Zhiguo Su

The role of salicylic acid in response of two rice cultivars to chilling stress

Two rice (Oryza sativa L.) cultivars differing in chilling sensitivity, Changbaijiu (chilling-tolerant) and Zhongjian (chilling-sensitive) were pre-treated with 0.5, 1.0 and 2.0 mM salicylic acid (SA) for 24 h before chilling at 5°C for 1 d. Chilling induced SA accumulation, particularly conjugated SA in both leaves and roots of the two rice cultivars. After SA administration, SA accumulated in the roots of both cultivars at a concentration-dependent manner, whereas only a slight increase was observed in their leaves. Conjugated SA accounted for most of the increase. The beneficial effect of SA treatment on protecting rice seedlings from chilling injury was not observed at any concentration in either cultivar. Pre-treatment with SA even decreased their chilling tolerance confirmed by increased electrolyte leakage and lipid peroxidation. Further, most of the activities of antioxidant enzymes decreased or remained unchanged in leaves and roots of SA pre-treated seedlings after chilling. These results implied that down-regulation of antioxidant defence might be involved in the reduction of chilling tolerance in SA-pre-treated plants.

Efficient decolorization and deproteinization using uniform polymer microspheres in the succinic acid biorefinery from bio-waste cotton (Gossypium hirsutum L.) stalks.

Bio-waste cotton (Gossypium hirsutum L.) stalks were converted into succinic acid by simultaneous saccharification and fermentation (SSF) using Actinobacillus succinogenes 130Z. After 54 h SSF at 40 °C and pH 7.0, the production of succinic acid was 63 g/L, with 1.17 g/L/h productivity and 64% conversion yield. After SSF, a simple method for the decolorization and deproteinization of crude SSF broth was developed through adsorption tests of polystyrene (PSt) microspheres. Under optimized conditions (5% PSt loading (w/v), pH 4.0, 60 °C and adsorption time of 40 min), the ratios of decolorization, deproteinization and succinic acid loss ratios were 96.6, 84.5 and 4.1%, respectively. The method developed will provide a potential approach for large-scale production of succinic acid from the biomass waste.