Effects of biochar on runoff generation, soil and nutrient loss at the surface and underground on the soil-mantled karst slopes.

The effects of biochar (BC) on soil erosion and nutrient output have attracted widespread attention; however, the role of BC in soil and water conservation remains debated. In particular, the effect of BC on underground erosion and nutrient output in soil-mantled karst areas has not been clearly determined. The objective of this study was to investigate the effects of BC on soil and water conservation and nutrient output in surface-underground dual erosion structures in soil-mantled karst areas. Eighteen runoff plots (2 m × 1 m) were established at the Guizhou University research station. Two BC treatments (T1 = 30 t/ha; T2 = 60 t/ha) and a control treatment (CK = 0 t/ha) were used. The BC material was produced from corn straw. The experiment ran from January to December 2021 and a total of 1132.64 mm of rainfall was measured. Runoff and soil and nutrient loss at the surface and underground were collected during natural rainfall. The results showed that 1) compared to CK, the BC application significantly increased surface runoff (SR, P < 0.05) and reduced subsurface runoff (SF, P < 0.05), and underground fissure runoff (UFR) decreased in general but did not reach a significant level (P > 0.05). The total amount of SR collected in each treatment during the test period accounted for 51 %-63 % of the total amount of all collected outlet runoff (SR, SF and UFR); 2) total organic carbon (TOC), total nitrogen (TN) and total phosphorus (TP) were mainly exported through the UFR, and total potassium (TK) was mainly exported through the SR; and 3) compared to CK, the BC reduced TOC, TN and TP output through runoff but had no significant effect on TK output regardless of surface runoff or underground runoff. Thus, BC application reduces nonpoint source (NPS) pollution, and more importantly, it can inhibit TN and TP flow into groundwater through bedrock fissures. Our results provide further evidence for evaluating the soil and water conservation benefits of BC. Therefore, BC in soil-mantled karst agricultural areas can prevent groundwater pollution in karst regions. In general, BC enhances surface erosion and inhibits underground runoff and nutrients loss on soil-mantled karst slopes. This shows that the process through which BC application affects erosion in karst areas is complex, and further research is needed to investigate the long-term effects of BC application in this area.

Artificial Intelligence Assisted Ultrasonic Extraction of Total Flavonoids from Rosa sterilis.

Flavonoids in Rosa sterilis were studied. The flavonoids in Rosa sterilis were extracted by ultrasonic method, and the extraction conditions were modeled and optimized by response the surface methodology and the artificial intelligence method. The results show that the ultrasonic method can effectively extract total flavonoids, and the extraction rate is close to the prediction value of ANN-GA algorithm, which proves the rationality of the model. The order of the effects of the parameters on the experiment was material liquid ratio > extraction power > extraction time > ethanol concentration. In addition, the scavenging effects of flavonoids on DPPH, O2-· and ·OH were also determined, and these indicated that flavonoids have strong antioxidant activities. The kinetics of the extraction process was studied by using the data of the extraction process, and it was found that the extraction process conformed to Fick's first law.

Proteomic analyses provide new insights into the responses of Pinus massoniana seedlings to phosphorus deficiency.

Phosphorus is an essential macronutrient for plant growth and development. Plants can respond defensively to phosphorus deficiency by modifying their morphology and metabolic pathways via the differential expression of low phosphate responsive genes. To better understand the mechanisms by which the Masson pine (Pinus massoniana) adapts to phosphorus deficiency, we conducted comparative proteomic analysis using an elite line exhibiting high tolerance to phosphorus deficiency. The selected seedlings were treated with 0.5 mM KH2PO4 (control), 0.01 mM KH2PO4 (P1), or 0.06 mM KH2PO4 (P2) for 48 days. Total protein samples were separated via 2DE. A total of 98 differentially expressed proteins, which displayed at least 1.7-fold change expression compared to the control levels (p ≤ 0.05), were identified by MALDI-TOF/TOF MS. These phosphate starvation responsive proteins were implicated in photosynthesis, defense, cellular organization, biosynthesis, energy metabolism, secondary metabolism, signal transduction etc. Therefore, these proteins might play important roles in facilitating internal phosphorus homeostasis. Additionally, the obtained data may be useful for the further characterization of gene function and may provide a foundation for a more comprehensive understanding of the adaptations of the Masson pine to phosphorus-deficient conditions.

The temporal transcriptomic response of Pinus massoniana seedlings to phosphorus deficiency.

BACKGROUND: Phosphorus (P) is an essential macronutrient for plant growth and development. Several genes involved in phosphorus deficiency stress have been identified in various plant species. However, a whole genome understanding of the molecular mechanisms involved in plant adaptations to low P remains elusive, and there is particularly little information on the genetic basis of these acclimations in coniferous trees. Masson pine (Pinus massoniana) is grown mainly in the tropical and subtropical regions in China, many of which are severely lacking in inorganic phosphate (Pi). In previous work, we described an elite P. massoniana genotype demonstrating a high tolerance to Pi-deficiency. METHODOLOGY/PRINCIPAL FINDINGS: To further investigate the mechanism of tolerance to low P, RNA-seq was performed to give an idea of extent of expression from the two mixed libraries, and microarray whose probes were designed based on the unigenes obtained from RNA-seq was used to elucidate the global gene expression profiles for the long-term phosphorus starvation. A total of 70,896 unigenes with lengths ranging from 201 to 20,490 bp were assembled from 112,108,862 high quality reads derived from RNA-Seq libraries. We identified 1,396 and 943 transcripts that were differentially regulated (P<0.05) under P1 (0.01 mM P) and P2 (0.06 mM P) Pi-deficiency conditions, respectively. Numerous transcripts were consistently differentially regulated under Pi deficiency stress, many of which were also up- or down-regulated in other species under the corresponding conditions, and are therefore ideal candidates for monitoring the P status of plants. The results also demonstrated the impact of different Pi starvation levels on global gene expression in Masson pine. CONCLUSIONS/SIGNIFICANCE: To our knowledge, this work provides the first insight into the molecular mechanisms involved in acclimation to long-term Pi starvation and different Pi availability levels in coniferous trees.