تحت دو سطح تنش شوري )BEAT VULGARISL.( بررسي صفات رشد پنج واريته چغندرقند

The study of growth traits of five sugar beet cultivars under two levels of salt stress

In this experiment, the effect of two levels of salinity (0 mM and 200 mM NaCl and CaC12 in 5 to 1 molar ratio) on early growth stages and dry matter partitioning of five cultivars of sugar beet (Beta vulgaris L. cvs Madison, 7233-P12, 7233-P107 PC-7233 and CI) was studied. Although there was no significant difference in some growth reduction, respectively in comparison with their controls after 35 days of treatmet. However, the growth of CI cultivar was recovered better than Madison during 15 days of the saline treatment. In all cultivars, particularly in 7233-P12 relative growth rate (RGR) and net assimilation rate (NAR) were significantly reduced by salinity within the first 32 days of salt treatment. The highest and lowest reduction in shoot water content was observed in Madison and CI cultivars, respectively, in comparison with control within the first 35 days of salt treatment. Higher water loss in Madison may act by concentrating solute in cell sap, there by reducing the need for synthesis of metabolically expensive organic as well as reducing the need for Na+ uptake for osmotic adjustment. The root dry matter of sugar beet reduced by 81.96%, while the dry matter of lamina and petiole plus decreased by 61 and 66% respectively. The pattern of dry matter partitioning to different of plant was changed by salt stress and the allocated dry matter to the root was reduced by 10%.