In order to investigate the influence mechanism of pH level on the growth and development of rice and nutrient uptake under different nitrogen forms, rice cultivar Guanghui 751 was grown with five pH treatments (pH 3.5, 4.5, 5.5, 6.5, and 7.5) to study the effects on the biomass accumulation, root morphology, and nutrient uptake of rice under ammonium-nitrogen and nitrate-nitrogen conditions hydroponically. The results showed that under ammonium-nitrogen conditions, the highest rice biomass accumulation was found at pH 6.5 treatment; compared with the pH 3.5 treatment, the shoot and whole-plant biomass accumulation increased by 146.6% and 142.5%, respectively. Plant height and maximum root length increased significantly; total root length, root surface area, and root volume increased by 612.6%, 317.8%, and 147.1%, respectively. The uptake of nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), copper (Cu), zinc (Zn), iron (Fe), and manganese (Mn) increased by 159.5%, 114.3%, 181.9%, 241.4%, 124.4%, 74.9%, 173.4%, 366.2%, and 3058.0%, respectively. Under nitrate-nitrogen conditions, the highest rice biomass accumulation was found at pH=4.5 treatment; compared with the pH=3.5 treatment, the shoot, root, and whole-plant biomass accumulation increased by 36.7%, 49.6%, and 38.6%, respectively. Plant height and maximum root length increased significantly; total root length, root surface area, and root volume increased by 129.9%, 83.0%, and 47.5%, respectively. The uptake of N, P, K, Ca, Mg, Cu, Zn, Fe, and Mn increased by 40.0%, 27.7%, 51.0%, 78.5%, 71.2%, 53.9%, 292.1%, 1449.5%, and 695.1%, respectively. In conclusion, the optimum pH values for rice under ammonium-nitrogen and nitrate-nitrogen conditions were 6.5 and 4.5, respectively. Under their respective optimum pH conditions, ammonium-nitrogen and nitrate-nitrogen primarily increased rice biomass accumulation by promoting root growth and development and increasing nutrient uptake.

To address the issues of unreasonable chemical fertilizer management, low fertilizer use efficiency, and escalating environmental risks in the maize production areas of Inner Mongolia, field plot experiments were conducted in two typical production areas, namely the black soil region of Northeast China and the Tumochuan Plain. Six treatments were established: no nitrogen control (CK), 100% chemical fertilizer (M0), and organic fertilizer replacing 25% (M25), 50% (M50), 75% (M75), and 100% (M100) of chemical nitrogen, to clarify the effects of different substitution ratios on maize yield, dry matter accumulation, fertilizer use efficiency, and nitrogen (N), phosphorus (P), and potassium (K) nutrient uptake. The results showed that the M25 treatment significantly increased maize yield, with an increase of 4.69%-36.80% compared with other treatments. The M0 treatment exhibited the highest dry matter accumulation of various organs during the early growth stages of maize; however, the M25 treatment showed a distinct advantage from the large bell-mouth stage to maturity. The M25 treatment promoted the uptake of N, P, and K nutrients and enhanced their utilization efficiency; the partial productivity of fertilizer in M25 was 2.77%-50.51% higher than those of other treatments. In conclusion, the response of maize to organic fertilizer substitution in the Tumochuan Plain was superior to that in the Black Soil Region of Northeast China, and replacing 25% of chemical nitrogen with organic fertilizer can achieve a synergistic improvement in maize yield and fertilizer use efficiency.

To clarify the regulatory effects of a polyaspartic acid (PASP) combined with chitosan (CTS) on soil moisture content, tobacco plant and root growth and development, and tobacco leaf quality in the arid tobacco area of Bijie, field experiments were conducted using Yunyan 87. Different concentrations of PASP and CTS (CK: same amount of water; T1: 3.0 kg/ha PASP+0.3 kg/ha CTS; T2: 3.0 kg/ha PASP+0.6 kg/ha CTS; T3: 6.0 kg/ha PASP+0.3 kg/ha CTS; T4: 6.0 kg/ha PASP+0.6 kg/ha CTS) were applied. Soil and root indexes, growth and development parameters and quality indexes of flue-cured tobacco leaves were measured at different growth stages. The results showed that compared with other treatments, T3 treatment significantly increased soil moisture content. At the rosette stage, the moisture content of the shallow soil layer increased by 15.01% and that of deep soil layer increased by 10.16% compared with CK. T4 treatment significantly increased the number of lateral roots and adventitious roots, as well as root volume and root activity, by 34.07%, 29.12%, 25.70% and 29.56% respectively compared with the CK. The combined application of PASP and CTS significantly promoted growth, development, and dry matter accumulation of flue-cured tobacco, with higher concentrations leading to more obvious effects. Compared with CK, the leaf area and stem circumference of T4 treatment increased by 18.3% and 12.3% respectively, and the dry matter accumulation increased by 26.04%. The chemical composition, sensory and appearance quality of tobacco leaves were improved to varying degrees. The improvement effect of T2 treatment was the most significant, with increases of 10.36%, 7.76% and 7.30% respectively, compared with the CK. The quality evaluation of tobacco leaves was 7.57% higher than that of CK. The combined application of PASP and CTS can effectively increase the soil moisture content, promote the root development of flue-cured tobacco, and improve leaf quality. The optimal treatment (3.0 kg/ha PASP+0.6 kg/ha CTS) alleviated the decline in yield and quality of flue-cured tobacco caused by drought in Bijie.

This study used wild Solanum torvum Swartz. as rootstock and cultivated eggplant Solanum melongena L. Yunqie 9 as scion. The grafting method was cleft grafting. The structure of graft union at 0, 2, 4, 6, 8, 10, and 12 days after grafting was observed, and physiological indicators such as phenylalanine ammonia lyase (PAL), peroxidase (POD), superoxide dismutase (SOD), and soluble protein (SP) were measured to study the tissue structure and physiological characteristics during healing process after eggplant grafting. The results showed that the healing process of grafting between S. torvum Swartz. and Yunqie 9 could be divided into four stages, including isolation layer and callus formation stage (0-4 d), callus division and proliferation connection stage (5-7 d), cambium connection stage (8-9 d), vascular tissue differentiation and formation stage (10-12 d). The physiological indicators measured within 12 days after grafting showed that the changes in physiological characteristics of grafted seedlings and self-grafted seedlings were basically consistent. Among them, PAL activity showed an overall downward trend, SOD activity showed a “V” shaped change of first decreasing and then increasing, while POD activity and SP content showed an “M” shaped change. In addition, there were significant changes in most physiological indicators at four days after grafting; After six days, the SOD activity of all treatments showed an overall increase, and the increasing trend of SOD activity in grafted seedlings was more pronounced, with a difference of 19 times between the highest and lowest values; During the 6th to 8th days, the SP content of grafted seedlings rapidly increased and reached its highest value on the 8th day, which was 5.6 times the lowest value. In summary, the healing process between S. torvum Swartz. and Yunqie 9 could be basically completed 12 days after grafting, and the key healing time points might be 4, 6, and 8 days after grafting.

Fertilizer management, especially the precise application of panicle fertilizer, has a significant impact on rice yield, quality, and nitrogen use efficiency (NUE). To determine a reasonable panicle fertilizer ratio and application leaf-age stage for the rice-growing region along the Yellow River in Henan Province, this study used rice variety Bianjing 5 as the experimental material. At a nitrogen application rate of 277.5 kg/ha, the effects of two nitrogen fertilizer management modes—the conventional mode (with panicle fertilizer applied at the 2nd and 1st leaf stages from the top) and the precise delayed mode (with panicle fertilizer applied at the 4th and 3rd leaf stages from the top)—combined with silicon and zinc fertilizer on the yield, grain quality, and NUE of japonica rice were investigated. The results showed that both the precise delayed nitrogen mode and the application of silicon and zinc fertilizers had significant yield-increasing effects, with increments ranging from 3.9% to 13.2%. The precise delayed nitrogen mode improved yield by increasing the effective panicle number, improving the panicle-forming rate and grain number per panicle, while silicon and zinc supplementation improved yield by increasing grain number per panicle and 1000-grain weight. The precise delayed nitrogen mode combined with silicon and zinc application significantly increased the milled rice rate and head rice rate, reduced the chalky grain rate and chalkiness, and effectively improved the appearance and processing quality of the rice. Furthermore, the precise delayed nitrogen mode significantly improved nitrogen uptake efficiency, physiological nitrogen efficiency, nitrogen agronomic efficiency, and nitrogen partial productivity, while silicon and zinc application significantly enhanced nitrogen agronomic efficiency and nitrogen partial factor productivity. In conclusion, the precise delayed nitrogen mode combined with silicon and zinc fertilization contributes to the construction of a healthy population of japonica rice in the rice-growing region along the Yellow River in Henan Province, achieving synergistic improvement in yield, grain quality, and nitrogen use efficiency.

Using 19 quinoa varieties from Hebei and Xinjiang as experimental materials, the total polyphenol and total flavonoid contents of quinoa sprouts during 21-49 d were analyzed, and their antioxidant activities were evaluated by DPPH (1,1-diphenyl-2-picrylhydrazyl) and ABTS [2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid)] methods. The results showed that with the change of growth period, plant height and fresh weight of quinoa sprouts increased significantly; the total polyphenol and total flavonoid contents showed an overall downward trend; and the antioxidant activity also changed accordingly and was significantly positively correlated with the total polyphenol and total flavonoid contents. Combined with the results of cluster analysis, it was found that when the quinoa varieties Y1-Y10 from Hebei Province grew to 35 d, the total polyphenol (10.38-12.71 mg GAE/g DW) and total flavonoid (21.92-26.28 mg RE/g DW) contents were relatively high, and they exhibited certain antioxidant activities (DPPH scavenging activity: 11.65-15.64 mg TE/g DW; ABTS scavenging activity: 24.56-33.98 mg TE/g DW). Furthermore, these varieties showed high biological yields (plant height: 27.97-33.93 cm; fresh weight: 8.81-29.17 g/plant) and relatively tender quality.

To identify suitable plant growth regulators in flax production, enhance lodging resistance and increase yield, different levels of paclobutrazol [975 (D1), 1125 (D2), 1275 g/ha (D3)], uniconazole [750 (X1), 900 (X2), 1050 g/ha (X3)] and chlormequat [1200 (A1), 1800 (A2), 2400 mL/ha (A3)] were applied. The changes of plant growth and development, lodging resistance, seed yield and related traits of flax at different levels were studied with clear water as control (CK). The results showed that spraying three plant growth regulators affected the main agronomic traits of flax. Compared with CK, the number of effective branches of D1 treatment decreased, and the number of effective branches and the number of effective capsules per plant of A1 treatment were lower than those of CK. There was no significant difference in root length among the treatments. The root diameter of A2 treatment was significantly higher than that of CK, and the number of seeds per capsule of each treatment was lower than that of CK. The yield per plant of X2 and A2 treatments was significantly higher than that of CK, and the 1000-grain weight of D1 treatment was significantly lower than that of CK. The plant height and center of gravity height of X3 treatment decreased the most, which were 13.63% and 10.34%, respectively. The stem diameter of each treatment was increased compared with CK, and the D2 treatment increased the most, which was 17.5%. There was no significant difference in yield between any treatment and CK. The stem breaking resistance of A2 treatment was significantly higher than that of CK, and there was no significant difference between the other treatments and the control. The lodging index of each treatment was lower than that of CK, except for D1 and D2 treatments, the other treatments were significantly different.The correlation analysis showed that the effective number of capsules per plant, effective branch number, breaking resistance and root diameter were significantly correlated with the yield per plant, and the fresh weight and crown weight were significantly correlated with the lodging index. Through comprehensive analysis, uniconazole was better than chlormequat, chlormequat was better than paclobutrazol, and uniconazole 900 g/ha had better effect in flax production.

To provide a scientific basis for screening the optimal time and intensity of post-sowing compaction for foxtail millet, an indoor pot experiment was conducted to investigate the effects of four compaction times [0 d (A1), 1 d (A2), 2 d (A3), and 3 d (A4) after sowing] and five compaction intensities [0 (T0), 0.25 (T1), 0.50 (T2), 0.75 (T3), and 1.00 kg/cm² (T4)] on the emergence rate of dryland foxtail millet and soil physical properties. The results showed that the emergence rate of foxtail millet was the highest in the A1T3 treatment, reaching 80.77%, an increase of 28.57% compared to the A1T0 treatment. The emergence time was the shortest in the A1T3 treatment, lasting around five days. As the compaction intensity increased, the total soil porosity of all treatments gradually decreased, the soil bulk density gradually increased, and the deviation value of the soil three-phase ratio gradually decreased. Compared to the A1T0 combination, the total soil porosity in the A1T3 combination decreased by 17.67%, the bulk density increased by 62.96%, and the deviation value of the three-phase ratio decreased by 17.48%. In conclusion, immediate post-sowing compaction with an intensity of 0.75 kg/cm² (A1T3) resulted in the best emergence quality of foxtail millet.

Progesterone is a steroid hormone found in plants, which is closely related to plant growth and development and plays a positive role in stress resistance. The growth status of wheat roots directly affects yield and stress resistance. This study investigated the effects of exogenous progesterone on the elongation growth of wheat roots and preliminarily analyzed their regulatory pathways. The results showed that different concentrations of exogenous progesterone exerted varying regulatory effects on wheat root growth: low concentrations (0.001 and 0.01 μmol/L) promoted root elongation, whereas high concentrations (0.1 and 1.0 μmol/L) inhibited growth. Exogenous progesterone treatment significantly affected the glucose content and phosphofructokinase (PFK) activity in the roots of wheat seedlings. With increasing progesterone concentration, the root glucose content first decreased and then increased, while the trend of PFK activity was opposite. Further research found that under 10 μmol/L glucose treatment, the root glucose content decreased and PFK activity increased; under 10 000 μmol/L glucose treatment, the root glucose content increased and PFK activity was inhibited. In addition, the application of 0.1 μmol/L progesterone significantly promoted root glucose accumulation under low-concentration glucose treatment and inhibited the induction effect of glucose on PFK activity. Conversely, the application of 0.001 μmol/L progesterone significantly inhibited root glucose accumulation under high-concentration glucose treatment and alleviated the inhibitory effect of glucose on PFK activity. These findings suggest that exogenous progesterone may affect the glycolysis process by acting on PFK, a key rate-limiting enzyme in the glycolytic pathway, thereby regulating the glucose content in roots and regulating wheat root elongation growth.

To elucidate the effects of nitrogen application rate and N-P-K ratio on the source-sink characteristics of small-seed hybrid rice, a field experiment was conducted using the small-seed hybrid rice variety Zhuoliangyou 0985 as material. The experiment involved four nitrogen application levels [120 (N1), 150 (N2), 180 (N3), and 210 kg/ha (N4)] and three NPK ratios [1.0:0.5:0.8 (F1), 1.0:0.5:1.0 (F2), and 1.0:1.0:1.0 (F3)]. The results showed that leaf area index (LAI), high-efficiency LAI, relative content of chlorophyll (SPAD values), and dry matter accumulation increased with increasing nitrogen application rate. There were no significant differences between N3 and N4 treatments, but both were significantly higher than the N1 treatment. Among different N-P-K ratios, the F3 treatment generally resulted in higher values, though the differences were not significant. Total spikelets and total sink capacity increased with the increase of nitrogen application rate, and the available filled ratio of sink capacity followed the order of N1 > N3 > N2 > N4. Under different N-P-K ratios, the effective filling degree of sink capacity was generally the highest in F2, though the difference was not significant. Effective panicles increased with the increase of nitrogen application rate, while the number of grains per panicle initially increased and then decreased. Both seed-setting rate and 1000-grain weight decreased with the increase of nitrogen application rate, but these differences did not reach a significant level. Yield showed a trend of first increasing and then decreasing with the increase of nitrogen application, with the N3 treatment producing the highest yield. Among the interaction treatments, N3F2 achieved the highest yield, followed by N3F1. Correlation analysis indicated that LAI, high-efficiency LAI, leaf SPAD value, dry matter accumulation, total spikelets, total sink capacity, and effective panicles were extremely significantly and positively correlated with yield. The available filled ratio of sink capacity and seed-setting rate were negatively correlated with yield, while the number of grains per panicle was significantly and positively correlated with yield. No significant correlations were found between 1000-grain weight, grain-leaf ratio, and yield. Under the conditions of this experiment, N3F1 was considered the optimal treatment for Zhuoliangyou 0985. It had a relatively large leaf area, a high number of grains per panicle, a large sink capacity, and a high available filled ratio of sink capacity, with a moderate grain-leaf ratio, which coordinated source-sink relationship and achieved the dual effects of fertilizer saving and yield increase.