PT  - JOURNAL ARTICLE
AU  - Voigt, E. L.
AU  - Caitano, R. F.
AU  - Maia, J. M.
AU  - Ferreira-Silva, S. L.
AU  - De Macêdo, C. E. C.
AU  - Silveira, J. A. G.
TI  - Involvement of cation channels and NH&lt;sub&gt;4&lt;/sub&gt;&lt;sup&gt;+&lt;/sup&gt;-sensitive K&lt;sup&gt;+&lt;/sup&gt; transporters in Na&lt;sup&gt;+&lt;/sup&gt; uptake by cowpea roots under salinity
DP  - 2009 Dec 1
TA  - Biologia plantarum
PG  - 764--768
VI  - 53
IP  - 4
AID - 10.1007/s10535-009-0140-x
IS  - 
AB  - Na&lt;sup&gt;+&lt;/sup&gt; accumulation was investigated in the roots of 11-d-old cowpea [Vigna unguiculata (L.) Walp.] plants. The relative contribution of different membrane transporters on Na&lt;sup&gt;+&lt;/sup&gt; uptake was estimated by applying Ca&lt;sup&gt;2+&lt;/sup&gt;, K&lt;sup&gt;+&lt;/sup&gt;, NH&lt;sub&gt;4&lt;/sub&gt; &lt;sup&gt;+&lt;/sup&gt;, and pharmacological inhibitors. Na&lt;sup&gt;+&lt;/sup&gt; accumulation into the root symplast was decreased by half in the presence of 1 mM Ca&lt;sup&gt;2+&lt;/sup&gt; and it was almost abolished by 100 mM K&lt;sup&gt;+&lt;/sup&gt;. The inhibitory effect of external NH&lt;sup&gt;4+&lt;/sup&gt; on Na&lt;sup&gt;+&lt;/sup&gt; accumulation was more pronounced in the roots of NH&lt;sub&gt;4&lt;/sub&gt; &lt;sup&gt;+&lt;/sup&gt;-free growing plants. Na&lt;sup&gt;+&lt;/sup&gt; accumulation was reduced about 73 % by 0.1 mM flufenamate and it was almost blocked by 2 mM quinine. In addition, 20 mM tetraethylammonium and 1.0 mM Cs&lt;sup&gt;+&lt;/sup&gt; decreased Na&lt;sup&gt;+&lt;/sup&gt; accumulation by 28 and 30 %, respectively. These results evidenced that low-affinity Na&lt;sup&gt;+&lt;/sup&gt; uptake by cowpea roots depends on Ca&lt;sup&gt;2+&lt;/sup&gt;-sensitive and Ca&lt;sup&gt;2+&lt;/sup&gt;-insensitive pathways. The Ca&lt;sup&gt;2+&lt;/sup&gt;-sensitive pathway is probably mediated by nonselective cation channels and the Ca&lt;sup&gt;2+&lt;/sup&gt;-insensitive one may involve K&lt;sup&gt;+&lt;/sup&gt; channels and to a lesser extent NH&lt;sub&gt;4&lt;/sub&gt; &lt;sup&gt;+&lt;/sup&gt;-sensitive K&lt;sup&gt;+&lt;/sup&gt; transporters.