Accumulation and role of some organic and inorganic osmotica under salinity in pearl millet

Accumulation of various osmotica plays a crucial role in the maintenance of cell water balance under stressfull conditions. This study was initiated to find out the role of some osmotica in various parts of differentially salt tolerant pearl millet lines at growth stages. The inorganic osmotica included soluble nitrate (SN) and soluble phosphate (SP), while organic ones soluble sugars (SS) and free proline (FP). There was a greater accumulation of SS and SP in the young leaf and root of and DB- 5, while Ghana white behaved otherwise. On the other hand, a reverse trend of accumulation was evident for FP and SN. The role of SP and SN as osmotica was further confirmed from the ratio of SP/ total P and SN/ total N in various parts. SP/ total P was greater for young leaf and root of Togo followed by DB-5, while that of SN/ total N was greater for old of these lines and young leaf of Ghana White. The establishment of various correlations between Na+ and CI- content and inorganic and organic osmotica revealed that SS and SP are the real contributors to the maintenance of water balance of the while the accumulation of SN and FP appear to be the effect of ion toxicity.