Akaline, saline and mixed saline-alkaline stresses induce physiological and morfo-anatomical changes in Lotus tenuis shoots.

PAZ, ROSALÍA CRISTINA; REINOSO, HERMINDA; ESPASANDÍN, FABIANA; GONZALEZ ANTIVILO, FRANCISCO ALBERTO; SANSBERRO, PEDRO A.; ROCCO, RUBÉN ANÍBAL; RUIZ, OSCAR A.; MENÉNDEZ, ANA B.

PLANT BIOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2014 vol. 16 p. 1042 - 1049

1435-8603

Saline, alkaline and mixed, saline alkaline conditions frequently co occur in soil. In this work, we compared these plant stresses sources on the legume species Lotus tenuis, regarding their effects on shoot growth, and leaf and stem anatomy. In addition, we aimed at gaining insight on the plant physiological status of stressed plants. We performed pot experiments with four treatments, control without salt addition (pH=5.8; EC=1,2 dS m-1) and three stress conditions: saline (100 mM NaCl, pH=5.8; EC=11 dS m-1), alkaline (10 mM NaHCO3 , pH=8.0, EC= 1.9 dS m-1), and mixed salt?alkaline (10 mM NaHCO3 plus 100 mM NaCl, pH=8.0, EC= 11 dS m-1). Neutral and alkaline salts produced a similar level of growth inhibition on L. tenuis shoots, whereas their mixturexacerbated their detrimental effects. Our results showed that none of the analyzed morpho anatomical parameters categorically differentiated one stress from the other. However, NaCl and NaHCO3 derived stresses could be discriminated by different extents and/or directions of changes in some of the anatomical traits. For example, alkalinity led to increased ostiolar opening area, conversely to NaCl treated plants, where a stomatal aperture reduction was observed. Likewise, plants from the mixed saline alkaline treatment characteristically lacked of a palisade mesophyll in their leaves. The stem cross section and vessels areas, as well as the number of vascular bundles in the sectioned stem were reduced in all treatments. A rise in the number of vessel elements in the xylem was registered in NaCl treated plants, but not in those treated exclusively with NaHCO3.