Aluminum and nutrient interplay across an age-chronosequence of tea plantations within a hilly red soil farm of subtropical China

Aluminum (Al) and nutrients are key factors to influence tea (Camellia sinensis L.) productivity and quality, while how they interplay in tea plantations under the pressure of global change and increasing fertilization is little studied. In this study, we selected the tea plantations along an age-chronosequence to study Al fractions using a sequential extraction procedure, and nutrient concentrations in topsoil and subsoil and various plant organs. Our results indicated that Al levels and nutrient concentrations in soils and plants generally increased with planting year (P < 0.05), and soil Al bioavailability was positively correlated with Al concentrations in most plant organs. Significant negative relations among pH and most extractable Al fractions in both soil layers suggested that decreased pH would directly alter soil-plant Al cycling due to exogenous nitrogen (N) fertilizer and atmospheric acid deposition. Topsoil total phosphorus (P) was positively correlated with most Al fractions, and root P was positively correlated with root Al concentration, both of which indicate that P and Al were synchronously absorbed by roots in acid tea soils. In addition, topsoil organic carbon was positively correlated with both active and inert Al fractions, indicating that above-ground organic litters would be the main source of elevated Al levels in older tea plantations. Clearly, Al enrichment in tea leaves with increasing planting year needs to be considered under management practices with heavy N and P fertilizers and increasing atmospheric acid deposition in subtropical China.     

Effects of Residual Mulch Film on the Growth and Fruit Quality of Tomato (<Emphasis Type="Italic">Lycopersicon esculentum</Emphasis> Mill.)

The quantities of residual mulch film in the soil will further increase with the wide application of agricultural plastic mulch film, and the pollution of residual mulch film, which is a continuous pollutant and the one that is difficult to degrade, is a major limiting factor for the sustainable development of agriculture in China. Residual mulch film in the soil inevitably affects soil hydrodynamic parameters, destroys the homogeneity of the soil texture, seriously impedes the movement of soil water and solutes, and thus greatly influences crop growth and fruit quality. To unravel the effects of residual mulch film on tomato growth and fruit quality, pot experiments in the greenhouse were carried out in 2015 and 2016 in Northwest China. Six levels of residual mulch film were applied: 0 kg ha^?1 (CK), 80 kg ha^?1 (T1), 160 kg ha^?1 (T2), 320 kg ha^?1 (T3), 640 kg ha^?1 (T4), and 1280 kg ha^?1 (T5). Plant height, stem diameter, dry biomass, yield, root length, root surface area, fruit shape index (FSI), soluble sugar content (SSC), organic acid (OA), vitamin C (VC), lycopene, and nitrate content (NC) were measured. Plant height, stem diameter, dry biomass, and yield of tomato had a downward trend as the residual mulch film amount increased. Root length and root surface area were significantly decreased with an increasing amount of residual mulch film, but root volume and root diameter showed an inconspicuous decrease. When the amount of residual mulch film was more than 80 kg ha^?1, growth indexes, dry biomass, and yield of tomato showed a sharp decline. FSI, OA, and lycopene decreased as the residual mulch film amount increased, whereas SSC, VC, and NC showed an increase trend. With the increase in residual mulch film amount, the F and membership function values (X _μ ) all showed a declining trend in comparison to the CK. Therefore, residual mulch film can aggravate the negative effects on the comprehensive fruit quality of tomato.     

A swimming mammaliaform from the Middle Jurassic and ecomorphological diversification of early mammals

A docodontan mammaliaform from the Middle Jurassic of China possesses swimming and burrowing skeletal adaptations and some dental features for aquatic feeding. It is the most primitive taxon in the mammalian lineage known to have fur and has a broad, flattened, partly scaly tail analogous to that of modern beavers. We infer that docodontans were semiaquatic, convergent to the modern platypus and many Cenozoic placentals. This fossil demonstrates that some mammaliaforms, or proximal relatives to modern mammals, developed diverse locomotory and feeding adaptations and were ecomorphologically different from the majority of generalized small terrestrial Mesozoic mammalian insectivores.     

Anaerobic Dechlorination of Tetrachlorobisphenol A in River Sediment and Associated Changes in Bacterial Communities

Tetrachlorobisphenol A (TCBPA) is a widely used flame retardant and a potential endocrine disruptor. We estimated the role of the microbial community in degradation of TCBPA in river sediment from the vicinity of an E-waste processing facility. The effects of different anaerobic conditions on degradation efficiency of TCBPA were investigated, and differences in bacterial communities among these conditions were analyzed by 16S ribosomal RNA (rRNA) gene sequencing. The most effective dechlorination of TCBPA occurred under methanogenic conditions followed by electron donor-enhanced conditions and sulfate-reducing conditions with initial sulfate concentrations of 1, 10, and 20 mM. The extent of TCBPA removal under these conditions mentioned above was 65, 44, 43, 23, and 23%, respectively. 16S rRNA gene sequence analysis indicated that five dominant genera in the phylum Chloroflexi and another five species of Bacteroidetes, Chlorobi, and Firmicutes in these five systems were largely involved in TCBPA dechlorination. The initial sample had a total relative abundance of autochtonous potential dechlorinating bacteria of 12%. After 160 days, these values increased to 29–43% under above conditions. Addition of TCBPA decreased bacterial diversity. Efficiency of TCBPA degradation depends on the abundance and metabolism of dechlorinating bacterial guilds. The effectiveness of dechlorinating microbes in degradation of TCBPA was reduced by high sulfate concentrations.     

Improvement of texture properties and flavor of frozen dough by carrot (Daucus carota) antifreeze protein supplementation

The effects of concentrated carrot protein (CCP) containing 15.4% (w/w) carrot (Daucus carota) antifreeze protein on texture properties of frozen dough and volatile compounds of crumb were studied. CCP supplementation lowered the freezable water content of the dough, resulting in some beneficial effects including holding loaf volume steadily and making the dough softer and steadier during frozen storage. Furthermore, SPME-GC-MS analysis showed CCP supplementation did not give any negative influences on volatile compounds of crumb and gave a pleasant aroma felt like Michelia alba DC from trans-caryophyllene simultaneously. Combining our previous results that CCP supplementation improves the fermentation capacity of the frozen dough, CCP could be used as a beneficial additive for frozen dough processing.     

Molecular cytogenetic identification of newly synthetic <Emphasis Type="Italic">Triticum kiharae</Emphasis> with high resistance to stripe rust

Six new amphiploids, Triticum kiharae Dorof. et Migusch. (2n?=?6x?=?42, A^tA^tGGDD), are described in this study. They were developed by the chromosome doubling of F₁ hybrid crosses between Triticum timopheevii Zhuk. (A^tA^tGG) with high resistance to stripe rust and Aegilops tauschii Cosson (DD) by colchicine treatment. These amphiploids showed a high level of fertility of 68–80% and exhibited relatively normal chromosome pairing in meiotic metaphase I. Individual chromosomes of T. kiharae could be identified by multicolor fluorescence in situ hybridization using the combination of oligonucleotides probes Oligo-pSc119.2-1, Oligo-pTa535-1, and Oligo-pTa71-2. T. kiharae exhibited high resistance to predominant stripe rust races CYR34, CYR31, CYR32, CYR33, and SY11-4 both during the seedling and adult stages. However, high molecular weight glutenin subunits from Ae. tauschii parents were only partially expressed in the T. kiharae background. These T. kiharae lines provide novel materials to widen the genetic diversity of the common wheat gene pool.     

Feeding deterrents from Dictamnus dasycarpus Turcz against two stored-product insects

The screening for insecticidal principles from several Chinese medicinal herbs showed that the root bark of Dictamnus dasycarpus possessed significant feeding deterrence against two stored-product insects (Tribolium castaneum and Sitophilus zeamais). From the methanol extract, two feeding deterrents were isolated by bioassay-guided fractionation. The compounds were identified as fraxinellone and dictamnine from their spectroscopic data. Fraxinellone was demonstrated to possess feeding deterrent activity against adults and larvae of T. castaneum as well as S. zeamais adults with EC50 values of 36.4, 29.1, and 71.2 ppm, respectively. Dictamnine was shown to have feeding deterrent activity against adults and larvae of T. castaneum as well as S. zeamais adults with EC50 values of 57.6, 47.9, and 91.7 ppm, respectively.     

Structure characterization and antioxidant activity of a novel polysaccharide isolated from pulp tissues of Litchi chinensis

A novel polysaccharide (LCP50S-2) with antioxidant activity was isolated from Litchi chinensis Sonn. The structure of LCP50S-2 was elucidated on the basis of physicochemical and instrumental analyses, and its average molecular weight was determined by gel permeation chromatography to be 2.19 × 10(2) kDa. The backbone of LCP50S-2 was composed of (1→3)-linked β-L-rhamnopyranosyl residues, (1→4)-linked α-D-xylopyranosyl residues, (1→4)-linked β-D-glucopyranosyl residues, and (1→4)-linked α-D-glucopyranosyl residues which branched at O-6. The two branches consisted of α-L-arabinopyranosyl residues and (1→6)-linked β-D-galactopyranosyl residues terminated with α-L-arabinopyranosyl residues, respectively. In the in vitro antioxidant assay, LCP50S-2 was found to possess DPPH radical-scavenging activity and hydroxyl radical-scavenging activity with IC(50) values of 220 and 266 μg/mL, respectively.     

Influences of U Sources and Forms on Its Bioaccumulation in Indian Mustard and Sunflower

Anthropogenic activities, such as ore mining and processing, nuclear power generation, and weapon tests, have generated uranium (U) contamination to soils and waters. The mobility and bioavailability of U are influenced by its sources, speciation, and plant species. Phytoremediation has emerged as an environmentally friendly, cost-effective green technology to remediate radioisotope- and metal-contaminated soils. The main objective of this study was to explore the feasibility using sunflower (Helianthus annuus) and Indian mustard (Brassica juncea) in cleaning up soils with UO₂, UO₃, and UO₂(NO₃)₂. Uranium was found to be bioaccumulated in plant roots more than plant shoots. Uranium uptake by both plant species was significantly higher from the UO₃- and uranyl-contaminated soils than from UO₂-contaminated soils. UO₃- and UO₂(NO₃)₂-contaminated soils showed higher exchangeable, weak acid extractable, and labile U than the UO₂-contaminated soils. After a growing season, three U forms decreased as redistribution/transformation of U resulted in U species with lower extractability. This study indicates the importance of U speciation in soil with regard to the potential use of sunflower and Indian mustard for phytoremediation of U-contaminated soils.