TITLE:
Hypoxia-Responsive Root Hydraulic Conductivity Influences Soybean Cultivar-Specific Waterlogging Tolerance
AUTHORS:
Yutaka Jitsuyama
KEYWORDS:
Aquaporin, Hypoxia, Root Hydraulic Conductivity, Root Morphology, Soybean, Waterlogging Tolerance
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.8 No.4,
March
30,
2017
ABSTRACT: Excess soil moisture induces hypoxic conditions and
causes waterlogging injury in soybean [Glycine
max (L.) Merr.]. This study investigated the mechanism underlying the
development of waterlogging injury. Nine Japanese soybean cultivars with
varying degrees of waterlogging tolerance were grown in a hydroponic system for
14 days under hypoxic conditions. Shoot and root biomasses and root hydraulic
conductivity were measured at an early vegetative stage for plants under control
and hypoxic conditions. Root morphological traits and intramembrane aquaporin
proteins were also analyzed. The tolerance of each cultivar to field
waterlogging was based on biomass changes induced by the hypoxia treatment.
Root hydraulic conductivity responses to hypoxia were associated with changes
in total dry weight, leaf dry weight, and leaf area. The effects of hypoxic
conditions on root hydraulic conductivity were also represented by the changes
in root morphology, such as total root length, thick-root length, and number of
root tips. Additionally, a 32.3 kDa aquaporin-like protein seemed to regulate
root hydraulic conductivity. Our
results from a hydroponic culture suggest that the soybean cultivar-specific
responses to hypoxic conditions in the rhizosphere reflect fluctuations in
hydraulic conductivity related to root morphological or qualitative changes.