تغییر الگوی توزیع قندهای محلول و یون های معدنی در گیاهچه های برنج رشد یافته در شرایط شور

In order to investigate of effect of salinity (NaCl) on soluble sugars and mineral ions concentrations in salt tolerant (IR651) and sensitive (IR29) rice (Oryza sativa L.) genotypes, a factorial based on a completely randomized design was carried out in greenhouse of physiology division of Agricultural Biotechnology Research Institute of Iran (ABRII) in 2006. Seedlings were grown in Youshida nutrient solution and NaCl stress was imposed in two levels including 0 and 100 mM at 28 days after sowing. Samples were collected from youngest leaves, leaf sheaths and roots of each plant separately at 72 and 240 hours after salinization then dry weight and concentration of Na+, K+, Ca2+, Mg2+, Mn2+ P and total soluble sugars and Na+/K+ was separately determined for each part. Results showed that under stress condition, significant reduction was occurred in dry matter of both cultivars. Na+, Cl- and total soluble sugars (TSS) concentration was increased under stress and salt tolerant was able to accumulate higher levels of Na+ and Cl- in roots to prevent toxic effect in shoot. K+ concentration was decreased with salinity and Na+/K+ ratio in shoot of IR29 was higher than IR651 while in root was lower. There was a negative correlation between Na+ with Ca2+ and Mg2+. Salt stress caused to reduction in Mn2+ concentration but P concentration showed no regular changes during stress period. This experiment showed that there was direct relation between shoot Na+ and Cl- with salt tolerance in studied genotypes. Salt tolerance in IR651 probably refers to ability of this genotype to prevent of salt accumulation in upper parts of the root and preserves lower shoot Na+/K+ ratio.