (ABA) increased. In conclusion, when the root-zone oxygen concentration fell to 10% and 5%, the synthesis and transport of endogenous hormones were affected, leading to the inhibition of its growth and fruit development.