Studies On Salt And Drought Tolerance Appraisal And Physiological And Biochemical Analysis Of Transgenic Rice With DREB1A Gene

In order to improve the tolerance of salt and drought in hybrid rice and ensure the national food security, the salt and drought tolerance of 12 lines of transgenic male sterile rice 4008S with DREB1A gene were studied in this paper, the main results are as follows:(1) 15% PEG-6000 were used as water-stress agent to simulate drought conditions, the transgenic male sterile lines with DREB1A gene and the check rice plants (non-transgenic 4008S,the donor plant of transgenic lines) were stressed for 7 days. Their radicle and shoot length were measured and the data were analyzed by DPS software.The results indicated that the radicle and shoot length of transgenic lines were higher than that of the control except line 08H1172.Among them, the transgenic lines 08H1164,08H1181,08H1182,08H1185 showed significant deviation in radicle and shoot length compared with the control.(2) The content of proline, the relative electronic conductivity and the MDA content of leaves of rice at seedling stage were analyzed after treatments of 0.5% Nacl and 0.9% Nacl, respectively. Results of statistic analysis showed that the salt tolerance of the transgenic rice with DREB1A were better than the non-transgenic rice, which indicated that the DREB1A gene could improve the rice performance of salt-tolerance.(3)All transgenic rice lines with DREB1A were treated with salt stress and results indicated that:the final values and growth rate of relative electronic conductivity in leaves of 08H1170,08H1174,08H1180 and 08H1185 were lower than other trangenic rice lines;the accumulation value and growth rate of proline in 08H1174,08H1185, and 08H1170, were higher than the others of transgenic rice lines; the final values and growth rate of MDA content in 08H1174,08H1163,08H1185 and 08H1180 after salt stress were lower than other trangenic rice lines.According to physiological and biochemical results,08H1174,08H1180 and 08H1185 with DREB1A were considered to be better lines against salt sress.(4) The physiological index of transgenic rice at heading stage were determined.After 7 days of drought stress, the proline content of transgenic 4008S were higher than the non-transgenic, while the electric conductivity and the MDA content of transgenic 4008S were lower than the non-transgenic.The statistic analysis was conducted by the DPS 3.0, and the results indicated that drought resistance of transgenic rice with DREB1A were significanty different from the control.Therefore, the resistances under drought stress of transgenic rices were stronger than the control,which indicated that the DREB1A gene can improve the performance of rice drought resistance.(5) Among different strains of transgenic rice, after stressed treatment, the final value of relative electric conductivity in leaves and the rate of increase of 08H1174,08H1185,08H1180 were lower than other strains; the value of proline accumulation and the rate of increase of 08H1174,08H1180,08H1185,08H1164,08H1170 were higher than other strains; the MDA content and the rate of increase of 08H1174,08H1185,08H1170 were lower than other strains.Synthesizing the physiological index, the drought tolerance of 08H1174,08H1185 were stronger.(6) Considering comprehensively from the previous analysis the order of salt tolerance and drought resistance capacity of transgenic strains are: 08H1174>08H1185>08H1170>08H1180>08H1163>08H1164>08H1171>08H1172>0 8H1181>08H1184>08H1173>08H1182.Therefore, the transgenic strain 08H1174 has the strongest salt tolerance and drought resistance.