Abstract
In this experimentation, we intend to place in a prominent and show up the attitude
of String bean, plants (Phaseolus vulgaris L) aged six weeks stressed under increasing
concentrations salinity NaCl at 100 meq.l-1 , 200 meq.l-1 and with NaCl+CaCl2 at 100
meq.l-1 et 150 meq.l-1. These parameters are evaluated in this experimentation are, the
determination of the soluble proteins at the level of leafs, stems and roots, by the method of
BRADFORD (1976), the activity of the nitrate reductase at the level of the aerial, and the
underground parts (ROBEN et al.,1981) and the counting of the nodules number by each
plant, and also their fresh weight.
The obtained results show that; the soluble proteins content varies according to the
organ, the saline concentration and the salt type. Generally, leafs are much more affected
by salinity, especially by NaCl, with a progressive fall of their soluble proteins content in
proportion of the increase the saline concentration. By against at the level of roots, we
noted that an important accumulation has been produced during the salinity application,
while the variation at the level of stems is poor discovered.
The nitrate reductase activity has more on leafs than it has on roots among the non
stressed plants. The impact of increasing concentrations of NaCl on String bean is
reflected by an important fall of the enzyme activity at the level of leafs, this activity is
completely cancelled during the application of a concentration of 200 meq.l-1.While this
activity is stimulated at the level of roots with augmentations that could reach 300% and
500% respectively. Among plants which are nourished at 100 meq.l-1 and 200 meq.l-1 of
NaCl. On the other side, the application of salinity using NaCl +CaCl2 Restorers the ANR
of leafs and roots.
The salinity with NaCl restrains the expansion of nodules in number and in fresh
weight, this impact appears clearly when the saline concentration raised at 200 meq.l-1
where nodulation is blocked. The addition of CaCl2 has incidences on nodulation; in fact,
the nodules number by plant increase simultaneously with the augmentation of the saline
concentration. Somewhere else, the nodules fresh weight has benefited of the addition of
CaCl2, where a light augmentation has been signalized.
Key words: salinity, nitrate reductase activity, soluble proteins, nodules, root, aerial parts,
bean (Phaseolus vulgaris L).