The effects of CaCl2, GA3, and H2O2 priming on Isatis indigotica Fort. seed germination characteristics, seedling growth parameters, and antioxidant enzyme activities under salt stress were investigated. NaCl had an adverse effect on the germination and seedling performance of I. indigotica. However, these three priming agents alleviated salt stress by increasing the germination percentage, improving seed vigor, accelerating germination velocity, and establishing strong seedlings. The optimal concentrations were 15 g/L for CaCl2, 0.2 g/L for GA3, and 40 mm for H2O2. Seed priming treatments enhanced the activities of antioxidant enzymes in seedlings, such as superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT), under a salt environment, which reduced the oxidative injury caused by salt. Seed priming is a promising technique that can enhance the ability of I. indigotica seed germination when salt is present.

Three maize cultivars with different endosperm types (flint, semiflint, and dent maize cultivars) were studied to characterize vitreous endosperm flour properties compared with those of floury endosperm flour from the same maize kernels. Vitreous endosperm flour had higher amylose and protein contents, and lower starch content, higher percentage of large starch granule, bigger mean diameter of starch granule, higher iodine capacity, higher trough viscosity and final viscosity and setback, lower swelling power, lower peak viscosity and breakdown, and higher peak time and pasting temperature than the counterpart floury endosperm flour. X‐ray diffraction analysis indicated typical A‐pattern for starches of vitreous and floury endosperm flours. Floury endosperm flour showed the presence of greater crystallinity and higher enthalpy change ( ∆Hgel ) than vitreous endosperm flour for three cultivars. Retrogradation enthalpy ( ∆Hret ) and retrogradation percentage ( R ) of vitreous and floury endosperm flours ranged from 6.23 to 7.92 J/g and 52.72% to 73.62%, and from 5.46 to 6.45 J/g and 45.70% to 56.58%, respectively. In conclusion, vitreous and floury endosperm flours had significantly different physicochemical properties. Results of this study provide a foundation for better and valid utilization of different endosperm section during grain processing.

Low planting density and irrational nitrogen (N) fertilization are two common practices in conventional cropping of smallholder maize production in Huanghuaihai region of China. A 2-year field experiment was carried out to study the effects of N application and planting density on maize phenology, dry matter accumulation, profit, yield, N uptake and efficiency indices. The experiments included three N application levels (120 kg ha−1, N1; 180 kg ha−1, N2; 240 kg ha−1, N3) and three planting densities (60,000 plants ha−1, D1; 75,000 plants ha−1, D2; 90,000 plants ha−1, D3). Increasing N input and planting density delayed the physiological maturity and enhanced dry matter accumulation. Comparing with the traditional N3 level, grain yield and profit were kept stable at N2 level and decreased at N1 level, partial factor productivity of applied N (PFPN) and nitrogen efficiency ratio (NER) were increased with the decreasing of N level. Comparing with the traditional D1 density, grain yield, profit and PFPN were increased at D2 density and then kept stable at D3 density, NER was kept stable at D2 density and then decreased at D3 density. Based on the predicted maximum profit, the optimal combinations of N application and planting density were 199 kg ha−1 and 81,081 plants ha−1 in 2017, and 205 kg ha−1 and 84,782 plants ha−1 in 2018. The two optimal combinations had an increase of 17.6% for grain yield, 39.8% for PEPN, 3.6% for NRE than the traditional N3D1 treatment. Therefore, an appropriate combination of increased planting density with reduced N application could enhance profit and nitrogen use of summer maize in Huanghuaihai region of China.