Effects of NaCl-Induced and Salts Mixture Salinity on Leaf Proline and Growth of Tomato in Symbiosis with Arbuscular Mycorrhizal Fungi

摘要

Soil salinity is a environmentally hazardous factor which gradually extends in agricultural lands and diminishes plant growth. Mycorrhizal symbiosis can affect yield and plant growth parameters in saline condition. The experiment was carried out in a glasshouse as randomized complete block design with two factors including fungi in three levels, G0(without fungi), Gi(Glomus interaradices) and Gm(Glomus mosseae) and salinity in eight levels. Two types of salinity were applied including four levels of NaCl (S_1-S_4), S =1.2, S_2=4, S_3=6.5 and S_4=8 dS/m and four levels of salt mixture (S_5-S_8), S_5=l .2, S_6=4, S_7=6.5 and S_8=8 dS/m.The composition of salt mixture was NaCl,CaCl_2, MgSO_4 and Na_2SO_4 at ratio of 1:38:43:20 (w/v),respectively. The seedlings were inoculated separately with two fungi species. Control plants (without inoculation ) were planted in a sterilized sand. After two months, the inoculated plants were transferred to the pots containing four kg sterilized sand and salinity treatments in nutrient solution were initiated gradually. The results showed significant increase in shoot dry weight, leaf area, root colonization percent (RCP), fruit weight and leaf proline concentration of mycorrhizal than non-mycorrhizal plants (p < 0.05). Although there was not significant difference between Gm and Gi, they increased (p < 0.05) tomato yield by 10% and 16% compared to non-mycorrhizal plants, respectively. Regardless of salt composition, the effects of salinity levels were significant on plant measured parameters (p < 0.001). Dry weight of shoot and root, RCP and fruit weight were decreased by increasing salinity levels, but they had not significant differences between the comparable levels in two types of salinity. Proline concentration in leaf was significantly higher (p < 0.05) at third and fourth levels of NaCl than same levels of salts mixture.