The Effect of NaCl Salinity on Germination, Growth of Tomato Sprit and ES-30502 Rootstocks, and Nutrient Acquisition in Nutrient Culture

This study aim at investigating the tolerance of two tomato rootstock (Sprit and ES- 30502) widely speared in Syria and used for crafting some tomato hybrids grown in green houses for different salinity levels (0- 25- 50- 75- 100- 150 mM NaCl). The results show that the germination of rootstock Sprit seeds was not influenced by high salinity 150 mM despite a delay of 1-2 days compared with the control. A reduction of 15% was observed in the rootstock ES-30502 at 100 and 150 mM NaCl salinity levels, in addition to slower percentage rate of germination. In contrast, the effect of salinity on the development of the radical and rootlet was more pronounced in Sprit compared to ES- 30502. Salinity decreased the growth of both shoots and roots, and also decreased nutrient acquisition in both rootstocks, but to a lesser degree in ES-30502. The uptake of K was not greatly affected and concentrations in shoot remained normal. The concentrations of Ca and Mg were also not affected by salinity. The most pronounced effect of salinity was on nitrogen effect (NO3) which was reduced greatly in both rootstocks. This was accompanied by accumulation of free NO3 ions in the shoot tissue (58 and 45 % of total N uptake at salinity level of 150 mM). It is most likely that toxicity of Na and Cl ions, and consequent osmotic changes in cell tissue led to slower nitrate reductase activity (NRA) and accumulation of NO3.

The effect of different concentrations of NaCl in seeds germination and early seedling growth of Lactuca plants cv. Kabous and Shinshar

This investigation was conducted at the laboratories of Horticulture Departments, Faculty of Agriculture to study the effect of different levels of salinity (NaCl) in the rate and the percentage of seed germination of lettuce, Lactuca sativa L. varieties: Shinshar and Kabous and to determine the seedling response to these levels of salinity with relative to root length, the length of the cold, fresh and dry weight of seedlings. NaCl was used at 0, 50, 100, 150 and 200 mM/l. Resulted showed that a gradual increase in salinity concentrations caused a gradual decline in all indicators studied in both cultivars. However, the plants of Kabous variety were less sensitive to the salinity and also higher than in the indicators studied for seedlings (rate of germination and percent, stems and roots length, fresh and dry weight of seedlings) under salt stress conditions.

The effect of salinity on proline and carbohydrate contenets in three bread wheat genotypes (Triticum aestivum L.) in vegetative growth stage in hydroponic cultures

This study was carried out in 2009-2011, in the laboratories of science faculty - Tishreen University. The seeds of three genotypes: Sham8, Sakha8,AUS 29639 of bread wheat were planted in hydroponic cultures irrigated with Hoagland liquid in a growth chamber to compare the effect of three salt concentrations (0, 100,200 mm of NaCl) on proline and carbohydrate contents in three growth stages 21, 28, 35 of the experiment. There was an increase of proline and carbohydrate contents in all cultivars with increased salinity during the three growth stages of plants. Proline contents increased in Sham8 with low rates compare with Sakha8, AUS 29639. It increased in Sakha8 with the increase of salinity which reached 348% in the third growth stage in concentration 200 mm NaCl, while Proline concentration reached the highest value in AUS 29639 (524%). The carbohydrate content reached the highest value in Sakha8 in NaCl concentration 200 in the first growth stage (238070%) compared with the control, and (204.34%) in third stage in NaCl concentration 200mM compare with the control. The results of the study indicate the superiority of Sakha8, AUS 29639 in salt tolerance through accumulating suitable rates of proline and carbohydrates. AUS 29639 was more resistant to salt stress than Sakha8. We may use these results later in other physiological and genetical studies.