In this paper, a fractal model for capillary flow through a single tortuous capillary with roughened surfaces in fibrous porous media is derived. The determined imbibition height and imbibition mass of capillary rise are in satisfying agreement with the existing models reported in the literature. It is found that the imbibition height and imbibition mass of capillary decreases with increasing relative roughness. Besides, it is observed that the equilibrium time in a single tortuous capillary with roughened surfaces decreases with an increase in relative roughness. In addition, it is seen that the imbibition height and imbibition mass of capillary rise increases with imbibition time. With the proposed fractal model, the physical mechanisms of capillary flow through a single tortuous capillary with roughened surfaces in fibrous porous media are better elucidated. One advantage of our fractal analytical model is that it contains no empirical constant, which is usually required in previous models.

In this paper, fluid transport through fibrous porous media is studied by the fractal theory with a focus on the effect of surface roughness of capillaries. A fractal model for Kozeny–Carman (KC) constant and dimensionless permeability of fibrous porous media with roughened surfaces is derived. The determined KC constant and dimensionless permeability of fibrous porous media with roughened surfaces are in good agreement with available experimental data and existing models reported in the literature. It is found that the KC constant of fibrous porous media with roughened surfaces increases with the increase of relative roughness, porosity, area fractal dimension of pore and tortuosity fractal dimension, respectively. Besides, it is seen that the dimensionless permeability of fibrous porous media with roughened surfaces decreases with increasing relative roughness and tortuosity fractal dimension. However, it is observed that the dimensionless permeability of fibrous porous media with roughened surfaces increases with porosity. With the proposed fractal model, the physical mechanisms of fluids transport through fibrous porous media are better elucidated.

Salinity is one of the most important factors that reduce the growth and antioxidant defense of plants. A controlled pot experiment was conducted to investigate the ameliorative effects of jasmonic acid (JA) priming (0, 5, and 10 mM) and humic acid (HA) (0, 3, and 6 g HA kg−1 soil) amendment on antioxidant enzymes and salt tolerance of forage sorghum seedling (Sorghum bicolor L.) grown under three salinity conditions (0, 100, and 200 mM NaCl). Salinity stress reduced emergence seedling index (ESI), promptness index (PI), emergence stress tolerance index (ESTI), dry weight stress tolerance index (DWSTI), and the activities of the peroxidase (POD) and catalase (CAT) enzymes. The activity of superoxide dismutase (SOD) and malondialdehyde (MDA) content increased with salinity. Application of JA positively affected all parameters except CAT and MDA. Humic acid significantly increased all measured parameters except ESTI, DWSTI, and SOD activity. At the 200 mM NaCl level, JA and HA increased CAT, POD, SOD, ESI, DWSTI, ESTI, PI, and MDA as compared with the control. The application of HA at 6 g kg−1 soil decreased SOD and ESI relative to the control at high salinity. The application of 10 mM JA combined with HA at 6 g kg−1 soil was most effective in alleviating salinity stress. Therefore, the combined application of JA and HA on forage sorghum may improve salt tolerance and increase antioxidant enzymes that alleviate damages caused by salinity stress. Core Ideas Application of jasmonic acid and humic acid (HA) mitigated salinity stress. Jasmonic acid (JA) and HA increased the antioxidant enzymes. Applying a combination of JA and HA at high levels of salinity improved salt tolerance.

Salinity is a major abiotic stress limiting crop growth and reducing grain yield. In recent years, little progress was made in salt‐tolerant cultivation techniques. Therefore, a controlled experiment was conducted to study the effects of nitrogen management (NM) on growth, antioxidant ability, and yield performance of salt‐tolerant rice (Oryza sativa L.) under salinity stress. Three salinity levels (0‰ as control; 0.75‰, 4.3 dS m−1; and 1.5‰, 7.7 dS m−1) and four levels of NM (tillering fertilizer/panicle initiation fertilizer = 7:3, 6:4, 5:5, and 4:6) were arranged in this study. Under salinity stress, plant height, tiller number, fresh weight, grain yield, panicle, spikelets per panicle, grain weight, and soluble sugar content in stem were significantly decreased. In contrast, antioxidant parameters of superoxide dismutase, peroxidase, and catalase were significantly increased. Grain filling percentage and sucrose content were slightly changed. Compared to the control, grain yield was reduced by 45.6%, 34.8%, 60.4%, and 46.7% at the ratio of 7:3, 6:4, 5:5, and 4:6 NM at 0.75‰ salinity level, and 73.5%, 59.7%, 74.8%, and 61.7% at 1.5‰ salinity level, respectively. The highest yield was generated by 6:4 NM at both the 0.75‰ and 1.5‰ salinity level, and the lowest by 4:6 and 5:5. However, NM could obviously alleviate the inhibition effects of salinity stress and improve antioxidant ability of rice. Among them, 6:4 NM performed the best alleviation effects, followed by 7:3 and 5:5 NM. This study suggests that the appropriate NM can effectively alleviate salinity stress and increase grain yield.

Sweet sorghum (Sorghum bicolor [L.] Moench) is a potential feedstock crop in biomass energy development, and is much more resistant to saline soils than crops. Healthy seed germination is critical for the growth cycle of plants, and determines the establishment of seedlings and subsequent crop production. High salinity conditions can result in difficulty for seed germination and delays the germination period. So, screening salt-tolerant genotypes and method for healthy seed germination under salinity stress are vital to crop production and food security. Therefore, a controlled study was conducted to explore the interactive amendment effects of exogenous gibberellic acid (GA3) and salinity on seed germination process of sweet sorghum. Seeds were presoaked in different levels of GA3 water solutions (0, 144, 288, and 576 μM) and then cultivated in gradient NaCl solutions (0, 50 and 100 mM). The effects of salinity and external GA3 on seed water uptake and germination characteristics were investigated. Compared with the effects of 0 μM GA3 at 0 mM NaCl, slight salt stress of 50 mM NaCl improved the cumulative water uptake, germination and germination index, but high salinity level of 100 mM NaCl significantly inhibited these germination traits. However, either 100 mM NaCl or 576 μM GA3 had significantly negative effects on seed cumulative water uptake, cumulative germination, germination index, and length of germ and radicle. The appropriate concentration of GA3 prominently relieved salt stress and improved the seed germination of sorghum seeds, and the optimum concentration for seed germination of sweet sorghum was 288 μM GA3 at each salinity level.