Tillage represents an important practice that is used to dynamically regulate soil properties, and affects the grain production process and resource use efficiency of crops. The objectives of this 3-year field study carried out in the Huang-Huai-Hai (HHH) Plain of China were to compare the effects of a new deep vertical rotary tillage (DVRT) with the conventional shallow rotary tillage (CT) on soil properties, winter wheat (Triticum aestivum L.) grain yield and water and nitrogen use efficiency at different productivity levels, and to identify a comprehensive management that optimizes both grain yield and resource use efficiency in the HHH Plain. A split-plot design was adopted in field experiments in the winter wheat growing seasons of 2016–2017 (S1), 2017–2018 (S2) and 2018–2019 (S3), with DVRT (conducted once in June 2016) and CT performed in the main plots. Subplots were treated with one of four targeted productivity level treatments (SH, the super high productivity level; HH, the high productivity and high efficiency productivity level; FP, the farmer productivity level; ISP, the inherent soil productivity level). The results showed that the soil bulk density was reduced and the soil water content at the anthesis stage was increased in all three years, which were due to the significant effects of DVRT. Compared with CT, grain yields, partial factor productivity of nitrogen (PFP_N), and water use efficiency (WUE) under DVRT were increased by 22.0, 14.5 and 19.0%. Path analysis and direct correlation decomposition uncovered that grain yield variation of winter wheat was mostly contributed by the spike numbers per area under different tillage modes. General line model analysis revealed that tillage mode played a significant role on grain yield, PFP_N and WUE not only as a single factor, but also along with other factors (year and productivity level) in interaction manners. In addition, PFP_N and WUE were the highest in HH under DVRT in all three growth seasons. These results provided a theoretical basis and technical support for coordinating the high yield with high resource use efficiency of winter wheat in the resource-restricted region in the HHH Plain of China.

Companion cropping can influence cucumber productivity by altering soil chemical characteristics and microbial communities. However, how these alterations affect the growth of cucumber is still unknown. In this study, seven different plant species were selected as companion plants for testing their effects on cucumber productivity. The effects of different companion plants on changes in soil chemical properties such as electrical conductivity (EC) and contents of essential nutrients as well as the structure and abundance of the soil Pseudomonas community were evaluated. The results showed a higher cucumber yield in the wheat/cucumber companion system than that in the cucumber monocultured and other companion cropping systems. The lowest phosphorus (P) and potassium (K) contents in the soil were found in the cucumber monocultured system, and the highest NO₃⁺-N and NH₄⁺-N contents were observed in the rye/cucumber companion system. PCR-denaturing gradient gel electrophoresis (DGGE) and real-time PCR analysis showed that the trifolium/cucumber companion system increased the diversity of the soil Pseudomonas community, while the chrysanthemum/cucumber companion system increased its abundance. Interestingly, plant-soil feedback trials revealed that inoculating the soil of the wheat/cucumber companion system increased the growth of cucumber seedlings. In conclusion, the effects of different companion plants on cucumber productivity, soil chemical characteristics and the soil Pseudomonas community were different, and wheat was a more suitable companion plant for increasing cucumber productivity. In addition, the altered microbial community caused by companion cropping with wheat contributed to increased cucumber productivity.

Chalcone synthases (CHS, EC 2.3.1.74) are key enzymes that catalyze the first committed step in flavonoid biosynthesis. In this study, we isolated a chalcone synthase, named NtCHS6, from Nicotiana tabacum.  This synthase shared high homology with the NSCHSL (Y14507) gene and contained most of the conserved active sites that are in CHS proteins.  The phylogenetic analysis suggested that NtCHS6 protein shared a large genetic distance with other Solanaceae CHS proteins and was the most closely-related to an uncharacterized CHS from Solanum lycopersicum.  The expression analysis indicated
that NtCHS6 was abundantly expressed in leaves, especially in mature leaves.  By scrutinizing its upstream promoter sequences, multiple cis-regulatory elements involved in light and drought responsive were detected.  Furthermore, NtCHS6 expression decreased significantly under dark treatment and increased significantly under drought stress.  Our results suggested that NtCHS6 expression exhibited both light responsiveness and drought responsiveness, and might play important roles in ultraviolet protection and drought tolerance.

Complicated changes are happening during the aging process of flue-cured tobacco (FCT) and understanding of thechanging components is of great significance in improving the quality, shortening aging time, and enhancing productionand economic efficiency in tobacco industry. The aging samples of FCT from four main producing areas of China, i.e.,Yunnan, Sichuan, Hubei, and Dongbei, were used to study the changing rule of the components such as alkali, acid, andcarbohydrate as well as the aroma and their relationship with sensory quality; and based on the correlation among thecomponents and the sensory quality index, multivariable models were established to predict the aging quality. The resultsshowed that the sensory quality of FCT increased steadily during the aging time, and at the same time, the acidiccomponents (total organic acids, volatile acids) increased gradually, while the alkaline substances (nicotine, volatilealkali), carbohydrate (total sugars, reducing sugar) and pH values showed a downward trend. Correlation analysis foundthat the sensory quality and pH values were negatively correlated (P<0.05), while the sensory quality with total organicacids and aroma were positively correlated. The optimal model for predicting the quality of FCT was y=56.75-0.63x12+50.09x2-13.27x22, (y: sensory quality; x1: pH; x2: total organic acids). The average predicating error was 1.04% with maximumpredicating error of 2.89% and the accuracy rate of above 97%.

Regrowth traits of alfalfa (Medicago sativa L.) in spring are closely related to its fall dormancy before winter. In order todetermine the relationship between fall dormancy (FD) grade and hormone variation pattern and provide academic referencesfor the variety improvement and production of alfalfa, the variations of gibberellins (GA3), indole-3-acetic acid (IAA), andabscisic acid (ABA) in alfalfa roots during regrowth period in spring were examined by high performance liquidchromatography (HPLC). The study involved seven alfalfa cultivars that belonged to four fall dormant grades, i.e., 2, 4, 6,and 8. The results showed that the differences in spring regrowth among the alfalfa cultivars were partially associatedwith their root hormone levels. The alfalfa cultivars that belonged to the same dormancy grades presented similarvariation trends in endogenous hormone content in their roots during the spring regrowth stage. At the early regrowthstage, cultivars with a higher dormant grade had a higher GA3 concent and a lower ABA content in their roots than thecultivars with a lower dormant grade; and IAA content in roots of non- and semi-fall dormancy cultivars was higher thanthat of fall dormancy cultivars. During the whole period of spring regrowth, the root ABA content of fall dormancy alfalfacultivar is significantly higher than those of semi- and non-fall dormancy cultivars. GA3 contents in the roots of allcultivars under study showed a double-peak dynamic curve; root IAA contents of the studied cultivars presented adownward trend. But the trend did not significantly differed among the different fall dormant cultivars. The higher GA3content and lower ABA content in root of non-fall dormancy alfalfa lead to its earlier regrowth. Regrowth time and rate ofalfalfa can be regulated by exogenous GA3 or ABA at the early regrowth stage to meet producing requirement.