Changes in growth, biochemical components and antioxidant genes expression in rice seedling (Oryza sativa L.) cultivar IR64 under salt stress

One of abiotic stresses that affects rice growth is salinity. Plant must develop adaptation process which includes morphological, biochemical and molecular changes. This research aimed to evaluate morpho-biochemical and molecular responses of rice ‘IR64’ to several levels of salinity stress at seedling stage. Seedlings of ‘IR64’ were grown in a hydroponic system and treated with different levels of salinity stress (4dSm-1, 6dSm-1 and 12dSm-1) for seven days. Responses were recorded on the final day of salt treatments. Gene expression analyses were done by semi-quantitative RT-PCR. RNA was extracted using RNase plant mini kit (Qiagen) and cDNA was synthesized using GoSript™ Reverse Transcription System (Promega). Results showed that shoot height and fresh weight decreased under salt stress. At plants treated with salt, the chlorophyll contents were lower than that of control plants, while MDA levels were higher in salt treated plants. Semiquantitative PCR for MnSOD1and cCu/ZnSOD1 revealed that MnSOD1 and cCu/ZnSOD1expressions increased under salt stress which indicated oxidative stress defence, with the highest expression at 4dSm-1and 6dSm-1 treatment, respectively.