The objective of this study was to characterize and quantify five commonly occurring flavonoids (quercetin, luteolin, apigenin, myricetin, and kaempferol) in storage roots and leaves of 10 sweetpotato [Ipomoea batatas L. (Lam.)] accessions: SC1149, ‘Excel’, ‘Vardaman’, ‘Hernandez’, ‘Picadito’, ‘Porto Rico’, ‘GA90-16’, PI531116, NC98-608 (Covington), and ‘Beauregard’ (B94-14-G2). The flavonoids were present in varying amounts (quercetin comprised greater than 79% and 55% of the mean flavonoid content in sweetpotato leaf and root samples, respectively) and were found to be more concentrated in the leaves (0.65% to 2.76% dry weight) than in the storage roots (0.27% to 1.69% dry weight). The results indicate significant variability in flavonoid content among different sweetpotato accessions, suggesting that there is the potential for genetic manipulation of sweetpotato to influence flavonoid content and profile through traditional breeding or biotechnological approaches.

Drought is a world-spread problem seriously influencing grain production and quality, the loss of which is the total for other natural disasters, with increasing global climate change making the situation more serious. Rice is the staple food for more than 23% of world population, so rice anti-drought physiology study is of importance to rice production and biological breeding for the sake of coping with abiotic and biotic conditions. Much research is involved in this hot topic, but the pace of progress is not so large because of drought resistance being a multiple-gene-control quantitative character. On the other hand, stress adaptive mechanisms are quite different, with stress degree, time course, materials, soil quality status and experimental plots, thus increasing the complexity of the issue in question. Additionally, a little study is related to weedy rice.In order to investigate the effects of drought stress on germination and early seedling growth of weedy rice (Oryza sativa f. spontanea L.) and cultivated rice (Oryza sativa L.), polyethyleneglycol-6000 (PEG-6000) are used to generate -1.33MPa and 0MPa water stress in a laboratory condition (28±3°C). Complete randomized design with three replications is used in the study. After 10 days of germination, shoot length, the longest root length, root fresh weight, root dry weight, shoot fresh weight, shoot dry weight and root numbers are measured; germination percentage, and root to shoot ratio are calculated. Germination index (GI), shoot length stress index (SLSI), root length stress index (RLSI) and dry matter stress index (DMSI) are used to evaluate the response of different genotypes to PEG-induced water stress. Results of ANOVA analysis show that responses of weedy rice accessions and cultivated rice varieties to water stress are significant different, demonstrating the germplasm of weedy rice and cultivated rice are diverse which enables us to screen the germplasm tolerant to drought stress.

The production of 2-keto-L-gulonic acid (2-KGA) during the conversion from L-sorbose to 2-KGA in the two-step fermentation of vitamin C can be improved by using an efficient companion strain Bacillus subtilis A9 to facilitate the growth of Ketogulonicigenium vulgare and the production of 2-KGA. Two optimization models, namely response surface methodology (RSM) and artificial neural network (ANN), were built to optimize the medium components for mixedculture fermentation of 2-KGA. The root mean square error, R 2 and the standard error of prediction given by the ANN model were 0.13%, 0.99% and 0.21%, respectively, while the RSM model gave 1.89%, 0.84% and 2.9%, respectively. This indicated that the fitness and the prediction accuracy of the ANN model were higher than those of the RSM model. Furthermore, using genetic algorithm (GA), the input space of the ANN model was optimized, predicting that the maximum 2-KGA production of 72.54 g¢L ¡1 would be obtained at the GA-optimized concentrations of the medium components (L-sorbose, 92.5 g¢L ¡1 ; urea, 10.2 g¢L ¡1 ; corn steep liquor, 16 g¢L ¡1 ; CaCO 3 , 3.96 g¢L ¡1 ; MgSO 4 , 0.28 g¢L ¡1 ). The 2-KGA production experimentally obtained using the ANNÀGA-designed medium was 71.21 § 1.53 g¢L ¡1 , which was in good agreement with the predicted value. The same optimization process may be used to improve the production during bacterial mixed-cultures fermentation by changing the fermentation parameters.

This study sought to define what attributes of sweetpotatoes are most critical to textural qualities of their fried chips for effective selection of specialty cultivars. It compared texture-predicting fracturability of fried chips prepared from either structurally intact or disrupted slices of 13 cultivars; analyzed major attributes of these sweetpotatoes, including starch contents and properties, dry matter contents, and structure-related penetration resistances (measured using an adapted penetration test); and evaluated correlational relationships between these attributes of sweetpotatoes and fracturability of fried chips. The study found that lower dry matter (<22.6% F.W.) and starch contents (<10% F.W.), and lower gelatinization temperatures of starch in sweetpotatoes generally resulted in a more favorable fracturability (lower peak break force) of fried chips. However, contrary to potato, total dry matter content is not the sole determinant of textural qualities of fried sweetpotato chips; instead, structurerelated attributes of sweetpotatoes appear to have a greater impact. Partial structural disruptions of sweetpotato slices by blanching effectively improved fracturability of fried chips in all analyzed cultivars, and by ~40% in eight of the 13 cultivars. Furthermore, the degree of structural penetrability of sweetpotatoes, as indexed by penetration resistances, showed very significant correlations with fracturability of fried chips.

As we all know, the degree of farmland immersion is affected by many factors such as soil moisture content, natural pore ratio, saturation, soil lithology and so on. However, the conventional submergence assessment method only uses the relative relationship between the depth of phreatic water and the rising height of capillary water to judge the degree of submergence, which is obviously unreasonable. Therefore, in this paper, a method of farmland immersion evaluation based on trigonometric whiteness weight function grey clustering is proposed. The physical properties of soil, surface soil lithology of vadose zone and groundwater level elevation are included in the evaluation index system, and the degree of submergence is classified, and then the weight function is constructed to determine the degree of submergence hazard of each observation point in the immersion area. Case study shows that the method is reasonable and feasible for farmland immersion evaluation.