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Plant photosynthetic capacity directly determines crop yield. Light quality regulates photosynthetic capacity. This review discusses plant responses to far-red light from the phenotypic to the molecular level, focusing specifically on the improvement of photosynthetic capacity by adjustment of photosynthetic electron transport and the path of light energy. Far-red light can also regulate leaf angle and increase plant height and leaf area, via expression of associated genes, to capture more light energy. Thus, far-red light regulates plant morphology and photosynthetic capacity. Identifying the mechanism of this regulation may lead to increased crop yields.

Under natural conditions, plants constantly encounter various biotic and abiotic factors, which can potentially restrict plant growth and development and even limit crop productivity. Among various abiotic factors affecting plant photosynthesis, light serves as an important factor that drives carbon metabolism in plants and supports life on earth. The two components of light (light quality and light intensity) greatly affect plant photosynthesis and other plant’s morphological, physiological and biochemical parameters. The response of plants to different spectral radiations and intensities differs in various species and also depends on growing conditions. To date, much research has been conducted regarding how different spectral radiations of varying intensity can affect plant growth and development. This review is an effort to briefly summarize the available information on the effects of light components on various plant parameters such as stem and leaf morphology and anatomy, stomatal development, photosynthetic apparatus, pigment composition, reactive oxygen species (ROS) production, antioxidants, and hormone production.

Background Stomatal conductance is a limiting factor of plant photosynthesis. Studies on the influencing factors of stomatal conductance amongst different species are abundant, but the effect of leaf phenotype on stomatal conductance is usually ignored in study. Here, the experiment set different intensities monochromatic blue and red light. We investigated the upper and lower epidermis stomatal traits, leaf structure, the maximum operational stomatal conductance and net photosynthetic rate of soybean leaves. In addition, the contribution of leaf structure and stomatal characteristics to stomatal conductance was quantified by a new software package. Results In this study, net photosynthetic rate was tightly coupled with operational stomatal conductance, inhibited by red light and enhanced by blue light. Regardless of light environment, the maximum operational stomatal conductance was mainly affected by leaf thickness according to the analysis of contribution rate, rather than stomatal density of upper and lower epidermis. A significant positive correlation was found between leaf structure and stomatal density, but the correlation between stomatal density and stomatal size was not found. Regardless of the amounts of light intensities, stomatal density (SD), palisade tissue and specific leaf weight (SLW) were mainly regulated by blue light, whereas red light was more important to stomatal size and spongy tissue. Conclusions Although leaf thickness is more critical in affecting stomatal conductance than stomatal density, blue light mainly promotes leaf thickness and stomatal density, which coordinated each other to facilitate stomatal conductance, thereby positively regulating photosynthetic capacity.

Intercropping advantage occurs only when each species has adequate time and space to maximize cooperation and minimize competition between them. A field experiment was conducted for two consecutive years between 2013 and 2014 to investigate the effects of maize and soybean relay strip intercropping systems on the uptake and utilization of nitrogen, phosphorus, and potassium. The treatments included “40:160” (T1, maize narrow and wide row spacing of 40 and 160 cm, where two rows of soybean with a 40 cm row were planted in the wide rows. The area occupation ratio of maize and soybean both were 50% of the every experimental block), “80:120” (T2, maize narrow and wide row spacing of 80 and 120 cm, the soybean planting was the same as T1 treatment. The area occupation ratio of maize and soybean were 60% and 40% of the every experimental block), “100:100” (T3, one row of maize and one row of soybean with a 100-cm row. The area occupation ratio of maize and soybean was the same as T1 treatment), sole cropping of maize (CK1, The area occupation ratio of maize was 100% of the every experimental block), and sole cropping of soybean (CK2, The area occupation ratio of soybean was 100% of the every experimental block). The results show that, compared with the sole cropping system (sole maize), the economic yields in T1, T2, and T3 treatments increased by 761, 536, and 458 kg·ha−1, respectively, and the biological yields increased by 2410, 2127, and 1588 kg·ha−1. The uptake and utilization of nitrogen, phosphorus, and potassium in T1, T2, and T3 treatments were significantly higher than those in sole crops, and the nutrient advantage is mainly due to nutrient uptake rather than nutrient use efficiency. The land equivalent ratio values in T1, T2, and T3 treatments were 1.43, 1.32, and 1.20, respectively. In particular, the economic and biological yield in T1 treatment exhibited potential as an intercropping pattern.

Changes in leaf carbon and nitrogen traits are effective parameters for evaluating whether plants are growing normally and for guiding field management measures. Therefore, a nondestructive estimation of soybean leaf carbon content (LCC) and leaf nitrogen content (LNC) is important for managing soybean production. This study aims to investigate the properties of soybean LCC, LNC and leaf carbon and nitrogen ratio (LCNR) under different light conditions and to construct the estimation models for soybean LCC, LNC and LCNR on the basis of hyperspectral reflectance. A 3-year field trial was conducted from 2013 to 2015 to investigate the effect of five shade treatments (from 57% to 18% of normal photosynthetic active radiation) by regulating the distance between maize and soybean rows in an intercropping system. Results showed that the LNC is increased, and the LCC is decreased with the increase in shading level. A typical leaf hyperspectral reflectance showed that the changes in near infrared and around the green peak are approximately proportional to the LCC and analogously inverse to the LNC. The corresponding first-order derivative presented the changes in the red-edge positions as a ‘blue shift’ with the increase in shading level. General vegetation indices (VIs), uninformative variable elimination-partial least squares (UVE-PLS) and continuous wavelet transform (CWT) were used to develop the models. The linear models constructed using the CWT, compared with the VIs and UVE-PLS, had the highest determination coefficient and the lowest root mean square error (RMSE). The models were validated using independent data from 2015 with RMSE values of 1.9789, 0.6132 and 2.1587 for the LCC, LNC and LCNR, respectively. Moreover, these models obtained relative errors of 4.5%, 13.2% and 20% for the LCC, LNC and LCNR, respectively. Results indicated that soybean LNC and LCC can be accurately estimated using the CWT for assessing the physiological situation.

Maize shading affects the growth and development of soybean in maize soybean intercropping systems. Two different soybean varieties were (ND12, high shade-tolerant, and GX3, low shade-tolerant) relay intercrop with maize in different (T1, double row, and T2, single row) relay strip intercropping systems, and the results of the both planting arrangements of strip intercropping system were compared with the sole planting system of soybean. The results showed that shading reduced the content of photosynthetic pigment per unit area of soybean leaf, Fv/Fm, ΦPSⅡ, and Fv/Fo of ND12 and GX3 under T1 and T2. Moreover, T1 and T2 also decreased the density and size of stomata, leaf thickness, palisade tissue thickness of the tissue, and the size of the chloroplast and starch grains, while increased the thickness of the granum lamellae in both varieties of soybean. Nevertheless, the leaf area, aboveground biomass, photosynthetic capacity, photosynthetic organs measured morphological and architectural indices were found maximum in ND12 compared to GX3 in all planting patterns.

In order to solve the problem that carbonate rocks are difficult to be explored due to their complex heterogeneity, the evaluation of carbonate reservoirs and the prediction of gas bearing are carried out. Firstly, taking the Sugeri gas field area in Ordos as an example, the address characteristics of the research area are introduced. Then the petrological characteristics and reservoir spatial characteristics (pore types and pore structures) of carbonate reservoirs are explored. In addition, the prediction and simulation method of carbonate reservoir gas bearing—amplitude variation with offset (AVO) forward modeling analysis method is discussed. Finally, the results of reservoir characteristics and prediction of reservoir gas bearing are analyzed. The results show that there is no effective reservoir development in Ma Wu32, Ma Wu33, and Ma Wu41b in the study area, and Ma Wu41a is the main effective reservoir development segment, followed by Ma Wu2 subsegment. For gas bearing prediction, there are a total of 10 favorable zones in Ma Wu segment, among which the predicted gas thickness is between 2 and 8 m. The results have good guiding significance for oil and gas exploration in China.

Background Shading includes low light intensity and varying quality. However, a low red/far-red (R/Fr) ratio of light is a signal that affects plant growth in intercropping and close- planting systems. Thus, the low R/Fr ratio uncoupling from shading conditions was assessed to identify the effect of light quality on photosynthesis and CO2 assimilation. Soybean plants were grown in a growth chamber with natural solar radiation under four treatments, that is, normal (N, sunlight), N + Fr, Low (L) + Fr, and L light. Results Low R/Fr ratio significantly increased the total biomass, leaf area, starch and sucrose contents, chlorophyll content, net photosynthetic rate, and quantum efficiency of the photosystem II compared with normal R/Fr ratio under the same light level (P 2 assimilation in the chloroplast. Among the 7834 proteins quantified, 12 showed a > 1.3-fold change in abundance, of which 1 was related to porphyrin and chlorophyll metabolism, 2 were involved in photosystem I (PS I), 4 were associated with PS II, 3 proteins participated in photosynthetic electron transport, and 2 were involved in starch and sucrose metabolism. The dynamic change in these proteins indicates that photosynthesis and CO2 assimilation were maintained in the L treatment by up-regulating the component protein levels compared with those in N treatment. Although low R/Fr ratio increased the photosynthetic CO2 assimilation parameters, the differences in most protein expression levels in N + Fr and L + Fr treatments compared with those in N treatment were insignificant. Similar trends were found in gene expression through quantitative reverse transcription polymerase chain reaction excluding the gene expression of sucrose synthase possible because light environment is one of the factors affecting carbon assimilation. Conclusions Low R/Fr ratio (high Fr light) can increase the photosynthetic CO2 assimilation in the same light intensity by improving the photosynthetic efficiency of the photosystems.

Additional file 3: Table S2. List of primers for characterizing Glycine max genes.

Additional file 1: Figure S1. Light response curves of net photosynthetic rate (A), light saturation point (B), and quantum yield of PSII (C) of soybean leaves under different treatments. N, N + Fr, L + Fr, and L denote normal light (normal PAR and normal R/Fr ratio), normal light plus far-red light (normal PAR and low R/Fr ratio), low light plus far-red light (low PAR and low R/Fr ratio), and low light (low PAR and normal R/Fr ratio), respectively. Pmax and LSP represent the maximum photosynthetic rate and the light saturation point. Data are expressed as the means ± SD of triplicates. Means followed by different letters are significantly different at P = 0.05.

Photosynthesis is dependent on the density and quality of light that reaches chloroplasts. Shade conditions are characterized by changes in light density and quality. These changes, which are represented by the red to far-red (R/Fr) ratio of light, directly affect the photosynthetic capacity of soybean in close-planting and intercropping systems. We postulated that high far-red light under shade conditions would improve crop photosynthesis. Herein, we conducted a quantitative proteomic analysis through the isobaric tagging for relative and absolute quantification approach to investigate the response of photosynthetic proteins to the interaction between light intensity and quality. We identified 7834 proteins (P value 1.3) from soybean leaves. Among these proteins, 98 are associated with differential chloroplast accumulation under shade (S, low light intensity and low R/Fr ratio) and normal light (N, normal light intensity and normal R/Fr ratio) conditions. Additionally, 134 are associated with differential chloroplast accumulation under low light (L, low light intensity and normal R/Fr ratio) and N conditions. Eight representative proteins that are involved in photosynthesis were differentially regulated under L and S treatments. These proteins included one protein involved in porphyrin and chlorophyll metabolism, three proteins involved in light-harvesting chlorophyll protein complex, and four proteins involved in photosynthesis. Among the eight differentially regulated proteins under L and S treatments, five up-regulated proteins (protochlorophyllide reductase; light-harvesting complex II chlorophyll a/b binding protein [Lhcb1]; Lhcb2; photosystem I subunit II; and plastocyanin [PetE]) and three down-regulated proteins (Lhcb4; Ferredoxin-1; and NADPH:quinone oxidoreductase [NQO]) were validated through quantitative reverse-transcription polymerase chain reaction and Western blot methods L and S treatments decreased net photosynthesis rate (Pn) but increased chlorophyll content; thylakoid stacking; and photosystem II (PSII), PSI, and electron transport associated protein levels. Likewise, N and S treatments decreased PetE and NQO protein expression levels. This effect, in turn, decreased P700 oxidation. In addition, the higher far-red light of the S treatment than that of the L treatment increased Pn by up-regulating the gene expressions of differential proteins. We conclude that light intensity directly affects photosynthesis by regulating the expression of photosynthetic proteins. High far-red light, however, can improve the photosynthetic capacity of plants under shade conditions.

Soybean is one of the major oil seed crops, which is usually intercropped with other crops to increase soybean production area and yield. However, soybean is highly sensitive to shading. It is unclear if soybean morphology responds to shading (i.e., shade tolerance or avoidance) and which features may be suitable as screening materials in relay strip intercropping. Therefore, in this study, various agronomic characteristics of different soybean genotypes were analyzed under relay intercropping conditions. The soybean materials used in this study exhibited genetic diversity, and the coefficient of variations of the agronomic parameters ranged from 13.84 to 72.08% during the shade period and from 6.44 to 52.49% during the maturity period. The ratios of shading to full irradiance in stem mass fraction (SMF) were almost greater than 1, whereas opposite results were found in the leaves. Compared with full irradiance, the average stem length (SL), leaf area ratio (LAR) and specific leaf area (SLA) for the two years (2013 and 2014) increased by 0.78, 0.47 and 0.65 under shady conditions, respectively. However, the stem diameter (SD), total biomass (TB), leaf area (LA), number of nodes (NN) on the main stem, and number of branches (BN) all decreased. During the shady period, the SL and SMF exhibited a significant negative correlation with yield, and the SD exhibited a significant positive correlation with yield. The correlation between the soybean yield and agronomic parameters during the mature period, except for SL, the first pod height (FPH), 100-seed weight (100-SW), and reproductive growth period (RGP), were significant (P

Aboveground and belowground interactions are crucial in the over-yielding of intercropping systems. However, the relative effects of aboveground and belowground interactions on yields of intercrops in maize ( Zea mays L.) and soybean [ Glycine max (L.) Merr.] relay intercropping systems are still unclear. Field experiments, including measurements of biomass, grain yield, and photosynthetic parameters, were conducted in 2013–2014 to analyze the advantages and effects of aboveground and belowground of interspecies interactions on yield. To analyze the aboveground interactions of intercrops for light interception, this study adopted three different row configurations [(P1) “160 cm + 40 cm” and (P2) “120 cm + 80 cm” maize wide-narrow row planting, where two rows of soybean with a 40-cm row width were planted in the wide rows, and (P3) “100 cm +100 cm” maize equal-row planting, where one row of maize and one row of soybean with a 50-cm spacing between the adjacent rows of both crops]. Moreover, to identify interspecies belowground competition, no root separation (R1) and root separation (R2) were employed between adjacent maize and soybean rows. The photosynthetically active radiation (PAR) transmittances of maize wide-row were significantly higher than those of maize narrow-row at the sixth leaf stage (jointing stage), twelfth leaf stage (bell stage), and tasseling stage. Specifically, PAR transmittances decreased as maize narrow-row spacing increased. No significant differences in the PAR transmittances of maize narrow-row or wide-row were found between the R1 and R2 conditions. Similarly, no significant differences between intercrop biomass and grain yield were observed between the R1 and R2 conditions. By contrast, different row configuration treatments exhibited significant differences in biomass (whole growth period for soybean and after tasseling stage for maize), grain yield and photosynthetic parameters of intercrops. These results implied that aboveground interactions, such as mutual shading, have more significant contributions to intercrop advantages than belowground interactions. In addition, the intercropped maize yields increased as maize narrow-row spacing (from P1 to P3 treatment) increased. However, contrasting trends were found for intercropped soybean yield and land equivalent ration (LER). No significant differences in LER were observed between R1 and R2 conditions in different row configurations. P1 treatment exhibited the maximum LER (1.64 for 2013 and 1.83 for 2014) and mixed yield (7430 kg ha −1 for 2013 and 9559 kg ha −1 for 2014), but the lower maize yield compared with P2 and P3 treatments. This result suggested that reducing the competitive ability of maize while increasing that of soybean significantly improves intercropping advantage in maize-soybean relay intercropping systems.

Real-time PCR primers. (PDF 309 kb)

Background Intercropping and close planting are important cultivation methods that increase soybean yield in agricultural production. However, plant shading is a major abiotic stress factor that influences soybean growth and development. Although shade affects leaf morphological parameters and decreases leaf photosynthesis capacity, information on the responses of soybean leaf photosynthesis to shading at proteomic level is still lacking. Results Compared with leaves under normal light (CK) treatment, leaves under shading treatment exhibited decreased palisade and spongy tissue thicknesses but significantly increased cell gap. Although shade increased the number of the chloroplast, the thickness of the grana lamella and the photosynthetic pigments per unit mass, but the size of the chloroplast and starch grains and the rate of net photosynthesis decreased compared with those of under CK treatment. A total of 248 differentially expressed proteins, among which 138 were upregulated, and 110 were downregulated, in soybean leaves under shading and CK treatments were detected via isobaric tags for relative and absolute quantification labeling in the three biological repeats. Differentially expressed proteins were classified into 3 large and 20 small groups. Most proteins involved in porphyrin and chlorophyll metabolism, photosynthesis-antenna proteins and carbon fixation in photosynthetic organisms were upregulated. By contrast, proteins involved in photosynthesis were downregulated. The gene family members corresponding to differentially expressed proteins, including protochlorophyllide reductase (Glyma06g247100), geranylgeranyl hydrogenase (Ggh), LHCB1 (Lhcb1) and ferredoxin (N/A) involved in the porphyrin and chlorophyll metabolism, photosynthesis-antenna proteins and photosynthesis pathway were verified with real-time qPCR. The results showed that the expression patterns of the genes were consistent with the expression patterns of the corresponding proteins. Conclusions This study combined the variation of the soybean leaf structure and differentially expressed proteins of soybean leaves under shading. These results demonstrated that shade condition increased the light capture efficiency of photosystem II (PSII) in soybean leaves but decreased the capacity from PSII transmitted to photosystem II (PSI). This maybe the major reason that the photosynthetic capacity was decreased in shading. Electronic supplementary material The online version of this article (10.1186/s12870-019-1633-1) contains supplementary material, which is available to authorized users.

Different planting patterns affect the light interception of intercrops under intercropping conditions. Here we revealed that narrow-wide-row relay-intercropping improves the light interception across maize leaves in wide rows (60cm) and narrow rows (40cm), accelerated the biomass production of intercrop-species and compensated the slight maize yield loss by considerably increasing the soybean yield. In a two-year experiment, maize was planted with soybean in different planting patterns (1M1S, 50:50cm and 2M2S, 40:60cm) of relay-intercropping, both planting patterns were compared with sole cropping of maize (M) and soybean (S). As compared to M and 1M1S, 2M2S increased the total light interception of maize leaves in wide rows (WR) by 27% and 23%, 20% and 10%, 16% and 9% which in turn significantly enhanced the photosynthetic rate of WR maize leaves by 7% and 5%, 12% and 9%, and 19% and 4%, at tasseling, grain-filling and maturity stage of maize, respectively. Similarly, the light transmittance at soybean canopy increased by 218%, 160% and 172% at V2, V5 and R1 stage in 2M2S compared with 1M1S. The improved light environment at soybean canopy in 2M2S considerably enhanced the mean biomass accumulation, and allocation to stem and leaves of soybean by 168%, and 131% and 207%, respectively, while it decreased the mean biomass accumulation, and distribution to stem, leaves and seed of maize by 4%, and 4%, 6% and 5%, respectively than 1M1S. Compared to 1M1S, 2M2S also increased the CR values of soybean (by 157%) but decreased the CR values of maize (by 61%). Overall, under 2M2S, relay-cropped maize and soybean produced 94% and 69% of the sole cropping yield, and the 2M2S achieved LER of 1.7 with net income of 1387.7 US $ ha-1 in 2016 and 1434.4 US $ ha-1 in 2017. Our findings implied that selection of optimum planting pattern (2M2S) may increase the light interception and influence the light distribution between maize and soybean rows under relay-intercropping conditions which will significantly increase the intercrops productivity. Therefore, more attention should be paid to the light environment when considering the sustainability of maize-soybean relay-intercropping via appropriate planting pattern selection.

Predicting grain yield and protein content of maize using spectral reflectance data is very important for improved agricultural production. In this study, we predicted the grain yield and protein content of maize grown under different irrigation and nitrogen levels in 2018 and 2019 based on canopy spectral reflectance measurements at the V6 (sixth leaf), VT (tassel), and R2 (blister) stages. We developed a predictive approach, namely, spectral reflectance–physiological parameters–productivity, to predict grain yield and protein content on maize crop. First, the quantitative relationships between grain yield and protein content and physiological parameters (canopy chlorophyll content [CCC], leaf carbon accumulation [LCA], leaf nitrogen content [LNC], and leaf nitrogen accumulation [LNA]) were analysed. Then, vegetation indices (VIs) and wavelet features based on spectral reflectance were used to establish estimation models for physiological parameters. The physiological parameters were used as a bridge to connect the spectral reflectance data with grain yield and protein content. The purpose was to establish spectral inversion models to indirectly estimate grain yield and protein content. Results showed that grain yield had a significant linear relationship with CCC and LCA. In addition a grain protein content and LNC and LNA were also significantly related under different water, and nitrogen availability. The physiological parameter models with ratio vegetation indices (RVI), biorthogonal 3.3 (bior3.3), and reverse biorthogonal 1.5 (rbio1.5) were reliable in terms of predictability and applicability. Independent data verification suggested that grain yield was predicted using RVI769,758 (R2 = 0.773, RMSE = 2.509) in water availability, rbio1.5781,29 (R2 = 0.744, RMSE = 2.850) in nitrogen availability, and rbio1.5772,11 (R2 = 0.506, RMSE = 2.297) in water–nitrogen availability. In addition, the grain protein content was predicted using RVI793,757 (R2 = 0.704, RMSE = 0.744) in water availability, bior3.3743,19 (R2 = 0.717, RMSE = 0.957) in nitrogen availability, and RVI492,418 (R2 = 0.715, RMSE = 1.224) in water–nitrogen availability. Therefore, maize grain yield and protein content can be accurately predicted using our modelling approach.

Chunguang oilfield is a new focus of the exploration in Junnggar Basin with the heavy crude oil distributing in Jurassic, Cretaceous and Tertiary strata. Based on the analysis of the geochemistry and fluid inclusion in the reservoirs, the source, accumulated period and process of the heavy crude oil reservoir has been investigated. The results indicate that the heavy crude oil can be divided into three types based on the degradation and sources. The heavy crude oil was mainly derived from the Permian source rocks, and latterly mixed by the heavy crude oil generated by the Jurassic source rocks. The accumulated period of the heavy crude oil has two stages. One was ranged from Cretaceous to Paleogene and the heavy crude oil was sourced from Permian source rocks of the Shawan depression and latterly mixed by the heavy crude oil generated by the Jurassic source rocks. The second period was from Neogene to present and the heavy crude oil was mainly derived from the Jurassic source rocks. Combined with the geological evolution, the heavy crude oil accumulated process has been recovered.

Narrow-row planting patterns directly affect crop yield and competition in intercropping systems. A two-year (2012 and 2013) field experiment was conducted to determine the interactive behavior between intercrops in a maize–soybean relay strip intercropping system. Maize plants were planted in different narrow-wide row planting patterns, whereas soybean was planted in wide rows. The total biomass and grain yield of maize increased with increasing maize narrow-row spacing, but the opposite trend was observed for soybean. The aggressivity, competitive ratio, and partial relative crowding advantage values for maize were greater than those for soybean. Moreover, the competitive interaction of the intercrops was affected by the distance between maize and soybean rows. The highest intercrop land equivalent ratio (LER) 1.61 and 1.59 was found in the 40:160 planting pattern (i.e. 40 cm narrow-row spacing and 160 cm wide-row spacing of maize) during 2012 and 2013, respectively. Combined with actual yield loss and LER, the intense intra-specific competition of maize plants reduced the depression for the associated soybeans when the maize narrow-row spacing was less than 30 cm. When the narrow-row spacing was wider than 50 cm, soybean growth was seriously depressed by maize because of the stronger inter-specific competition between maize and soybean. The maximum yield and economic advantage appeared in the 40:160 narrow-wide row planting pattern. Therefore, intercropping advantage may be achieved by changing the row spacing and distance between intercrop rows to coordinate the inter-specific competition between maize and soybean.

Objective This experiment was conducted as a 3×2×2 factorial design to examine the effects of particle size (mean particle size of 331, 640, or 862 μm), evaluation method (direct vs indirect method) and adaptation duration (7 or 26 days) on the energy content and the apparent total tract digestibility (ATTD) of various chemical components in wheat when fed to finishing pigs. Methods Forty-two barrows (Duroc×Landrace×Yorkshire) with an initial body weight of 63.0±0.8 kg were individually placed in metabolic cages and randomly allotted to 1 of 7 diets with 6 pigs fed each diet. For the indirect method, the pigs were fed either a corn-soybean meal based basal diet or diets in which 38.94% of the basal diet was substituted by wheat of the different particle sizes. In the direct method, the diets contained 97.34% wheat with the different particle sizes. For both the direct and indirect methods, the pigs were adapted to their diets for either 7 or 26 days. Results A reduction in particle size linearly increased the digestible energy (DE) and metabolizable energy (ME) contents as well as the ATTD of gross energy, crude protein, organic matter, ether extract (EE) and acid detergent fiber (ADF) (p

Estimation of photosynthetic pigments status using hyperspectral remote sensing technology is highly significant for the effective evaluation of maize (Zea mays L.) productivity. Effective mathematical statistics and modeling methods can improve the accuracy and reliability of pigment contents. In this study, field experiments were conducted with different water and nitrogen levels to develop a quantitative assessment model that determines chlorophyll (Chl) and carotenoids (Car) contents in maize. A pigment prediction model was established by vegetation indices (VIs), wavelet feature, uninformative variable elimination (UVE), and UVE based on continuous wavelet transform (CWT-UVE) and then compared with various methods. The wavelet feature db1 of maize leaf reflectance had a better correlation with Chl and Car with correlation coefficients (r) of −0.9247 and −0.8705, respectively. By using a calibration set, the best results for monitoring the Chl and Car status were observed using the rbio3.3-UVE-PLS, which indicated fewer variables. The R2 and RMSE were respectively 0.9435 and 0.0937 for Chl, 0.8807, and 0.0130 for Car. In addition, tests conducted on the independent validation set showed that rbio3.3-UVE-PLS could be used to estimate the Chl (R2 = 0.8534; RMSE = 0.1773; RPD = 2.6458), and bior3.3-UVE-PLS can be used to estimate the Car (R2 = 0.8299; RMSE = 0.0187; RPD = 2.3832). Thus, Chl and Car are accurately monitored with the CWT-UVE-PLS method. This study provides an important support method for the practical application of photosynthetic pigment contents analysis in maize.

Based on molecular and stable carbon isotope composition of a large collection of gas samples and integrated with the geological context, this article discusses the genesis and migrational characteristics of natural gases from the giant tight sand gas fields of the Upper Paleozoic strata, Ordos Basin (UPOB). Our results show that the UPOB gas is mostly derived from coaly source rocks, with a minor contribution of oil-associated gas probably from the interbedded carbonate source rocks. Gas isotope data suggest that the Yulin–Zizhou gas field was likely formed from a single gas charge with no significant alteration, whereas the Sulige field contains a mixture of gases from successive charges with multiple maturity levels. The geographical variation in the observed gas composition is attributed primarily to the effect of source rock maturity, with no explicit geochemical fractionation caused by long distance lateral migration.

Intercropping is an important agronomic practice adopted to increase crop production and resource efficiency in areas with intensive agricultural production. Two sequential field trials were conducted in 2015–2016 to investigate the effect of shading on the morphological features, leaf structure, and photosynthetic characteristics of soybean in a maize-soybean relay-strip intercropping system. Three treatments were designed on the basis of different row configurations A1 (“50 cm + 50 cm” one row of maize and one row of soybean with a 50 cm spacing between the rows), A2 (“160 cm + 40 cm” two rows of maize by wide-narrow row planting, where two rows of soybean were planted in the wide rows with a width of 40 cm, and with 60 cm row spacing was used between the maize and soybean rows), and CK (sole cropping of soybean, with 70 cm rows spacing). Results showed that the photosynthetically active radiation transmittances of soybean canopy at V5 stage under A2 treatment (31.1%) were considerably higher than those under A1 (8.7%) treatment, and the red-to-far-red ratio was reduced significantly under A1 (0.7) and A2 (1.0) treatments compared with those under CK (1.2). By contrast with CK, stem diameter, total aboveground biomass, chlorophyll content and net photosynthetic rate decreased significantly except plant height under A1 and A2. The thickness of palisade tissue and spongy tissue of soybean leaf under A1 and A2 were significantly reduced at V5 stage compared with CK. The leaf thicknesses under A1 and A2 were lower than those in CK by 39.5% and 18.2%, respectively. At the R1 stage of soybean (after maize harvest), the soybean plant height, stem biomass, leaf biomass and petiole biomass under A1 and A2 treatments were still significantly lower than those under CK, but no significant differences were observed in Chl a/b, Pn, epidermis thickness and spongy tissue thickness of soybean leaves in A2 compared with CK. In addition, the soybean yields (g plant-1) under A1 and A2 were 54.69% and 16.83% lower than those in CK, respectively. These findings suggested that soybean plants can regulate its morphological characteristics and leaf anatomical structures under different light environments.

OBJECTIVE Two experiments were conducted to determine the effects of adding exogenous phytase and xylanase, individually or in combination, as well as pelleting on nutrient digestibility, available energy content of wheat and the performance of growing pigs fed wheat-based diets. METHODS In Experiment 1, forty-eight barrows with an initial body weight of 35.9±0.6 kg were randomly assigned to a 2×4 factorial experiment with the main effects being feed form (pellet vs meal) and enzyme supplementation (none, 10,000 U/kg phytase, 4,000 U/kg xylanase or 10,000 U/kg phytase plus 4,000 U/kg xylanase). The basal diet contained 97.8% wheat. Pigs were placed in metabolic cages for a 7-d adaptation period followed by a 5-d total collection of feces and urine. Nutrient digestibility and available energy content were determined. Experiment 2 was conducted to evaluate the effects of pelleting and enzymes on performance of wheat for growing pigs. In this experiment, 180 growing pigs (35.2±9.0 kg BW) were allocated to 1 of 6 treatments according to a 2×3 factorial treatment arrangement with the main effects being feed form (meal vs pellet) and enzyme supplementation (0, 2,500 or 5,000 U/kg xylanase). RESULTS In Experiment 1, there were no interactions between feed form and enzyme supplementation. Pelleting reduced the digestibility of acid detergent fiber (ADF) by 6.4 percentage units (p

Dietary energy source can influence muscle glycogen storage at slaughter. However, few studies have demonstrated whether the diet-induced change of muscle glycogen is achieved by the transformation of muscle fibre type. This study investigated the effects of dietary energy sources on meat quality, post mortem glycolysis and muscle fibre type transformation of finishing pigs. Seventy-two barrows with an average body weight of 65.0 ± 2.0 kg were selected and were allotted to three iso-energetic and iso-nitrogenous diets A, B or C, and each treatment consisted of three replicates (pens) of eight pigs each. Diet A contained 44.1% starch, 5.9% crude fat and 12.6% neutral detergent fiber (NDF); diet B contained 37.6% starch, 9.5% crude fat and 15.4% NDF; and diet C contained 30.9% starch, 14.3% crude fat and 17.8% NDF. The duration of the experiment was 28 days. After feed withdrawal 12 h, 24 pigs (eight per treatment) were slaughtered, samples from M. longissimus lumborum (LL) were collected for subsequent analysis. The results showed that pigs fed diet C had lesser average daily gain, average daily feed intake and back fat depth than those fed diet A (P

More than 156 marine paleo-reservoirs (or residual oil reservoirs) and hydrocarbon shows are found in the Neoproterozoic, Paleozoic and Mesozoic marine strata of the northern margin of the Jiangnan-Xuefeng uplift, southern China. In this paper, the characteristics and distributions of marine paleo-reservoirs are statistically analyzed. It is suggested that paleo- reservoirs and hydrocarbon shows were controlled by the ancient uplift and its tectonic evolution. These paleo-reservoirs and hydrocarbon shows in different marine strata have different characteristics and distributions. Paleo-reservoirs and bituminous shows appear mainly in the Ediacaran system of the Neoproterozoic and Lower Paleozoic, and oil and gas shows occur predominantly in the Permian and Triassic, which is obviously related to the development of source rocks and thermal evolution of hydrocarbon. The paleo-reservoir bitumen and hydrocarbons fill predominantly in the fractures and pores of carbonate and clastic reservoirs, which are controlled by the characteristics of original reservoirs and their succeeding transforma- tion with the tectonic evolution, respectively. As estimated by the reservoir scale sequential method, the marine strata hold approximately 368 × 10 8 tonnes of total geological reserves in place of an initial crude oil in the northern margin of the Jiangnan-Xuefeng uplift.