Calcium (Ca²⁺) plays an important role in determining plant growth and development because it maintains cell wall and
membrane integrity. Therefore, understanding the role of Ca2+ in carbon and lipid metabolism could provide insights
into the dynamic changes in cell membranes and cell walls during the rapid elongation of cotton fibers. In the present
study, we found that the lack of Ca²⁺ promoted fiber elongation and rapid ovule expansion, but it also caused tissue
browning in the ovule culture system. RNA-sequencing revealed that Ca²⁺ deficiency induced cells to be highly oxidized,
and the expression of genes related to carbon metabolism and lipid metabolism was activated significantly. All gene
members of nine key enzymes involved in glycolysis were up-regulated, and glucose was significantly reduced in Ca²⁺
deficiency-treated tissues. Ca²⁺ deficiency adjusted the flowing of glycolysis metabolic. However, low K⁺ recovered
the expression levels of glycolysis genes and glucose content caused by Ca2+ deficiency. Electrospray ionizationtandem
mass spectrometry technology was applied to uncover the dynamic profile of lipidome under Ca²⁺ and K⁺
interacted conditions. Ca²⁺ deficiency led to the decrease of fatty acid (FA), diacylglycerol (DAG), glycolipid and the
significant increase of triacylglycerol (TAG), phospholipid phosphatidylethanolamine (PE), phosphatidylglycerol (PG),
and PC (phosphatidylcholine). Low K⁺ restored the contents of FA, phospholipids, and glycolipids, effectively relieved
the symptoms caused by Ca²⁺ deficiency, and recovered the development of fiber cells. This study revealed dynamic
changes in transcript and metabolic levels and uncovered the signaling interaction of Ca²⁺ deficiency and low K⁺ in
glycolysis and lipid metabolism during fiber development.

To ascertain the possibility of cultivating maize using biological nitrogen fixation (BNF) by leguminous green manure crops in maize/leguminous green manure intercropping systems, BNF and nitrogen (N) transfer were studied in Xining and Wuwei, two typical northwestern Chinese cities.  The experimental treatments included monocultured maize, monocultured green manures (hairy vetch and common vetch), and their intercropping systems.  The proportions of N derived from the atmosphere (%N_dfa) in intercropping systems were not significantly different from that in monocultured green manure systems at either experimental site, except for that in hairy vetch (HV) in Xining.  The amount of N derived from the atmosphere (N_dfa) of common vetch (CV) significantly decreased from 1.16 and 1.10 g/pot in monoculture to 0.77 and 0.55 g/pot when intercropped with maize, in Xining and Wuwei, respectively, and the N_dfa of HV when intercropped significantly decreased from 1.02 to 0.48 g/pot in Xining.  In the intercropping systems in Xining and Wuwei, the amounts of N transferred (N_transfer) from CV to maize were 21.54 and 26.81 mg/pot, accounting for 32.9 and 5.9% respectively of the N accumulation in maize, and the values of N_transfer from HV to maize were 39.61 and 46.22 mg/pot, accounting for 37.0 and 23.3%, respectively, of the N accumulation in maize.  Path analysis showed that soil nutrient and green manure biomass were mainly related to N_dfa, and that ^δ15N had a primary relationship with N_transfer.  We found that 5.9–37.0% of N accumulation in maize was transferred from green manures, and that the N transfer ability to maize of HV was higher than that of CV.  In conclusion, intercropping with leguminous green manures provided a feasible way for maize to effectively utilize biologically fixed N.

Mechanisms controlling phosphorus (P) availability and the roles of microorganisms in the efficient utilization of soil P in the wheat–maize double cropping system are poorly understood.  In the present study, we conducted a pot experiment for four consecutive wheat–maize seasons (2016–2018) using calcareous soils with high (30.36 mg kg^–1) and low (9.78 mg kg^–1) initial Olsen-P content to evaluate the effects of conventional P fertilizer application to both wheat and maize (Pwm) along with a reduced P fertilizer application only to wheat (Pw).  The microbial community structure along with soil P availability parameters and crop yield were determined.  The results showed that the Pw treatment reduces the annual P input by 33.3% without affecting the total yield for at least two consecutive years as compared with the Pwm treatment in the high Olsen-P soil.  Soil water-soluble P concentrations in the Pw treatment were similar to those in the Pwm treatment at the 12-leaf collar stage when maize requires the most P.  Furthermore, the soil P content significantly affected soil microbial communities, especially fungal communities.  Meanwhile, the relative abundances of Proteobacteria and alkaline phosphatase (ALP) activity of Pw were significantly higher (by 11.4 and 13.3%) than those of Pwm in soil with high Olsen-P.  The microfloral contribution to yield was greater than that of soil P content in soil with high Olsen-P.  Relative abundances of Bacillus and Rhizobium were enriched in the Pw treatment compared with the Pwm treatment.  Bacillus showed a significant positive correlation with acid phosphatase (ACP) activity, and Rhizobium displayed significant positive correlations with ACP and ALP in soil with high Olsen-P, which may enhance P availability.  Our findings suggested that the application of P fertilization only to wheat is practical in high P soils to ensure optimal production in the wheat and maize double cropping system and that the soil P availability and microbial community may collaborate to maintain optimal yield in a wheat–maize double cropping system.

Wheat grain yield is generally sink-limited during grain filling.  The grain-filling rate (GFR) plays a vital role but is poorly studied due to the difficulty of phenotype surveys.  This study explored the grain-filling traits in a recombinant inbred population and wheat collection using two highly saturated genetic maps for linkage analysis and genome-wide association study (GWAS).  Seventeen stable additive quantitative trait loci (QTLs) were identified on chromosomes 1B, 4B, and 5A.  The linkage interval between IWB19555 and IWB56078 showed pleiotropic effects on GFR₁, GFR_max, kernel length (KL), kernel width (KW), kernel thickness (KT), and thousand kernel weight (TKW), with the phenotypic variation explained (PVE) ranging from 13.38% (KW) to 33.69% (TKW).  198 significant marker-trait associations (MTAs) were distributed across most chromosomes except for 3D and 4D.  The major associated sites for GFR included IWB44469 (11.27%), IWB8156 (12.56%) and IWB24812 (14.46%).  Linkage analysis suggested that IWB35850, identified through GWAS, was located in approximately the same region as QGFRmax2B.3-11, where two high-confidence candidate genes were present.  Two important grain weight (GW)-related QTLs colocalized with grain-filling QTLs.  The findings contribute to understanding the genetic architecture of the GFR and provide a basic approach to predict candidate genes for grain yield trait QTLs.

In vitro gynogenesis is an important tool used in haploid or homozygous double-haploid plant breeding.  However, because of low repeatability, embryoid induction rate and quality, the molecular mechanisms remain poorly understood.  Heat shock treatment can promote the transformation of the gametophytic pathway into the sporophyte pathway, which induces the occurrence of haploid.  In this study, unfertilized ovaries were heat shocked for 0 h (A0) before flowering and for 0 h (A1), 4 h (A3), 8 h (A5), 12 h (A7), and 24 h (A8), respectively, at 37°C at the first day of the flowering stage.  The ovule enlargement rate was increased from 0% at 25°C to 96.8% at 37°C (24 h treatment).  Thus, we aimed to investigate the gene expression patterns in unfertilized ovules of watermelon after different periods of heat shock by using RNA-Seq technology.  The results showed that compared with A3, A5, A7, and A8, the biosynthesis of amino acid, glycine, serine and threonine metabolic pathways in A1 has changed significantly.  This indicated that heat shock treatment affected the synthesis and transformation of amino acids during ovule expansion.  The transcriptome data suggested gene expressions of ovule growth were significantly changed by heat-specific influences.  The results provide new information on the complex relationship between in vitro gynogenesis and temperature.  This provides a basis for further study of the mechanism of heat shock affecting the expansion of watermelon ovule. 

Intercropping is one of the most vital practice to improve land utilization rate in China that has limited arable land resource. However, the traditional intercropping systems have many disadvantages including illogical field lay-out of crops, low economic value, and labor deficiency, which cannot balance the crop production and agricultural sustainability. In view of this, we developed a novel soybean strip intercropping model using maize as the partner, the regular maize-soybean strip intercropping mainly popularized in northern China and maize-soybean relay-strip intercropping principally extended in southwestern China. Compared to the traditional maize-soybean intercropping systems, the main innovation of field lay-out style in our present intercropping systems is that the distance of two adjacent maize rows are shrunk as a narrow strip, and a strip called wide strip between two adjacent narrow strips is expanded reserving for the growth of two or three rows of soybean plants.  The distance between outer rows of maize and soybean strips are expanded enough for light use efficiency improvement and tractors working in the soybean strips.  Importantly, optimal cultivar screening and increase of plant density achieved a high yield of both the two crops in the intercropping systems and increased land equivalent ratio as high as 2.2.  Annually alternative rotation of the adjacent maize- and soybean-strips increased the grain yield of next seasonal maize, improved the absorption of nitrogen, phosphorus, and potasium of maize, while prevented the continuous cropping obstacles.  Extra soybean production was obtained without affecting maize yield in our strip intercropping systems, which balanced the high crop production and agricultural sustainability.

This experiment was conducted to evaluate the effects of Bupleurum extract (BE) on blood metabolites, antioxidant status, and immune function in dairy cows under heat stress.  Forty lactating Holstein cows were randomly assigned to 1 of 4 treatments.  The treatments consisted of 0, 0.25, 0.5, and 1.0 g of BE kg^–1 dry matter.  Supplementation with BE decreased (P<0.05) blood urea nitrogen (BUN) contents and increased blood total protein (TP) and albumin (ALB) levels compared with control cows, but it had no effects (P>0.05) on blood glucose (GLU), nonesterified fatty acid (NEFA), total triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), and high density lipoprotein cholesterol (HDL-C).  Compared with control cows, cows fed BE had higher (P<0.05) superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activity.  However, supplementation with BE had no effect (P>0.05) on total antioxidant capacity (T-AOC) or malondialdehyde (MDA) levels.  The immunoglobulin (Ig) A and G contents increased (P<0.05) in cows fed 0.25 or 0.5 g of BE kg^–1.  Interleukin (IL)-2 and IL-4 levels were higher (P<0.05) in cows fed 0.5 and 1.0 g of BE kg^–1, and IL-6 was significantly elevated (P<0.05) in cows fed 0.5 g of BE kg^–1.  There were no treatment effects (P>0.05) on the CD4⁺ and CD8⁺ T lymphocyte ratios, CD4⁺/CD8⁺ ratio, or tumor necrosis factor-α (TNF-α) level among the groups.  These findings suggest that BE supplementation may improve protein metabolism, in addition to enhancing antioxidant activity and immune function in heat-stressed dairy cows.  

Two experiments were conducted to investigate the effect of in ovo zinc (Zn) injection on the embryonic development, tissue Zn contents, antioxidation and related gene expressions of fertilized eggs of Arbor Acres broiler breeders.  Experiment 1 was conducted to determine an optimal embryonic age for early in ovo injection.  A total of 720 fertilized eggs with similar weights were randomly allotted to 4 treatments with 6 replicates per treatment and 30 eggs per replicate in a completely randomized design.  The eggs were injected with 0.1 mL sterilized water at 3, 6 and 9 embryonic days of incubation (E3, E6 and E9) or non-injection (the control), respectively.  The results from experiment 1 showed that E3 and E6 injections increased (P<0.05) the embryonic mortalities, and decreased (P<0.05) hatchabilities compared to the non-injected control, but no differences (P>0.05) between E9 injection and the non-injected control were observed in either embryonic mortality or hatchability.  The findings suggest that the E9 is the optimal embryonic age for early in ovo injection.  In experiment 2, a total of 672 fertilized eggs with similar weights were randomly allocated to 7 treatments with 6 replicates per treatment and 16 eggs per replicate in a completely randomized design.  The eggs were injected with 0 (the negative control), 50, 100, 150, 200, or 250 μg Zn/egg as reagent grade ZnSO₄·7H₂O in a 0.1-mL solution, or non-injection (the positive control), respectively at E9–10.  The results from the experiment 2 demonstrated that no differences (P>0.05) among 50 and 100 μg Zn/egg groups and the negative control were observed in the embryonic mortality and hatchability, however, the injection of 200 μg Zn/egg increased (P<0.05) the embryonic mortality, and injections of 150 and 200 μg Zn/egg decreased (P<0.05) hatchabilities compared with the controls.  The embryonic tibia Zn contents at E20 were increased (P<0.05) by injections of 150, 200 and 250 μg Zn/egg.  Zinc injection did not affect (P>0.05) malonaldehyde (MDA) contents, copper- and Zn-containing superoxide dismutase (CuZnSOD) activities and mRNA expression levels in the liver and heart of chick embryos at E15 and E20.  Compared with the negative control, injections of 50, 150 and 200 μg Zn/egg up-regulated (P<0.05) the metallothionein (MT) mRNA expression levels in the embryonic liver at E20.  These results indicated that in ovo Zn injections increased Zn contents in the embryonic tibia and MT mRNA expression levels in the embryonic liver at E20, however, injections of 150–200 µg Zn/egg were harmful to the embryonic development.

The NAC (NAM, ATAF1/2 and CUC2) transcription factor family plays a key role in plant development and responses to abiotic stress.  GmNAC15 (Glyma15g40510.1), a member of the NAC transcription factor family in soybean, was functionally characterized, especially with regard to its role in salt tolerance.  In the present study, qRT-PCR (quantitative reverse transcription PCR) analysis indicated that GmNAC15 was induced by salt, drought, low temperature stress, and ABA treatment in roots and leaves.  GmNAC15 overexpression in soybean (Glycine max) hairy roots enhanced salt tolerance.  Transgenic hairy roots improved the survival of wild leaves; however, overexpression of GmNAC15 in hairy root couldn’t influnce the expression level of GmNAC15 in leaf.  GmNAC15 regulates the expression levels of genes responsive to salt stress.  Altogether, these results provide experimental evidence of the positive effect of GmNAC15 on salt tolerance in soybean and the potential application of genetic manipulation to enhance the salt tolerance of important crops. 

    The tea geometrid Ectropis obliqua is one of the most serious leaf-feeding insect pests in tea (Camellia sinensis) in East Asia. Although several volatile chemicals emitted from tea plants have been reported to be attractive to E. obliqua moths, no synthetic attractants for E. obliqua moths have been developed. By measuring the behavioral responses of the moth to a series of chemicals in the lab, we found that a blend containing a ternary mixture containing (Z)-3-hexenal, (Z)-3-hexenyl hexanoate and benzyl alcohol clearly attracted to E. obliqua moths of both sex and that (Z)-3-hexenyl acetate could enhance the attractiveness of the ternary blend. Moreover, we found that the volatiles emitted from the plant-E. obliqua larva complex have the same attractiveness as: 1) the blend of volatiles containing the ternary mixture and 2) the blend containing (Z)-3-hexenyl acetate plus the ternary mixture to both male and female moths. In a field bioassay, more male moths were observed on traps that were baited with the blend containing (Z)-3-hexenyl acetate plus the ternary mixture than on control traps. Our study raises the tantalizing possibility that synthetic blends could be deployed as attractants for pests in the field.

Crop root system plays an important role in the water cycle of the soil-plant-atmosphere continuum. In this study, combined isotope techniques, root length density and root cell activity analysis were used to investigate the root water uptake mechanisms of winter wheat (Triticum aestivum L.) under different irrigation depths in the North China Plain. Both direct inference approach and multisource linear mixing model were applied to estimate the distribution of water uptake with depth in six growing stages. Results showed that winter wheat under land surface irrigation treatment (T_s) mainly absorbed water from 10–20 cm soil layers in the wintering and green stages (66.9 and 72.0%, respectively); 0–20 cm (57.0%) in the jointing stage; 0–40 (15.3%) and 80–180 cm (58.1%) in the heading stage; 60–80 (13.2%) and 180–220 cm (35.5%) in the filling stage; and 0–40 (46.8%) and 80–100 cm (31.0%) in the ripening stage. Winter wheat under whole soil layers irrigation treatment (Tw) absorbed more water from deep soil layer than T_s in heading, filling and ripening stages. Moreover, root cell activity and root length density of winter wheat under T_w were significantly greater than that of T_s in the three stages. We concluded that distribution of water uptake with depth was affected by the availability of water sources, the root length density and root cell activity. Implementation of the whole soil layers irrigation method can affect root system distribution and thereby increase water use from deeper soil and enhance water use efficiency.

A hydroponic study was conducted to determine the effects of selenium (Se: 0, 3, 6 μmol L−1) on senescence-related oxidative stress in garlic plants grown under two sulfur (S) levels. We evaluated the yields of plants harvested at 160 and 200 days after sowing. Plants grown under a low Se dose (0.3 μmol L−1) at low S level showed higher yields (12.0% increase in fresh weight yield, 13.7% increase in dry weight yield) than the controls, despite a decrease in chlorophyll concentration. Compared with control plants, the Se-treated plants showed lower levels of lipid peroxidation. The Se-treated plants also showed higher activities of glutathione peroxidase and catalase, but lower superoxide dismutase activities. Changes in Fv/Fm values and proline contents were affected more strongly by S than by Se. On the basis of our results, we can conclude that Se plays a key role in the antioxidant systems in garlic seedlings. It delays senescence by alleviating the peroxide stress, but it can be toxic at high levels. A high S level may increase tolerance to high Se concentrations through reducing Se accumulation in plants.

SOM encodes a nucleus-localized CCCH-type zinc finger protein and negatively regulates seed germination in Arabidopsis thaliana. We have previously demonstrated that ectopic expression of SlABI3, an important transcription factor in abscisic acid (ABA) signaling pathway, resulted in alteration of SlSOM expression patterns in both leaf and seed of tomato. In this study, we aimed to elucidate the function of tomato SlSOM in regarding to seed germination and seedling development. Here, we constructed SlSOM over-expression vector pBI121-SOM driven by CaMV 35S promoter, and the recombinant plasmid was incorporated into wild-type tomato by the method of Agrobacterium tumefaciens-mediated transformation. The result showed that over-expression of SlSOM conferred enhanced responses to exogenous ABA application during seed germination and seedling development. In addition, ectopic expression of SlSOM resulted in the alteration of expression level of ABA/GA (gibberellins) metabolic genes, such as SlABA1, SlCYP707A1, SlGA3ox2, and SlGA2ox4, in both leaf and seed. The ABA anabolic gene SlABA1 and the GA catabolic gene SlGA2ox4 were up-regulated while the ABA catabolic gene SlCYP707A1 and the GA anabolic gene SlGA3ox2 were down-regulated. Compared to wild type, the expression level of SlABI5 was increased by about 40–50% in transgenic seeds while adding exogenous ABA treatment. These results support the notion that SlSOM inhibits seed germination by regulating ABA/GA metabolic genes and SlABI5 expression in Solanum lycopersicum.

Improving nitrogen use efficiency (NUE) and decreasing N loss are critical to sustainable agriculture. The objective of this research was to investigate the effect of various fertilization regimes on yield, NUE, N agronomic efficiency (NAE) and N loss in long-term (16- or 24-yr) experiments carried out at three rice-wheat rotation sites (Chongqing, Suining and Wuchang) in subtropical China. Three treatments were examined: sole chemical N, N+phosphorus (NP), and NP+potassium (NPK) fertilizations. Grain yields at three sites were significantly increased by 9.3-81.6% (rice) and 54.5-93.8% (wheat) under NP compared with N alone, 1.7-9.8% (rice) and 0-17.6% (wheat) with NPK compared with NP. Compared to NP, NUE significantly increased for wheat at Chongqing (9.3%) and Wuchang (11.8%), but not at Suining, China. No changes in NUE were observed in rice between NP and NPK at all three sites. The rice-wheat rotation’s NAE was 3.3 kg kg-1 higher under NPK than under NP at Chongqing, while NAE was similar for NP and NPK at Suining and Wuchang. We estimated that an uptake increase of 1.0 kg N ha-1 would increase 40 kg rice and 30 kg wheat ha-1. Nitrogen loss/input ratios were ~60, ~40 or ~30% under N, NP or NPK at three sites, indicating significant decrease of N loss by P or PK additions. We attribute part of the increase in NUE soil N accumulation which significantly increased by 25-55 kg ha-1 yr-1 under NPK at three sites, whereas by 35 kg ha-1 yr-1 under NP at Chongqing only. This paper illustrates that apply P and K to wheat, and reduce K application to rice is an effective nutrient management strategy for both the NUE improvement and N losses reduction in China.

Pulsatilla decoction is a famous traditional Chinese herbal formula for clearing heat and treating dysentery of animals or human. To elucidate its mechanism, many active components have been studied, however, the roles of its polysaccharides still remain unclear. This study aimed to explore effects of polysaccharides from Pulsatilla decoction (PPD) on the microvascular endothelial glycocalyx (eGC). The polysaccharides were extracted from PPD by water extraction and alcohol precipitation method. Mice were administered with PPD for 4 wk, and were then anesthetized with ether inhalation and were fixed by cardiac perfusion with gradient concentration alcian blue solution. The jejunum was sampled and jejunal mucosa was prepared for ultrathin sections by routine method and was analyzed by transmission electron microscope. The results indicated that the eGC was observed as a strong electron-dense smooth linear margin or nonuniform conglomerates coating cell membranes, and PPD significantly increased its thickness from (21.85±1.87) to (28.71±3.61) nm and improved its integrity. This study suggested that PPD may express their biological activities and protect against pathogenic factor damages by influencing the eGC.

The free putrescine (Put) content, the hydrogen peroxide (H2O2) content and the polyamine oxidase (PAO) activity in roots of Malus hupehensis Rehd. var. pinyiensis Jiang (PYTC) were significantly increased, and reached its peak at 1, 2 and 6 h, respectively, under cadmium treatment. The free spermine (Spm) and spermidine (Spd) contents were dramatically decreased, and reached the minimum value at 4-6 h, then remained relatively stable. The change in total free polyamines (PAs) content was consistent with that of free Put. The number of root dead cells was gradually increased after treatment for 24 h, and the typical characteristics of programmed cell death (PCD) were displayed at 48 h. Throughout the Cd treatment process, changes in PAs metabolism appeared to be prior to cell death increase, and the H2O2 content was always maintained at a high level. These results indicated that polyamines could initiate cell death by generating H2O2 in roots of Malus hupehensis Rehd. under CdSO4 stress.

Grain number per-panicle is one of the most important components for rice yield. Spikelets on the primary and secondary branches determine the grain number per-panicle in rice. In this study, we identified a natural mutant, gnp4, lack of lateral spikelet on the secondary branches in the field condition. In addition, the Gnp4 and Lax1-1 double mutant showed dramatically reduced secondary branches and spikelets in panicle at reproductive stage, and tillers at vegetative stage. By map-based cloning approach, and using four F2 segregating populations, the Gnp4 gene was finally mapped to a 10.7-kb region on the long arm of chromosome 4 in rice. In this region, only one gene was predicted, and genomic DNA sequencing of the 10.7-kb region showed no nucleotide differences between the mutant and wild type. Interestingly, we found that the methylation level of several cytosines in the promoter CpG islands region of the predicted gene in gnp4 were different from the wild type. Thus, we propose that the DNA methylation changes at these sites may induce to decrease expression level of Gnp4, consequently, resulting in phenotypic variation.