Rhododendron is a well-known genus consisting of commercially valuable ornamental woody plant species.  Heat stress is a major environmental factor that affects rhododendron growth.  Melatonin was recently reported to alleviate the effects of abiotic stress on plants.  However, the role of melatonin in rhododendron plants is unknown.  In this study, the effect of melatonin on rhododendron plants exposed to heat stress and the potential underlying mechanism were investigated.  Analyses of morphological characteristics and chlorophyll a fluorescence indicated 200 µmol L^–1 was the optimal melatonin concentration for protecting rhododendron plants from heat stress.  To elucidate how melatonin limits the adverse effects of high temperatures, melatonin contents, photosynthetic indices, Rubisco activity, and adenosine triphosphate (ATP) contents were analyzed at 25, 35, and 40°C, respectively.  Compared with the control, exogenous application of melatonin improved the melatonin contents, electron transport rate, photosystem II and I activities, Rubisco activity, and ATP contents under heat stress.  The transcriptome analysis revealed many of the heat-induced differentially expressed genes were associated with the photosynthetic pathway; the expression of most of these genes was down-regulated by heat stress more in the melatonin-free plants than in the melatonin-treated plants.  We identified RhPGR5A, RhATPB, RhLHCB3, and RhRbsA as key genes.  Thus, we speculate that melatonin promotes photosynthetic electron transport, improves Calvin cycle enzyme activities, and increases ATP production.  These changes lead to increased photosynthetic efficiency and CO₂ assimilation under heat stress conditions via the regulated expression of specific genes, including RhRbsA.  Therefore, the application of exogenous melatonin may increase the tolerance of rhododendron to heat stress.

Myo-inositol and its derivatives play important roles in the tolerance of higher plants to abiotic stresses, and myo-inositol-1-phosphate synthase (MIPS) is the rate-limiting enzyme in myo-inositol biosynthesis.  In this study, we found that increased myo-inositol biosynthesis enhanced drought tolerance in MdMIPS1-overexpressing apple lines under short-term progressive drought stress.  The effect of myo-inositol appeared to be mediated by the increased accumulation of osmoprotectants such as glucose, sucrose, and proline, and by the increased activities of antioxidant enzymes that eliminate reactive oxygen species.  Moreover, enhanced water-use efficiency (WUE) was observed in MdMIPS1-overexpressing apple lines under long-term moderate water deficit conditions that mimicked the water availability in the soil of the Loess Plateau.  Enhanced WUE may have been associated with the synergistic regulation of osmotic balance and stomatal aperture mediated by increased myo-inositol biosynthesis.  Taken together, our findings shed light on the positive effects of MdMIPS1-mediated myo-inositol biosynthesis on drought tolerance and WUE in apple.

Dopamine is a catecholamine and an anti-oxidant which functions in responses to stress and it interacts with plant hormones to mediate plant development.  At present, there are few studies on the functions of dopamine in apple.  This study developed a method for dopamine determination which was used to analyze dopamine in Malus germplasm, in order to clarify the tissue distribution, developmental changes, diurnal variations, and stress responses in apple trees.  First, the proposed method was verified.  The linear range of quantification was robust from 0.1 to 20 ng mL^–1.  The instrumental, inter-day precision, and sample repeatability relative standard deviations were 1.024, 5.607, and 7.237%, respectively.  The spiked recovery was greater than 100%, indicating the feasibility of the method and its suitability for the rapid analysis of dopamine in Malus.  Next, the dopamine content was measured in 322 Malus tissues.  The results showed that the dopamine level in Malus was low and the average dopamine content in leaf was higher than in peel and flesh.  The dopamine had a skewed distribution that deviated to the right in cultivars and wild accessions.  Finally, the tissue specificity, developmental changes, diurnal changes, and responses to stress were analyzed.  In cultivar ‘Pinova’ (Malus domestica), the dopamine concentration was the highest in leaf buds and lowest in flesh.  The dopamine contents in leaf and flesh decreased with the growth and development of cultivar ‘Liangxiang’ (Malus domestica).  The dopamine content of apple leaves was higher after either drought or salinity stress as compared to the control.  In this study, a dopamine detection method for apple was established based on HPLC-MS and shown to be a robust approach.  This study provides a framework for future research on elucidating the tissue distribution, developmental changes, diurnal variation, and stress responses of dopamine in apple trees.

Excessive rainfall provides a favorable condition for field mold infection of plants, which triggers field mold (FM) stress.  If FM stress occurs during the late maturation stage of soybean seed, it negatively affects seed yield and quality.  To investigate the responses of soybean seed against FM stress and identify the underlying biochemical pathways involved, a greenhouse was equipped with an artificial rain producing system to allow the induction of mold growth on soybean seed.  The induced quality changes and stress responses were revealed on the levels of both transcriptome and metabolome.  The results showed that soybean seeds produced under FM stress conditions had an abnormal and inferior appearance, and also contained less storage reserves, such as protein and polysaccharide.  Transcriptional analysis demonstrated that genes involved in amino acid metabolism, glycolysis, tricarboxylic acid, β-oxidation of fatty acids, and isoflavone biosynthesis were induced by FM stress.  These results were supported by a multiple metabolic analysis which exhibited increases in the concentrations of a variety of amino acids, sugars, organic acids, and isoflavones, as well as reductions of several fatty acids.  Reprogramming of these metabolic pathways mobilized and consumed stored protein, sugar and fatty acid reserves in the soybean seed in order to meet the energy and substrate demand on the defense system, but led to deterioration of seed quality.  In general, FM stress induced catabolism of storage reserves and diminished the quality of soybean seed in the field.  This study provides a more profound insight into seed deterioration caused by FM stress.

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.

The present study investigates the chemical composition and antioxidant capacity of juice from the Gannan navel orange, which is harvested at one- to two-week intervals during the ripening period.  The total soluble solid (TSS), total polyphenol content (TPC), total flavonoid content (TFC), sucrose and hesperidin contents gradually increase with the ripening of the fruit, followed by slight declines at the late maturity stage.  Contrary to these observations, the contents of titratable acid (TA), vitamin C (Vc), and limonin trend downward throughout the ripening period.  However, the contents of fructose, glucose, and narirutin fluctuate throughout the harvest time.  Three in vitro antioxidant assays consistently indicate that the harvest time exerts no significant influence (P>0.01) on the antioxidant capacity.  Furthermore, principal component analysis (PCA) and Pearson’s correlation test are performed to provide an overview of the complete dataset. This study provides valuable information for evaluating the fruit quality and determining when to harvest the fruit in order to meet the preferences of consumers.  Meanwhile, our observations suggest that the fruits subjected to juice processing should be harvested at the late maturity stage to alleviate the “delayed bitterness” problem without compromising the antioxidant capacity and the flavonoid content in the juice.

Significant progress has been achieved in the use of heterosis in soybean and several soybean hybrids have been released in China. However, broad use of hybrid soybean seed is limited due to low seed setting of female parents.  Breeding cytoplasmic male sterile (CMS) lines with high out-crossing rate is necessary to solve the problem.  The objective of this study was to determine the relationship between out-crossing rate of CMS lines and their nectar secretion.  The daily nectar secretion rhythm, meteorological effect on nectar secretion, and differences in nectar secretion among genotypes and years were investigated in 27 soybean CMS lines (A-lines) with their maintainers (B-lines) and restorers (R-lines).  The correlation between out-crossing rate of CMS lines and nectar production was also evaluated.  Nectar secretion had diurnal variation.  Secretion initiated at about 06:00 for most materials and reached a peak at 07:00–08:30 after flower opened, then the nectar secretion decreased gradually.  A sub-peak appeared at about 13:00, while the nectar could not be detected at 17:00.  Nectar secretion was greatly influenced by the weather conditions.  The amount of nectar secretion increased gradually over time during periods of high temperature and no rainfall for several days.  Rainy weather and low temperatures inhibited nectar secretion.  There were obvious variations of nectar amount among different genotypes tested.  Significant nectar variation within a genotype among years was also observed, and the highest nectar secretion was 3-fold higher than the lowest.  The amount of nectar secretion from R-lines was significantly higher than that of A- and B-lines.  There was no significant difference in nectar secretion between A- and B-lines.  A- and B-lines with higher out-crossing rates secreted more nectar.  The amount of nectar secretion of A- and B-lines were significantly positively correlated with the out-crossing rate of A-lines.

The cultivar Ganoderma lucidum Hunong 5 was obtained using cross-breeding.  Hunong 5 has high commercial value due to its high polysaccharide and triterpene content.  This is the first report of using a DNA pooling method to develop a stable sequence characterized amplified region (SCAR) marker for rapid identification of the G. lucidum Hunong 5 cultivar.  The SCAR marker was developed by first generating and sequencing a distinctive inter simple sequence repeat (ISSR) fragment (882 bp) from G. lucidum Hunong 5 cultivar.  A stable SCAR primer pair GLH5F/GLH5R were obtained to identify the cultivar and the SCAR marker is a DNA fragment of 773 bp.

Ecological engineering involves the use of plants to promote establishment, survival and efficiency of natural enemies in agricultural systems.  Some plant species may be hosts or provide resources to some pest species.  We assessed the risks and benefits of sesame (Sesamum indicum L.), as a nectar source for seven economically important Lepidopteran pest and four parasitoid species in a range of vegetable crop systems.  Our results showed that the mean longevities of arthropod parasitoids Pteromalus puparum (L.), Encarsia sophia (Girault & Dodd) and male Microplitis tuberculifer (Wesmael) were significantly extended when fed on sesame flowers compared to the water control.  Sesame flowers had no effect on adult longevities and fecundities of six out of the seven Lepidoptera pest species tested except Plutella xyllostella (L.) females laid more eggs when fed on sesame flowers.  It is likely that the increased fecundity is due to accessibility to nectar at the bottom of corolla because of their smaller body sizes.  Our findings provide a first step towards better understanding of the risks and benefits of using sesame to implement ecological engineering for the management of vegetable pests.

Crop modelling can facilitate researchers’ ability to understand and interpret experimental results, and to diagnose yield gaps. In this paper, the Decision Support Systems for Agrotechnology Transfer 4.6 (DSSAT) model together with the CENTURT soil model were employed to investigate the effect of low nitrogen (N) input on wheat (Triticum aestivum L.) yield, grain N concentration and soil organic carbon (SOC) in a long-term experiment (19 years) under a wheat-maize (Zea mays L.) rotation at Changping, Beijing, China.  There were two treatments including N0 (no N application) and N150 (150 kg N ha^–1) before wheat and maize planting, with phosphorus (P) and potassium (K) basal fertilizers applied as 75 kg P₂O₅ ha^–1 and 37.5 kg K₂O ha^–1, respectively.  The DSSAT-CENTURY model was able to satisfactorily simulate measured wheat grain yield and grain N concentration at N0, but could not simulate these parameters at N150, or SOC in either N treatment.  Model simulation and field measurement showed that N application (N150) increased wheat yield compared to no N application (N0).  The results indicated that inorganic fertilizer application at the rates used did not maintain crop yield and SOC levels.  It is suggested that if the DSSAT is calibrated carefully, it can be a useful tool for assessing and predicting wheat yield, grain N concentration, and SOC trends under wheat-maize cropping systems.

We carried out a pool culture experiment to determine the optimal water treatment depth in loam and clay soils during the late growth stage of super rice.  Three controlled water depth treatments of 0–5, 0–10 and 0–15 cm below the soil surface were established using alternate wetting and drying irrigation, and the soil water potential (0 to –25 kPa) was measured at 5, 10 and 15 cm.  A 2-cm water layer was used as the control.  We measured soil enzyme activities, root antioxidant enzyme activities, chlorophyll fluorescence parameters, and rice yield.  The results showed that the 0–5-cm water depth treatment significantly increased root antioxidant enzyme activities in loam soil compared with the control, whereas soil enzyme activities, chlorophyll fluorescence parameters and yield did not differ from those of the control.  The 0–10- and 0–15-cm water depth treatments also increased root antioxidant enzyme activities, whereas soil enzyme activities, chlorophyll fluorescence parameters and yield decreased.  In clay soil, the soil enzyme activities, root antioxidant enzyme activities, chlorophyll fluorescence parameters, and yield did not change with the 0–5-cm water treatment, whereas the 0–10- and 0–15-cm water treatments improved these parameters.  Therefore, the appropriate depths for soil water during the late growth period of rice with a 0 to –25 kPa water potential were 5 cm in loam and 15 cm in clay soil.

Genomic selection has been demonstrated as a powerful technology to revolutionize animal breeding.  However, marker density and minor allele frequency can affect the predictive ability of genomic estimated breeding values (GEBVs).  To investigate the impact of marker density and minor allele frequency on predictive ability, we estimated GEBVs by constructing the different subsets of single nucleotide polymorphisms (SNPs) based on varying markers densities and minor allele frequency (MAF) for average daily gain (ADG), live weight (LW) and carcass weight (CW) in 1 059 Chinese Simmental beef cattle.  Two strategies were proposed for SNP selection to construct different marker densities: 1) select evenly-spaced SNPs (Strategy 1), and 2) select SNPs with large effects estimated from BayesB (Strategy 2).  Furthermore, predictive ability was assessed in terms of the correlation between predicted genomic values and corrected phenotypes from 10-fold cross-validation.  Predictive ability for ADG, LW and CW using autosomal SNPs were 0.13±0.002, 0.21±0.003 and 0.25±0.003, respectively.  In our study, the predictive ability increased dramatically as more SNPs were included in analysis until 200K for Strategy 1.  Under Strategy 2, we found the predictive ability slightly increased when marker densities increased from 5K to 20K, which indicated the predictive ability of 20K (3% of 770K) SNPs with large effects was equal to the predictive ability of using all SNPs.  For different MAF bins, we obtained the highest predictive ability for three traits with MAF bin 0.01–0.1.  Our result suggested that designing a low-density chip by selecting low frequency markers with large SNP effects sizes should be helpful for commercial application in Chinese Simmental cattle.

Extreme meteorological disaster effects on grain production is mainly determined by the interaction between danger degree of hazard-induced factors and vulnerability degree of hazard-affected bodies.  This paper treats physical exposure, sensitivity of the response to the impact, and capabilities of disaster prevention and mitigation as a complex system for vulnerability degree of hazard-affected bodies, which included the external shocks and internal stability mechanism.  Hazard-induced factors generate external shocks on grain production systems though exposure and sensitivity of hazard-affected body, and the result can be represented as affected area of grain.  By quantile regression model, this paper depicts the quantitative relationship between hazard-induced factors of extreme meteorological disaster and the affected area in the tail of the distribution.  Moreover, the model of production function have also been utilized to expound and prove the quantitative relationship between the affected area and final grain output under the internal stability mechanism of the agricultural natural resources endowment, the input factors of agricultural production, and the capacity of defending disaster.  The empirical study of this paper finds that impact effects of drought disaster to grain production system presents the basic law of “diminishing marginal loss”, namely, with the constant improvement of the grade of drought, marginal affected area produced by hazard-induced factors will be diminishing.  Scenario simulation of extreme drought impact shows that by every 1% reduction in summer average rainfall, grain production of Jilin Province will fell 0.2549% and cut production of grain 14.69% eventually.  In response to ensure China’s grain security, the construction of the long-term mechanism of agricultural disaster prevention and mitigation, and the innovation of agricultural risk management tools should be also included in the agricultural policy agenda.

  The safety of feeding transgenic cry1Ab/cry1Ac rice (a genetically modified (GM) rice variety) to broilers was examined from an immunological perspective. Hatchling Arbor Acres chickens (240) were assigned to two dietary treatments (diets containing GM or non-GM rice) with 12 replicates per group and 10 birds per replicate. Traits were measured on one randomly selected bird from each replicate at d 21 and 42. The 42-d feeding trial revealed that cry1Ab/cry1Ac rice had no significant effect relative to non-GM rice on body weight and the immune organ indices. No significant pathological lesion in the spleen and bursa of Fabricius was found in the GM rice group. There were no significant differences in serum concentrations of immunoglobulin Y (IgY), IgM, interleukin 4 (IL-4) and IL-6 between the two groups at d 21 or 42, except for IL-6 being higher (P<0.05) in the GM-fed chickens at d 42. There were no differences in the T and B lymphocyte transformation rate and CD4+/CD8+ ratio between the two groups at d 42. Additionally, there was no significant difference between the two diets in expression of relevant genes viz. the major histocompatibility complex class II beta chain (BLB2), interferon beta 1 (IFNβ), tumour necrosis factor alpha-like (TNFα) and toll-like receptor 4 (TLR4) in the spleen and bursa of Fabricius. All the data demonstrated that transgenic cry1Ab/cry1Ac rice had no adverse effect on these aspects of immune function of broilers during 42-d feeding trial. Transgenic rice was therefore indistinguishable from non-GM rice in terms of short-term feeding in chickens.  

Rice panicles are composed of many branches with two types of extreme grains, the superior and the inferior. Traditionally, it has been well accepted that earlier flowers result in superior grains and late flowers generate inferior grains. However, these correlations have never been strictly examined in practice. In order to determine the accurate relationship between superior and inferior grains and the flowering order, we localized all the seeds in a panicle in four distinct rice species and systematically documented the rice flowering order, flower locations and the final grain weight for their relationships. Our results demonstrated that the grain weight is more heavily determined by the position of the seeds than by the flowering order. Despite earlier flowering has a positive correlation with the grain weight in general, grains from flowers blooming on the second day after anthesis generally gained the highest weight. This suggests earlier flowers may not result in superior grains. Therefore, we concluded that superior and inferior grains, commonly determined by grain weight, are not fully correlated with the flowering order in rice. Following the order of the grain weight, the superior grains are generally localized at the middle parts of the primary branches, whereas inferior grains were mainly on the last two secondary branches of the lower half part of the panicle. In addition, the weight of inferior grains were affected by spikelet thinning and spraying with exogenous plant growth regulators, indicating that physiological incompetence might be the major reason for the occurrence of the inferior grains.

In order to establish double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) for detection of duck or goose flavivirus, polyclonal antibody against the flavivirus strain JS804 in geese and monoclonal antibody against the E protein of flavivirus strain JS804 in geese were used as the capture antibody and detection antibody, respectively. The optimal dilution of the capture antibody and detecting antibody capable of detecting the flavivirus strain JS804 in geese were 1:3 200 and 1:160 in the check-board titration, respectively. The reaction time of sample was 1 h, and the optimal working dilution of HRP-labeled goat-anti-mouse IgG was 1:10 000. The positive standard value was 0.247 (OD450 nm). The geese flavivirus could be detected at a minimal concentration of 1.875 μg mL-1. The ELISA had no cross-reaction with Newcastle disease virus (NDV), Avian influenza virus (AIV), Infectious bronchitis virus (IBV), Infectious bursal disease virus (IBDV), Duck hepatitis virus (DHV), and Gosling plague virus (GPV). Twenty clinical samples were detected by the DAS-ELISA and RT-PCR respectively, with the agreement rate of 75%. The results revealed that the DAS-ELISA possessed favorable specificity and higher sensitivity, indicating a suitable method for rapid detection of the duck or goose flavivirus.

Powdery mildew (Blumeria graminis) is one of the most destructive crop diseases infecting winter wheat plants, and has devastated millions of hectares of farmlands in China. The objective of this study is to detect the disease damage of powdery mildew on leaf level by means of the hyperspectral measurements, particularly using the continuous wavelet analysis. In May 2010, the reflectance spectra and the biochemical properties were measured for 114 leaf samples with various disease severity degrees. A hyperspectral imaging system was also employed for obtaining detailed hyperspectral information of the normal and the pustule areas within one diseased leaf. Based on these spectra data, a continuous wavelet analysis (CWA) was carried out in conjunction with a correlation analysis, which generated a so-called correlation scalogram that summarizes the correlations between disease severity and the wavelet power at different wavelengths and decomposition scales. By using a thresholding approach, seven wavelet features were isolated for developing models in determining disease severity. In addition, 22 conventional spectral features (SFs) were also tested and compared with wavelet features for their efficiency in estimating disease severity. The multivariate linear regression (MLR) analysis and the partial least square regression (PLSR) analysis were adopted as training methods in model development. The spectral characteristics of the powdery mildew on leaf level were found to be closely related with the spectral characteristics of the pustule area and the content of chlorophyll. The wavelet features performed better than the conventional SFs in capturing this spectral change. Moreover, the regression model composed by seven wavelet features outperformed (R2=0.77, relative root mean square error RRMSE=0.28) the model composed by 14 optimal conventional SFs (R2=0.69, RRMSE=0.32) in estimating the disease severity. The PLSR method yielded a higher accuracy than the MLR method. A combination of CWA and PLSR was found to be promising in providing relatively accurate estimates of disease severity of powdery mildew on leaf level.

The developmental competence of porcine parthenotes cultured in porcine zygote medium-3 (PZM-3) and North Carolina State University-23 (NCSU-23) media was investigated. After in vitro maturation oocytes were electro-activated, and the subsequent developmental competence, rates of apoptotic, fragmented and arrested embryos from the two media were evaluated. Also, the ratio of mRNA expression of Bcl-2 and Bax gene was determined. Results demonstrated that cleavage, blastocyst, hatched blastocyst rates, and blastocyst cell numbers were significantly higher in PZM-3 than in NCSU-23. The rate of fragmented embryos in PZM-3 was lower than in NCSU-23 on d 1 and 3 (P<0.05) while the percentage of arrested embryo was lower in PZM-3 than in NCSU-23 on d 4 and 5 (P<0.05). TUNEL positive signals were higher in NCSU-23 than in PZM-3 from d 3 to 7 (P<0.05). The ratios of Bcl-2 and Bax mRNA expression in embryos were higher on d 5 than on d 3 and 1 in PZM-3 (P<0.05). In contrast, the ratios of Bcl-2 and Bax mRNA expression in embryos on d 1 were higher than on d 3 and 5 in NCSU-23 (P<0.05). Additionally, the ratios of Bcl-2 and Bax mRNA expression in embryos in PZM-3 were higher than in NCSU-23 on d 3 and 5 (P<0.05). In conclusion, lower apoptotic embryo rates and down-regulating Bax together with up-regulating expression of Bcl-2 transcripts may be responsible for the better developmental competence of porcine parthenotes in PZM-3.