Organic fertilizer is effective in improving soil quality, and promoting crop growth. Combined organic and inorganic fertilization has been proved as a more favorable way to tobacco yield and quality. However, the mechanisms underlying tobacco yield and quality under combinations of different organic and inorganic fertilizer remain unclear. We conducted a 12-year tobacco (Nicotiana tabacum L.)-maize crop rotation field experiment in Yanhe experimental station, China to examine the yields and qualities of tobacco, soil nutrients, and extracellular enzyme activities associated with carbon, nitrogen, and phosphorus cycles in response to different fertilization treatments. Five fertilization treatments (no fertilization; 75 kg N fertilizer ha-1; 450 kg oil cake ha-1 + 75 kg N fertilizer ha-1; 15,000 kg pig dung ha-1 + 60 kg N fertilizer ha-1; 3,000 kg straw ha-1 + 75 kg N fertilizer ha-1) were applied to tobacco while maize was fertilized with inorganic compound fertilizers. After 12 years of tobacco-maize rotation, the results showed that organic fertilizer additions elevate tobacco yield and quality, and the soil extracellular enzymes activities. Gram-negative bacteria, actinomycetes, and total soil microbial biomass were increased by organic fertilizer additions, both plant-based (oil cake and straw) and animal-based (pig dung) organics. The levels of soil organic matter, total organic carbon, total phosphorus and available phosphorus are higher in pig dung addition treatment than oil cake and straw additions. By variance analysis with respect to fertilization treatments, organic sources differentially affected the activities of diverse soil enzymes. The redundancy analysis gave that yield and quality of tobacco leaves (upper, middle, and lower leaves) positively related to soil extracellular enzyme activities. Based on analysis of yield and quality of tobacco leaves with extracellular enzyme activities and soil nutrients, it is suggested animal-based organic fertilizer, thus pig dung, should be used in combining with chemical fertilizers to improve the quality of tobacco and soil nutrients.
Plants have sophisticated defense systems to fend off insect herbivores. How plants defend against herbivores in dicotyledonous plants, such as Arabidopsis and tobacco, have been relatively well studied, yet little is known about the defense responses in monocotyledons. Here, we review the current understanding of rice (Oryza sativa) and maize (Zea mays) defense against insects. In rice and maize, elicitors derived from insect herbivore oral secretions or oviposition fluids activate phytohormone signaling, and transcriptomic changes mediated mainly by transcription factors lead to accumulation of defense-related secondary metabolites. Direct defenses, such as trypsin protein inhibitors in rice and benzoxazinoids in maize, have anti-digestive or toxic effects on insect herbivores. Herbivory-induced plant volatiles, such as terpenes, are indirect defenses, which attract the natural enemies of herbivores. R gene-mediated defenses against herbivores are also discussed.
Abstract: Extraction and assay conditions for β‐glucosidase from propolis were optimized. Highest enzyme activity was obtained in a citric acid‐disodium hydrogen phosphate buffer at pH 6.0 with 2.5% insoluble polyvinylpyrrolidone at incubation temperature of 57 °C. β‐Glucosidase activities were found in all freshly harvested propolis while β‐glucosidase activities were scarcely present in the randomly bought propolis. Propolis was stored at –20 °C and 4 °C for 3 mo with almost no loss of β‐glucosidase activity, but at room temperature the activity decreased exponentially with the increase of storage time. These results indicated that the activity of β‐glucosidase could be a candidate for propolis‐freshness index. β‐Glucosidase from propolis was capable of hydrolyzing p‐ nitrophenyl‐β‐D‐glucoside and p‐ nitrophenyl‐β‐D‐galactoside, but lacked activity toward p‐ nitrophenyl‐β‐D‐glucuronide, p‐ nitrophenyl‐β‐D‐cellobioside, amygdalin, cellobiose, and gentiobiose. These results were consistent with the hypothesis that flavonoid glucosides were hydrolyzed by β‐glucosidase during propolis collection and processing and provided a possible explanation for why some flavonoid biosides (that is, rutin and isorhamnetin‐3‐O‐rutinoside) exist in propolis. Practical Application: β‐Glucosidase activity was detected and partial characterization of the enzyme was determined in propolis. The enzyme activity decreased exponentially with the increase of storage time at room temperature, which suggested that the activity of β‐glucosidase could be regarded as a freshness index of propolis. The research will be useful for studying the chemical constituents of propolis.
Attractive effects of sex pheromone on three major lepidopteran pest insects,namely Agrotis ypsilon,Heliothis assulta and Spodoptera litura were studied in tobacco fields.Results showed that sex pheromone lures could attract target pest insects,but the effect of attraction on Agrotis ypsilon and Heliothis assulta were not significant.Sex pheromone lure showed a high attractive effect on Spodoptera litura and could be further widely applied.However,different directions led different capture effects,indicating the importance of fixing technique of sex pheromone traps.
Significance Achieving inclusive, green development is crucial to China and the world. Over the past century, great increases in agricultural production have been achieved at the expense of other ecosystem benefits, such as flood control, water purification, climate stabilization, and biodiversity conservation. We report on an application of China’s new “Ecological Development Strategy,” which aims to break these trade-offs and be scaled nationwide. Focusing on Hainan Island, where rubber production has driven loss of natural forest, we identified a two-pronged strategy that would eliminate these trade-offs, simultaneously diversifying and enhancing product provision, rural incomes, and many other ecosystem benefits. This win−win approach has broad applicability in the plantation regions in China, across South and Southeast Asia, and beyond.
Abstract Fatty acid biosynthesis is essential for bacterial survival. Of these promising targets, β ‐ketoacyl‐acyl carrier protein (ACP) synthase III (FabH) is the most attractive target. A series of novel 1,3,4‐oxadiazole‐2(3 H )‐thione derivatives containing 1,4‐benzodioxane skeleton targeting FabH were designed and synthesized. These compounds were determined by 1 H‐NMR, 13 C‐NMR, MS and further confirmed by crystallographic diffraction study for compound 7m and 7n . Most of the compounds exhibited good inhibitory activity against bacteria by computer‐assisted screening, antibacterial activity test and E. coli FabH inhibitory activity test, wherein compounds 7e and 7q exhibited the most significant inhibitory activities. Besides, compound 7q showed the best E. coli FabH inhibitory activity (IC 50 =2.45 μΜ). Computational docking studies also showed that compound 7q interacts with FabH critical residues in the active site.
Microbial flora composition of microbial fuel cells (MFC) is important to the electricity generation. Four bacterium strains Q1, b, c and d which represent all different morphology of culturable bacterium were isolated from a MFC using 200 mg x L(-1) quinoline as the fuel and operating for at least 210 days. Strains Q1, c and d were Pseudomonas sp. based on 16S rDNA sequence analysis, while strain b was Burkholderia sp. Double-chamber MFCs using 200 mg x L(-1) quinoline and 300 mg x L(-1) glucose as the fuel and potassium ferricyanide as the electron acceptor were constructed. Results showed that strain b, c and d were non-electrogenesis. The electrical charges of MFC inoculated electrogenesis strain Q1 with non-electrogenesis strain b, c and d respectively were 3.00, 3.57 and 5.13C, and the columbic efficiency were 3.85%, 4.59% and 6.58%, which were all lower than that inoculated with pure Q1, because of the interspecific competition of electrogenesis and non-electrogenesis bacteria. Combinations of Q1 with the other three strains respectively resulted in 100% of quinoline degradation rates within 24h, which is better than pure cultures, that is, mixed microbial populations perform better in MFC when complex organics are used as the fuel. GC/MS analyses showed that only 2(1H)-quinolinone and phenol existed in the effluent of the MFC, which was inoculated with only Q1 or mixed bacteria.
Abstract Jasmonic acid (JA) plays a critical role in plant defenses against insects and necrotrophic fungi. Wounding or lepidopteran insect feeding rapidly induces a burst of JA in plants, which usually reaches peak values within 1 to 2 h. The induced JA is converted to JA‐Ile and perceived by the COI1‐JAZ co‐receptor, leading to activation of the transcription factors MYC2 and its homologs, which further induce JA‐responsive genes. Although much is known about JA biosynthesis and catabolism enzymes and JA signaling, how JA biosynthesis and catabolism are regulated remain unclear. Here, we show that in Arabidopsis thaliana MYC2 functions additively with MYC3 and MYC4 to regulate wounding‐induced JA accumulation by directly binding to the promoters of genes function in JA biosynthesis and catabolism to promote their transcription. MYC2 also controls the transcription of JAV1 and JAM1 , which are key factors controlling JA biosynthesis and catabolism, respectively. In addition, we also found that MYC2 could bind to the MYC2 promoter and self‐inhibit its own expression. This work illustrates the central role of MYC2/3/4 in controlling wounding‐induced JA accumulation by regulating the transcription of genes involved in JA biosynthesis and catabolism.
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