Determination of inorganic ions and organic solutes in plant
tissues
The green assimilating branches of H. ammodendron were collected
at the five sites in May and July and oven-dried at 70°C for at least 48
h to a constant mass. The dried samples were ground in a ball
mill MM400 (Retsch, Germany) into they were uniformly fine powders and
freeze dried for preservation. For the extraction of soluble sugar and
starch, we followed Anderegg et al., 2012. After the digestion of
sucrose and starch, the concentrations of each was measured using the
phenol-sulfuric acid method and a UV spectrophotometer (colorimetric
method, UV-2401PC, Shimadzu Corporation, Japan). A ninhydrin
colorimetric method was used for proline concentration determinations
with a UV spectrophotometer (Abraham, Hourton-Cabassa, Erdei, &
Szabados, 2010; Song et al., 2006). The Na+concentrations were determined using pulsed flame photometer detection
(Song et al., 2006; Jenway Ltd., UK).