ABSTRACT
Soil salinization is a serious
problem leading to ecological degradation.Melia azedarach is highly
salt-tolerant, and its application to saline-alkali land is a promising
strategy for restoring degraded lands. In this study, we analyzed the
soil properties and metabolome of M. azedarach roots grown in
low- (< 3 g/kg; L), medium- (5~8 g/kg; M), and
high- (> 10 g/kg; H) salinity soils to explore the
amelioration effect and adaptation mechanism of M. azedarach to
soils with differential salinity. Cultivation of M. azedarach was
associated with a decrease in the concentration of Na+and increases in organic matter content and alkaline phosphatase and
urease activities in the rhizosphere soil. The metabolome analysis
revealed that a total of 382 (ESI+) and 277 (ESI-) differential
metabolites (DEMs) were detected. The number of DEMs in roots rose with
increased soil salinity, such as sugars and flavonoids in H vs. L, and
amino acids in M vs. L. The most up-regulated DEMs were
13-S-hydroxyoctadecadienoic acid, 2’-Deoxyuridine and
20-hydroxyleukotriene B4. Combined analysis of soil properties andM. azedarach DEMs indicated that alkaline phosphatase activity
was positively correlated with traumatic acid concentration. Taken
together, these results indicate that M. azedarach has the
potential to reduce soil salinity and enhance soil enzyme activity, and
it can adapt to salt stress by regulating metabolites like sugars, amino
acids, and flavonoids. This study provided a basis for
understanding the mechanism underlying the adaptation of M.
azedarach to saline-alkali soil and its amelioration.
Key words: Adaptation; In-situ restoration; Melia
azedarach ; Root metabolome; Salt stress; Soil salinization