Plants grown in phosphorus-deprived solutions often exhibit disruption of water transport due to reduction in root hydraulic conductivity (Lpr). To uncover the relationship between root Lpr and water permeability coefficient (Pf) of plasma membrane and the role of aquaporins, we evaluated Pf of plasma membrane and also PIP-type aquaporin gene expression in tobacco (Nicotiana tabacum L.) plant roots after seven days P-deprivation. The results showed significant reduction in sap flow rate (Jv) and osmotic root hydraulic conductivity (Lpr-o) in P-deprived roots. These effects were reversed 24 h after P-resupplying. Interestingly, the Pf of root protoplasts was 57% lower in P-deprived plants compared with P-sufficient ones. The expression of NtPIP1;1 and NtPIP2;1 aquaporins did not change significantly in P-deprived plants compared with P-sufficient ones, but the copy number of NtAQP1 increased significantly in P-deprived plants. P-deprivation did not change Lpr-o significantly in antisense NtAQP1 plants. Taken together, these findings suggest that P-deprivation may play an important role in modulation of root hydraulic conductivity by affecting Pf in transcellular pathway of water flow across roots and aquaporins. Finally, we concluded that dominant water transport pathway under P-deprivation was transcellular one.
- Nicotiana tabacum
- osmotic permeability coefficient
- osmotic root hydraulic conductivity
- phosphorus deprivation
- water relation
ASJC Scopus subject areas
- Plant Science