Animal wastes as fertilizers enhance growth of young walnut trees under soil drought conditions.

BACKGROUND: Using nutrient-rich animal wastes as organic fertilizers in agricultural practices is a sustainable method for soil amendment and avoiding environmental pollution. In order to evaluate their practical effect, we applied different proportions of animal waste as fertilizers to wet or dry soils that were either planted or not planted with young walnut trees. RESULTS: The results showed that animal waste could increase soil C accumulation and carbon to nitrogen (C/N) ratio and reduce soil organic nitrogen and total nitrogen contents as well as the nitrogen to phosphorus (N/P) ratio in the planted group soil. This framework of soil C and N composition (a high C/N ratio) resulted in high N and Mg contents as well as high Cu and Zn contents in the leaves of the young trees as well as a high dry matter weight/leaf N ratio, causing increased leaf photosynthesis, reduced transpiration and relatively high water use efficiency under soil drought conditions. Also, animal wastes as fertilizers caused the branching of walnut to switch from elongation growth to thickening growth under soil drought conditions. CONCLUSIONS: Principal component analysis and redundancy analysis demonstrated the mechanism by which the soil C/N ratio mediates the flux of available nutrients from the soil to the plant and thereby regulates plant dry matter accumulation and branching architecture under soil drought conditions. The results of this study provide new insights into the improvement of hilly soils using animal waste. © 2020 Society of Chemical Industry.

MiR399d and epigenetic modification comodulate anthocyanin accumulation in Malus leaves suffering from phosphorus deficiency.

Inorganic phosphorus (Pi) deficiency induces anthocyanin accumulation in the leaves of some plant species; however, the molecular mechanisms underlying this phenomenon have not been well characterized. Here, we showed that microRNA399d (miR399d), high-affinity Pi transporter McPHT1;4, and McMYB10 are strongly induced in Malus leaves suffering from Pi deficiency. By culturing explants of transiently transformed plants in MS medium under conditions of Pi sufficiency and Pi deficiency, miR399d and McPHT1;4 were shown to play essential roles in the response to Pi deficiency and to play positive roles in the regulation of anthocyanin biosynthesis. Silencing of McHDA6 expression and treatment with the inhibitor trichostatin A suggested that the low expression of McHDA6 simultaneously reduced the transcription of McMET1 and decreased the methylation level of the McMYB10 promoter; however, the expression of McMYB10 and anthocyanin content were increased. Bimolecular fluorescence complementation and yeast two-hybrid assays revealed that McHDA6 binds directly to McMET1 through its BAH2 and DNMT1-RFD domains. Based on the results of our study, we propose a mechanism for the molecular regulation of anthocyanin biosynthesis, namely, the miR399d and epigenetic modification comodulation model, to explain the phenomenon in which leaves turn red under conditions of Pi deficiency.

An Apple Fruit Fermentation (AFF) Treatment Improves the Composition of the Rhizosphere Microbial Community and Growth of Strawberry (Fragaria × ananassa Duch 'Benihoppe') Seedlings.

Plant growth can be promoted by the application of apple fruit fermentation (AFF), despite unclear of the underlying mechanisms, the effects involved in AFF on rhizosphere microorganisms have been hypothesized. We investigated the consequences of applying AFF alone or in combination with Bacillus licheniformis to strawberry tissue culture seedlings in vitro, the analyses of Denaturing Gradient Gel Electrophoresis (DGGE) and 16S rDNA were performed to determine AFF effects on rhizosphere. Moreover, the growth index and antioxidant enzyme activities were determined 30 days after treatments. We identified five dominant bacteria in AFF: Coprinus atramentarius, Bacillus megaterium, Bacillus licheniformis, Weissella and B. subtilis. The greatest number of bacterial species were observed in the rhizosphere of control matrix (water treated), and the lowest diversity appeared in the rhizosphere soil treated with 108 cfu/mL B. licheniformis alone. Combining AFF plus B. licheniformis in one treatment resulted in the largest leaf area, plant height, root length, plant weight, and the markedly higher activities of antioxidant enzymes. We conclude that a combination of AFF plus B. licheniformis treatment to matrix can increase antioxidant enzymes activities in strawberry seedlings, optimize the status of rhizosphere microbial, and promote plant growth.

Dihydrochalcone Compounds Isolated from Crabapple Leaves Showed Anticancer Effects on Human Cancer Cell Lines.

Seven dihydrochalcone compounds were isolated from the leaves of Malus crabapples, cv. "Radiant", and their chemical structures were elucidated by UV, IR, ESI-MS, ¹H-NMR and (13)C-NMR analyses. These compounds, which include trilobatin (A1), phloretin (A2), 3-hydroxyphloretin (A3), phloretin rutinoside (A4), phlorizin (A5), 6''-O-coumaroyl-4'-O-glucopyranosylphloretin (A6), and 3'''-methoxy-6''-O-feruloy-4'-O-glucopyranosyl-phloretin (A7), all belong to the phloretin class and its derivatives. Compounds A6 and A7 are two new rare dihydrochalcone compounds. The results of a MTT cancer cell growth inhibition assay demonstrated that phloretin and these derivatives showed significant positive anticancer activities against several human cancer cell lines, including the A549 human lung cancer cell line, Bel 7402 liver cancer cell line, HepG2 human ileocecal cancer cell line, and HT-29 human colon cancer cell line. A7 had significant effects on all cancer cell lines, suggesting potential applications for phloretin and its derivatives. Adding a methoxyl group to phloretin dramatically increases phloretin's anticancer activity.