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To explore the presence and concentrations of negatively charged oxygen ions in the atmosphere in a typical farming-pastoral ecotone, and reveal the effects of negatively charged oxygen ions on meteorological and air pollution parameters, including air pressure, air temperature, wind speed, precipitation, O3, and SO2, differences in negatively charged oxygen ion concentrations in different atmospheres and different underlying surfaces were compared to provide a decision-making basis for ecological protection and economic construction. Kruskal-Wallis test and Spearman analysis were used to statistically assess relationships. The results showed that: 1) air concentrations of negatively charged oxygen ions were highest at 06:00, and lowest at 14:00 – 15:00, with significant differences in negatively charged oxygen ion concentrations (P < 0.05) under different surface and environmental conditions, and seasonal variations, and 2) negatively charged oxygen ion concentrations display obvious inter-monthly variation, representing a normal distribution, with August as the center of the time span from June to October. Concentrations of negatively charged oxygen ions from July to August were the highest in the year, with little fluctuation from December to April. 3) a negative correlation was observed between diurnal variation in air temperature and negatively charged oxygen ion concentrations and a positive correlation was observed between monthly variations in air temperature and negatively charged ion concentrations. Negatively charged oxygen ion concentrations correlated positively with relative humidity, and negatively with wind speed. Concentrations did not change with time scale. Monthly variation in negatively charged oxygen ion concentrations correlated positively with precipitation, but not with air pressure or sunshine hours. 4) the daily mean concentration of negative oxygen ions correlates negatively with PM 10, CO, SO2, NO2, and O3, and seasonal differences were observed. No correlation with PM 2.5 was noted.
To evaluate the potential for Cd-polluted soil remediation by Salix integra under Cd stress, plant growth, physiological characteristics, Cd absorption, and transportation characteristics were observed. S. integra seedlings were employed as experiment materials; plant growth, root configuration, physiological responses of roots and leaves, and Cd absorption and transportation were investigated under different Cd stress concentrations (0, 10, 20, 30, 40 mg·L−1) using hydroponic equipment. The results showed that S. integra has good Cd tolerance, and the absorbed Cd is mainly concentrated in the shoot, and is highest in leaves and lowest in the stem. The transport coefficient increases while the enrichment coefficient gradually decreases with the increase in Cd concentration. Cd stress had a stimulating effect on root architecture, and the number of nodes and root tips increased significantly (P < 0.05). In addition, a low level of Cd (10 mg·L−1) stress enhanced the biomass and total root length, and a high level of Cd (40 mg·L−1) stress decreased root biomass. At the same time, the superoxide anion activity unit and CAT activity in roots and leaves were induced by Cd stress, but GSH content and GR activity were significantly decreased with increasing Cd concentration (P < 0.05). In conclusion, S. integra has good tolerance and enrichment characteristics for Cd stress, and has high Cd pollution remediation potential by promoting root growth and activating the antioxidant enzyme system.
Crude protein (CP) is an important index for evaluating forage quality. Rapid determination of the crude protein content of forage grass may provide a scientific basis for monitoring forage quality using remote sensing. The canopy reflectance of the dominant species Pennisetum alopecuroides in the semi-captive area of the Jiangsu Dafeng David’s Deer Reserve was measuerd using a back-held Field Spec Pro FR2500 hyperspectrograph, and the crude protein content was determined. Pre-processed spectral reflectance and spectral indices correlating significantly with crude protein content were selected to establish the partial least squares regression (PLSR) and stepwise multiple linear regression (SMLR) models. The PLSR model based on significant bands showed excellent accuracy for predicting crude protein content (R2 = 0.897, RMSE = 1.303, RPD = 3.11 in the validation set), whereas the SMLR model had the lowest degree of accuracy in the validation set (R2 = 0.17, RMSE = 3.691, RPD = 1.098). The predictive ability was similar between PLSR and SMLR models based on significant spectral indices, with RPD reaching approximately 2. The PLSR model based on significant bands yielded the most accurate model, which can quantitatively predict the crude protein content of P. alopecuroides in a large area in the reserve.
To evaluate the contribution of mixed planting Vicia sativa to Avena sativa grassland in reducing the use of nitrogen fertilizer and improving fertilizer efficiency, a two-factor [nitrogen application levels (no nitrogen application, N0; low nitrogen N20, 20 g ·m−2; high nitrogen N40, 40 g·m−2] and mixed sowing ratios (grass ꞉ legume = 100 ꞉ 0, 75 ꞉ 25, 50 ꞉ 50, 25 ꞉ 75, 0 ꞉ 100) field experiment under controlled conditions was performed in the Zhaosu Basin of Xinjiang in 2019. The forage yield, nitrogen yield, and interspecific competition pattern of mixed grassland were analyzed, and the nitrogen reduction potential of mixed Vicia sativa on Avena sativa grassland was evaluated from the perspective of nitrogen yield. The results showed that: 1) Avena sativa yield, total forage yield, Avena sativa nitrogen yield, and total nitrogen yield increased significantly with an increase in nitrogen level (P < 0.05); however, the yield and nitrogen yield of Vicia sativa did not change significantly. At various levels of nitrogen application, the ratio of grass to legume 75 ꞉ 25 treatment had a higher total forage yield, and it also had a higher Avena sativa nitrogen yield under N0 and N20. The mixed sowing was advantageous, and the nitrogen application level had no significant effect on it. 2) Under N0, the relative yield, nitrogen competition rate, and crowding rate of Vicia sativa were higher than those of Avena sativa and it were strong competitors in relative yield, nitrogen competition rate and crowding rate, while under N20 and N40, Avena sativa became a strong competitor. With a decrease in the mixed ratio, the relative yield, nitrogen competition rate, and crowding rate of Vicia sativa showed an increasing trend. The comparable yield, nitrogen competition rate, and crowding rate of Vicia sativa were negatively correlated with Avena sativa yield, total forage yield, and Avena sativa nitrogen yield. 3) Compared with unicast Avena sativa, mixed sowing Vicia sativa can replace 33.65%～45.15% of nitrogen fertilizer; under N0, the contribution of mixed Vicia sativa to Avena sativa grassland was 0.45～1.28 g·m−2; under N40, the promoted effect of mixed sowing of Avena sativa on Vicia sativa was 3.75 g·m−2; the increase in the yield due to applying nitrogen fertilizer was 3.71 g·m−2. Therefore, the mixed grassland of Avena sativa and Vicia sativa in the Zhaosu area can reduce nitrogen and increase yield. The change in interspecific competition pattern has little effect on the advantages of mixed sowing and the contribution of nitrogen reduction and efficiency.
This experiment used the plate separation method to isolate and identify Trichoderma strains with better salt tolerance from the collected saline grassroots soil, and evaluated their salt tolerance by simulating salt stress conditions with different concentrations of NaCl solution. Four strains of Trichoderma were isolated and purified, among which Trichoderma T-B strain had a higher salinity tolerance potential than the other three Trichoderma strains isolated. The morphological and molecular methods of fungal identification confirmed that the isolated Trichoderma T-B strain was T. longibrachiatum. Using different concentrations of NaCl solution to simulate salt stress conditions, there was no significant difference in the growth rate at 100 mmol·L−1 NaCl compared with the control at a culture period of 3～7 days (P > 0.05). However, spore production increased by 9.17%, which was significantly higher than that of the control (P < 0.05). Therefore, T. longibrachiatum was a strong saline-tolerant species, and the results provide a theoretical basis for using Trichoderma to control soil salinization.
To study the invasive plant species Plantago virginica, whole plant excavation was performed in locations supporting plants at different population densities (30, 100, and 220 plants·m−2). Differences and trade-off characteristics of biomass allocation between roots, leaves, and reproductive organs, and allometric relationships correlating with different plant densities were systematically analyzed. The results indicate that biomass and allocation ratios differed significantly (P < 0.05) at the three different densities of P. virginica, revealing that individual organ biomass, single leaf biomass, total biomass, leaf or root allocation ratio, and root to shoot ratio decreased with increasing plant density, revealing obvious density-dependent effects. By contrast, the reproductive allocation ratio and reproduction to leaf ratio increased significantly with increasing density (P < 0.05), indicating that high density prompts P. virginica to allocate more resources for reproduction. Significant allometric relationships among organ biomasses of P. virginica were detected at the three different densities (P < 0.05). Most of these relationships were allometric, with a ≠ 1.0. Increasing plant density of P. virginica could enhance biomass allocation to photosynthetic organs, and reduce reproductive biomass allocation. By adjusting the resource allocation rate and ratio between above ground and underground photosynthetic and reproductive organs, P. virginica could improve its adaptability to increased pressure of intraspecific competition. These results indicate strong resource allocation plasticity, which may be an important contributor to its high invasive capability. These results provide basic data for further elucidation of the reproductive strategies and invasion mechanisms of P. virginica.
In order to explore the influence of habitat on growth and biomass allocation and the trade-offs for the ramets of Phragmites australis, a comparative study was performed on quantity characteristics, biomass allocation, and growth relationship of ramets of P. australis in different habitats in Zhalong wetland using a large sample survey and statistical analysis. The results showed that during the vegetative growth period of July, the height and weight of ramets and weight of modules of P. australis in these four habitats were largest in the aquatic habitat and smallest in the saline-alkali habitat. The difference between habitats reached a significant level (P < 0.05); the maximum values of height and weight of ramets were 2.7～4.5 times and 4.9～18.8 times the minimum values within the habitat, and 2.9～4.6 times and 3.6～4.6 times among habitats, respectively. The coefficient of variance of ramet height among habitats (48.05%) was higher than that within habitat (24.87%～40.51%), and the coefficient of variance of ramet weight and the module between habitats (42.26%～64.09%) was lower than that within habitat (55.79%～99.76%). The biomass allocation ratios of leaves, leaf sheaths, and stems ranged from 27.79%～38.29%, 17.93%～25.66%, and 36.05%～54.14%, respectively. The relationship between ramet height and leaf weight, leaf sheath weight, stem weight, and ramet weight was a power function allometric scaling relationship, while the relationship between ramet weight and leaf weight, leaf sheath weight, and stem weight was a linear function isokinetic scaling relationship. The ramets of P. australis in different habitats had greater ecological plasticity with increasing height and weight. The growth of ramets was controlled by both genetic and environmental factors, and the growth relationships among the modules were highly conservative. This indicates there was a significant relationship between resource allocation and trade-offs among different modules of ramets of P. australis in different environments.
This study aimed to explore the evolutionary significance of flowering phenology and floral longevity of Stellera chamaejasme by measuring the flowering phenology and floral longevity at different biological levels (i.e., single flowers, inflorescences, and individual) in a natural population in the alpine grasslands on the eastern edge of the Qilian Mountains. The results showed that the studied population of S. chamaejasme flowered from mid-June to late July, and the flowering durations at the levels of population, individual, and inflorescence were 35 d, 18.97 d, and 9.80 d, respectively. The indexes of flowering synchrony at the individual and inflorescence levels were 0.86 and 0.78, respectively, with only one flowering peak at each level. The floral longevity at both the individual and inflorescence levels was significantly negatively correlated with the first flowering date. The floral longevity of single flowers significantly differed with position on an inflorescence; it was the longest for marginal flowers, shorter for flowers in the middle of the head, and the shortest for top flowers (i.e., flowers at the center of the inflorescence). In conclusion, S. chamaejasme was characterized by a “mass-flowering pattern,” and the floral longevity varied with flowering time and flower position on an inflorescence. This was likely an adaptive strategy of the species to maximize reproductive fitness in harsh alpine environments.
Glycerol-3-phosphate acyltransferase (GPAT) is a rate-limiting enzyme in the biosynthesis of triacylglycerol (TAG). GPAT catalyzes the initial step of TAG biosynthesis, provides substrates for synthesis of a variety of lipids, and is directly involved in plant growth, plant development, and stress resistance. Medicago truncatula, a leguminous model plant, has the characteristics of a small genome, short growth cycle, and high genetic transformation efficiency. Thus, the genome of M. truncatula was selected as the research object in this study to understand the role of the GPAT gene in alfalfa stress resistance, especially in salt tolerance. Twenty-four mtGPAT genes were identified from the genome of M. truncatula by BLASTp and HMM domain searches. According to the phylogenetic analysis, gene structure, and domain differences, the genes can be divided into three subfamilies. Chromosome mapping analysis showed that 24 mtGPAT genes were unevenly distributed on 7 alfalfa chromosomes, and 2～5 genes were distributed on each chromosome. Finally, gene expression pattern analysis showed that the GPAT gene of M. truncatula was organ-specific and involved in salt stress response. These results can provide a theoretical basis for further study of the function of GPAT family genes in M. truncatula.
To breed Coix lacryma-jobi for feed, 51 germplasm resources were analyzed for their crude protein, crude fiber, ash, crude fat, calcium, phosphorus, fresh grass yield, plant height, stem thickness, and tiller total. Fuzzy membership function, correlation analysis, principal component analysis, and cluster analysis were used to evaluate these traits, and the following results were obtained. (1) The cumulative contribution rate of the four main factors, namely yield, mineral, crude ash, and crude fat, to the total variation reached 66.16%. (2) The 51 C. lacryma-jobi germplasms were systematically clustered into three categories. Of these, 10 germplasms with high comprehensive quality evaluation scores were selected (Longhui coix, YY03-02, Xiaoheike, YY-37, YY-21, YY17-32, YY17-07, YY03-09, YY17-12, and YY17-03). The present study offers germplasm materials and theoretical support for the selection of C. lacryma-jobi varieties with excellent agronomic and quality traits suitable for production in Hunan.
White clover (Trifolium repens ‘Haifa’) was selected as experimental material, and the effects of soaking seeds in diethyl aminoethyl hexanoate (DA-6) on tolerance of chromium (Cr) stress during germination were studied. The results showed that a 5 mmol·L−1 Cr6+ solution significantly inhibited seed germination (P < 0.05). DA-6 at 40～60 mmol·L−1 significantly increased the germination index of white clover under chromium stress (P < 0.05), and the greatest effect was achieved at a concentration of 60 mmol·L−1. Moreover, free proline and soluble sugar increased by 1.6 and 3.8 times, respectively, and cell osmotic potential was significantly decreased by 178% for seeds soaked in DA-6 during germination under Cr6+ stress (P < 0.05). The antioxidant enzyme activity and key enzymes involved in the ascorbate-glutathione metabolism cycle of seeds soaked in DA-6 significantly increased (P < 0.05), thereby reducing oxidative damage and improving cell membrane stability during germination under Cr6+ stress. These results indicate that DA-6 significantly improves the seed germination rate and Cr6+ tolerance of white clover during germination and early development, which are closely associated with enhancement of osmotic adjustment and improvement of antioxidant defense.
In this study, endophytic bacteria were isolated from the stems and roots of alfalfa (Medicago sativa) and the antagonistic effects of these bacteria against the fungal pathogens Fusarium chlamydosporum, F. oxysporum, F. solani, F. oxysporum, F. avenaceum, and F. acuminatum were evaluated using the flat confrontation method. Selection of endophytic bacteria with excellent antagonistic activities was based on morphology and sequence analyses of 16S rDNA, and for the identified strains, we established biological functions and quantitively determined the effects on the ability to fix nitrogen, solubilize phosphorus (inorganic phosphorus), and secrete auxins. We succeeded in isolating 80 strains of endophytic bacteria from the stems and roots of alfalfa, among which, 39 strains showed more than 50% inhibition against F. chlamydosporum. Moreover, nine of these strains, namely, MS-43 (63.96%), MS-40 (63.75%), MS-46 (63.54%), MS-2 (63.13%), MS-31 (62.29%), MS-52 (62.08%), MS-80 (61.88%), MS-55 (61.46%), and MS-33 (61.25%), showed more than 61% inhibitory activity. In addition, the inhibitory activities of strains MS-40, MS-43, MS-46, and MS-50 against the other six assessed strains of Fusarium spp. were all higher than 60%. The average inhibition rate of MS-43 was 66.11% and this strain was also characterized by nitrogen fixation and IAA functions. On the basis of culture and morphological characteristics and 16S rDNA sequence, MS-43 was identified as a strain of Paenibacillus.
The rotation of alfalfa (Medicago sativa) and rice (Oryza sativa) is a new model for alfalfa plantations in southern China and many key technologies need to be studied. The effects of using fertilizer (basal and topical applications) and alfalfa green manure on plant growth and soil nutrient content in the alfalfa-rice rotation system were studied in winter fallow paddy soil. The results showed that nitrogen, phosphorus and potassium (NPK) fertilizer application greatly increased alfalfa growth, with biomass yield increasing by 22.6% and 41.9%, compared with no-fertilizer, when 225 and 450 kg·ha−1 NPK, respectively, were applied basally. The yield increased further when this was combined with a topical application of NPK, reaching 11 198 kg·ha−1 in early May of the following year under a combined basal (450 kg·ha−1 NPK) and topical (450 kg·ha−1 NPK) application treatment. An increase in shoot numbers was one of the main reasons for the increased yield. The increase in total N, available P, and organic matter in soil 0 – 20 cm was significant (P < 0.05) for the combined basal and topical application; the increase in the protein and P content of the alfalfa plants were also significant (P < 0.05), particularly for a combined basal and topical application at 450 kg·ha−1. The increase in K content was significant (P < 0.05) for both the basal and topical application; however, the latter increased the translocation of K from the shoots to leaves to a significant degree (P < 0.05). The increase in rice growth with the application of alfalfa green manure was significant (P < 0.05), with grain yield increasing by 18.2% compared to the treatment of not planted with alfalfa and not fertilized with green manure. The results indicate that an alfalfa-rice rotation is a highly efficient system that can produce a high yield of alfalfa while also increasing rice grain yield and alleviating soil nutrient levels. The alfalfa-rice model provides an effective way to develop alfalfa cultivation in southern China.
To screen gramineous forage varieties with strong cold resistance, the physiological responses of Elymus sibiricus ‘Qingmu No. 1’, E. sibiricus ‘Tongde’, E. breviaristatus ‘Tongde’, Poa crymophila ‘Qinghai’, P. pratensis var. anceps Gaud ‘Qinghai’, and Festuca sinensis ‘Qinghai’ seedlings to low-temperature stress were studied, and a comprehensive evaluation of the cold resistance of the six grasses was conducted based on subordinate function values analysis. The results showed that low-temperature stress inhibited the growth of the six grasses to different extents. The decrease rate in the fresh weight of P. crymophila ‘Qinghai’ was the lowest, whereas the rate of decrease in the dry weight of E. sibiricus ‘Qingmu No. 1’ was the lowest. Under low-temperature stress, the chlorophyll content of the six grasses decreased to different degrees, whereas the malondialdehyde content, superoxide dismutase activity, soluble sugar content, and proline content increased to different extents. Based on the comprehensive evaluation using subordinate function values analysis, the order of cold resistance of the six grasses was as follows: E. sibiricus ‘Qingmu No. 1’ > F. sinensis ‘Qinghai’ > P. crymophila ‘Qinghai’ > P. pratensis var. anceps Gaud ‘Qinghai’ > E. breviaristatus ‘Tongde’ > E. sibiricus ‘Tongde’. Therefore, E. sibiricus ‘Qingmu No. 1’ has the strongest cold resistance among the six gramineous forages.
This study explored planting patterns appropriate for the Diqing Tibetan Autonomous Prefecture in Yunnan. For this, 11 varieties of triticale and 3 varieties of rye were sown in autumn in Xiaozhongdian town in Shangri-La City. Factors such as plant height, yield, stress resistance, and nutrient quality of the trial varieties were evaluated. The results showed the following. 1) There was a significant difference (P < 0.05) in yield and stress resistance among the trial varieties of triticale and rye; the latter demonstrated the lodging phenomenon but the former did not. The fresh weight of the ‘Zhongsi No.1048 ’, ‘C6’, ‘Youneng’, and ‘Jisi No.3’ varieties were significantly higher (P < 0.05) than other varieties at 28.0 t·ha−1, 27.3 t·ha−1, 26.9 t·ha−1, and 26.0 t·ha−1, respectively. 2) There were several differences in the nutrient quality among the trial varieties. The crude protein content of ‘C35’, ‘Youneng’, ‘Jisi No.2’, ‘C10’, and ‘C16’ were greater than 7.03%; this was a higher than in all other varieties. The soluble sugar contents of the trial triticale varieties were significantly higher than those of the trial rye varieties (P < 0.05). 3) Comprehensive evaluation of forage yield, nutrient quality of the whole plant, and stress resistance showed that the varieties appropriate for autumn-sowing in the Diqing alpine region were the ‘Jisi No.2’, ‘Youneng’, ‘Jisi No.3’, ‘Gannong No.2’, and ‘Zhongsi No.1048’ varieties of triticale; these can be used in a rotation system with summer-sown silage corn in the high-elevation and alpine areas of Diqing. This is because the autumn-sown triticale and summer-sown silage corn used croplands that were left fallow over winter and changed the traditional planting pattern of “one ripe one year” to a planting pattern of “three ripe two years.” This balanced with the high-quality forage provided year-round for yaks that fed locally and alleviated the worry about grass supply and livestock numbers in the high-elevation and alpine areas of Diqing.
This study used pot experiments to explore how the growth and other photosynthetic physiological characteristics of Leymus chinensis responded to applications of phosphorus at four intensities (0, 70, 140, and 210 kg·ha−1). The results showed the following. 1) Applications of phosphorus at rates ranging from 70～210 kg·ha−1 increased the height and biomass accumulation of L. chinensis plants; the effects were most obvious at an application intensity of 140 kg·ha−1. 2) The photosynthetic response of L. chinensis to different soil phosphorus application intensities varied. As the intensity of the phosphorus applied increased, the net photosynthetic rate first increased and then decreased. The maximum photochemical efficiency (Fv / Fm), PSⅡ activity, and initial fluorescence (Fo) of chlorophyll fluorescence occurred when phosphorus application intensity ranged from 70～140 kg·ha−1, while Fo / Fm was at its minimum in these circumstances. An analysis of the fitted equation showed that a phosphorus application intensity of 148.75 kg·ha−1 was the most favorable for the accumulation biomass by L. chinensis.
To comprehensively understand the current research status and frontier development trends in plant polyploid induction and to obtain a better understanding of the latest research trends, we collected data from China National Knowledge Infrastructure (CNKI) and Web of Science (WOS) from 2000 to 2020. The literature on polyploid induction was systematically analyzed in terms of publication trends, frequency of citations, countries, periodicals, institutions, keywords, and burst terms. The analysis results show that in the research of plant polyploid induction, China, the United States, and Japan have made the most outstanding contributions. Most of this research focused on polyploid induction and identification methods. Of all the research institutions, Beijing Forestry University has the largest number of publications by far. Among these publications, “Euphytica” is in a leading position. Based on the research results of polyploid induction on a global scale and a comprehensive analysis of the hotspots and frontiers in this field, future research should focus on solving the following problems: 1) standardizing the evaluation procedure of polyploid induction, 2) solving the mosaic phenomenon during induction, and 3) achieving an in-depth understanding of the relationship between genome changes and new phenotype expression after polyploidization.
The objective of this study was to determine the energy and protein requirements of Qianbei brown goats during early gestation. Thirty-six 2nd parity Qianbei brown goat ewes with similar body weight [(27.45 ± 0.29) kg] and gestation times [(30 ± 3) d] were randomly divided into four groups each including three replicates with three goats per replicate. Ewes were fed 60%, 80%, 100%, and 120% of nutrient requirements. After 10 d of adaptation, all ewes were fed for 30 d while collecting their feces and urine output to measure nutrient utilization during the final 7 d of the 30 day feeding period. Regression equations fitting energy/protein intake and body-weight/daily gain were established to estimate energy and protein requirements for maintenance and growth of Qianbei Brown goats during early gestation. Gross energy intake (GEI), digestible energy intake (DEI), metabolizable energy intake (MEI), crude protein intake (CPI), digestible protein intake (DCPI), and metabolizable protein intake (MPI) in Qianbei brown goats improved with increasing nutrient levels, and average daily body weight gain (ADG) of Qianbei brown goats also increased. ME requirements for maintenance (MEm) and growth (MEg) of Qianbei brown goats in early gestation were 447.10 kJ·kg−1 BW0.75 and 29.80 kJ·g−1, respectively. DCP requirements for maintenance (DCPm) and growth (DCPg) were 2.75 g·kg−1 BW0.75 and 0.22 g·g−1, respectively. In conclusion, nutrient intake and growth were enhanced with increasing nutrient levels, and both energy and protein maintenance and growth requirements of goats were similar to those recommended by the USA National Research Council.
This study used a series of bioassays to examine the efficiency of using 5 species and 10 indigenous isolates of entomopathogenic nematodes to control the 2nd instar larvae of Spodoptera frugiperda. The pathogenicity of entomopathogenic nematodes with a high virulence were tested against prepupae and pupae. All isolates, showed infectivity to the 2nd instar S. frugiperda larvae; Steinernema feltiae 0663PG and Steinernema krussei 0657L were particularly effective. After exposing one 2nd instar S. frugiperda larva to 160 S. feltiae 0663PG for 72 h, the mortality rates were 100% for the former. When exposed to 50 S. krussei 0657L, the 2nd instar S. frugiperda larvae had a mortality rate of 80%. The S. frugiperda prepupae pupated successfully after 2 d of being infected with S. feltiae 0663PG. When exposed to 3200 S. feltiae 0663PG for 15 d, S. frugiperda pupae had eclosion rates of 96.67%. However, after exposing one S. frugiperda pupae to 12800 S. feltiae 0663PG for 13 d, S. frugiperda pupa had eclosion rates of 93.33%. The mortality rates of S. frugiperda prepupae and pupae were less than 10%. The results showed that S. feltiae 0663PG has great potential as a biological control for S. frugiperda larvae. The S. frugiperda prepupae and pupae were insensitive to the entomopathogenic nematodes, and infections of the latter had no significant effect (P > 0.05) on the rate and time of the emergence of S. frugiperda pupae.
Turf can positively impact people’s livelihoods and well-being. It can beautify urban environments, maintain water and soil quality, absorb carbon dioxide, purify the air, moderate temperatures, reduce noise, and absorb other plant allergens. It is an inclusive ecological product, an important indicator of the quality of people’s lives, and a symbol of national and urban civilization. The turf industry, which relies on research and development, production, sales, maintenance, and management of turf, is an emerging industry that began to flourish in the world after the Second World War and has matured in Western countries. The turf industry in China started late and has been developing rapidly in tandem with the urbanization process. Compared with other developed countries, a large gap and many shortcomings remain in China. China is in need of a complete turf industry development system to accelerate the green development of a high-quality turf industry. This article first describes the status of China’s developing turf industry, then sorts out opportunities and challenges facing turf industry development. Finally, it proposes turf industry development countermeasures, aiming to provide a reference for promoting regulated, healthy, orderly, and stable development of China’s turf industry.
Grassland circulation is conducive to optimizing the allocation of grassland resources and promoting the large-scale operation of animal husbandry. Empirical analysis of the impact of grassland circulation on herders’ family income is of notable importance with respect to the sustainable development of grassland animal husbandry. On the basis of household survey data obtained for the pastoral areas of Qinghai and Gansu Provinces, China, we used multiple regression models and propensity score matching methods to analyze the impact of grassland circulation on the household income of herdsmen. In addition, we further examined group differences in the effects of grassland circulation on the family income of herdsmen at different grassland scales and income levels. The results obtained revealed the following patterns. 1) Grassland rent-in can contribute to increasing herders’ family income, whereas grassland rent-out has no significant impact on family income. 2) The average treatment effect of grassland rent-in on the per capita annual income of herders’ families was 6576 CNY, and grassland rent-in raises the per capita annual income of herders’ families by 47.25%. However, we failed to detect any significant effect of grassland rent-out on the per capita annual income of herders’ families. 3) Grassland rent-in had a comparably greater impact on the family income of larger-scale and high-income herders. Moreover, we found that herders with low incomes and small grassland areas are unable to obtain higher economic benefits from the grassland circulation market. Consequently, the income gap among herders has widened. On the basis of these findings, it is proposed that local governments should establish a grassland circulation market mechanism and legal guarantee system for the allocation of grassland resources that improve the mechanism for determining rent in grassland circulation, protect the interests of low-income herders in the circulation of grasslands, and enhance the efficiency of grassland circulation.