[Alleviation of salt stress during maize seed germination by presoaking with exogenous sugar].

The maize variety Kenyu 6 was used to study the effects of exogenous glucose (Glc) and sucrose (Suc) on salt tolerance of maize seeds at germination stage under 150 mmol · L(-1) NaCl treatment. Results showed that under salt stress condition, 0.5 mmol · L(-1) exogenous Glc and Suc presoaking could promote seed germination and early seedling growth. Compared with the salt treatment, Glc presoaking increased the shoot length, radicle length and corresponding dry mass up to 1.5, 1.3, 2.1 and 1.8 times, and those of the Suc presoaking treatment increased up to 1.7, 1.3. 2.7 and 1.9 times, respectively. Exogenous Glc and Suc presoaking resulted in decreased levels of thiobarbituric acid reactive substances (TBARS) and hydrogen peroxide (H2O2) content of maize shoot under salt stress, which were lowered by 24.9% and 20.6% respectively. Exogenous Glc and Suc presoaking could increase the activities of superoxide dismutase (SOD), ascorbate peroxidase (APX), glutathione peroxidase (GPX), glutathione reductase (GR) and induce glucose-6-phosphate dehydrogenase (G6PDH) activity of maize shoot under salt stress. Compared with the salt treatment. Glc presoaking increased the activity of SOD, APX, GPX, GR and G6PDH by 66.2%, 62.9%, 32.0%, 38.5% and 50.5%, and those of the Suc presoaking increased by 67.5%, 59.8%, 30.0%, 38.5% and 50.4%, respectively. Glc and Suc presoaking also significantly increased the contents of ascorbic acid (ASA) and glutathione (GSH), ASA/DHA and GSH/GSSG. The G6PDH activity was found closely related with the strong antioxidation capacity induced by exogenous sugars. In addition, Glc and Suc presoaking enhanced K+/Na+ in maize shoot by 1.3 and 1.4 times of water soaking salt treatment, respectively. These results indicated that exogenous Glc and Suc presoaking could improve antioxidation capacity of maize seeds and maintain the in vivo K+/Na+ ion balance to alleviate the inhibitory effect of salt stress on maize seed germination.

[Biological treatment of nitrobenzene and aniline in interactional inhibitory system through the selective bioaugmentation].

The mixed wastewater containing aniline and nitrobenzene was treated through combining adsorption and bioaugmentation. Tests were conducted to investigate the inhibition of aniline and nitrobenzene on another biodegradation, the condition of adsorption separation, the biodegradation process through bioaugmentation and the variation of resin performance. The experimental results showed that aniline and nitrobenzene interactional inhibited another biodegradation. Adjusting pH to 4 and absorption velocity to 110 mL/h, the mixed wastewater of aniline (330 mg/L) and nitrobenzene (44 mg/L) passed through the adsorption column containing 10 mL resin NDA-150 (7.2 g). In the adsorption effluent the nitrobenzene concentration was not more than 4 mg/L and aniline concentration had no change. The residual aniline in effluent could be degraded through bioaugmentation. During this process about 597 mg nitrobenzene had been adsorbed by resin, in which 224 mg could be desorbed and biodegraded through bioaugmentation. The volumetric loading to nitrobenzene was 315 mg/(L x d). Through bioregeneration the adsorption capacity of resin NDA-150 could be recovered partly, which extent was limited by the bioavailability to nitrobenzene. After about 70 d recycled experiment the performance of resin NDA-150 was stable.