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Lawn grass with strong tolerance plays a significant role in disposing of heavy metal pollution and repairing copper tailings by phytoremediation. Therefore, perennial ryegrass (Lolium perenne) was used to remediate different proportions of copper tailings and soil using pot experiment. The growth status of perennial ryegrass, physicochemical properties of soil, soil enzymatic activities, content of total Cu and available Cu in soil, and content and distribution in ryegrass were investigated and analyzed. The results showed that perennial ryegrass was capable of growing well in copper tailings without any serious damage. Both the nutritional ingredients and the soil enzymatic activities from the copper tailings were distinctly improved. Compared with the blank group without cultivated plants, the organic matter, total N, total P, and total K of the trial group with ryegrass plantings were increased by 55.5%, 44.1%, 30.0%, and 24.9%, respectively. The activities of invertase, urease, phosphatase, and catalase were increased by 24.8%, 20.5%, 11.4%, and 14.2%, respectively. Differences between the two groups existed(P < 0.01). Additionally, the growth and uptake by the perennial ryegrass accelerated the activation of Cu, which reduced the content of Cu in soil by 12.2% to promote the restoration process of the Cu-contaminated soil. The experimental results illustrated that it is not only possible to restore the field copper tailings by utilizing the perennial ryegrass, but it also offered a reference to recover the heavy metal contaminated tailings by using phytoremediation.
The ecological problems of Sanjiangyuan Region have a very important impact on the national ecology and economy. It is of great significance to study the sustainability of its environmental and socioeconomic development. The study used the ecological footprint model to calculate and analyze the ecological footprint, ecological carrying capacity and ecological surplus of Sanjiangyuan from 2000 to 2012 year. The research results showed that the per capita ecological footprint of Sanjiangyuan was on an upward trend from 2000 to 2012, and the land use types were unevenly distributed. Among the above 6 land use types, the supply rate of crop land was the largest, followed by forest land, water land, grassland, and the supply rate of fossil fuel land and built-up land. Per capita ecological carrying capacity showed a downward trend. The order of decline was 40% for built-up land, 29.95% for grassland, 20% for crop land, 14.81% for woodland, and 2% for water. In addition, the grassland contributed the most to the ecological carrying capacity, with an annual average contribution rate of 41%, followed by 38% for forest land; Sanjiangyuan Region had an overall ecological surplus, but the surplus had a downward trend. There were also differences in the ecological gains and losses of different land types. Among them, grass land and forest land were ecological surpluses, and the crop land and fossil fuel land were ecological deficits. Water land and built-up land began to shift from ecological surpluses to ecological deficits.
Based on alpine meadow in Haiyan, Qinghai Province, we analyzed the effect of fencing and climatic conditions on vegetation characters from 2003 to 2015. The results indicate that: 1) The free grazing grassland aboveground biomass, canopy height were significantly lower than that of fencing land (from May to September) in recent 13 years, and the coverage on June and July significantly lower than that in fencing land. 2) Based on the data which were observed at the end of July in fencing grassland ,we found that canopy height a trend of parabola, and the coverage showed a power function trend; 3) The maximum value of annual aboveground biomass is consistent with the trend of average temperature from June to July, and has a significant power function relationship (P < 0.01), the impact of the precipitation for the remain delay, aboveground biomass and the year precipitation has a significant power function relationship; 4) We used SPSS l Linear regression analysis to build a prediction model for the aboveground biomass, which showed as follow: y = 124.44TJune-July + 2.59Rprevious year – 2 180.23 (P < 0.01).
Grassland ecosystem is susceptible to environmental change, it is of great significance to study the changes of grassland cover and ecosystem service function. Based on the remote sensing data and InVEST model, we taken the Shiyang River basin as the research area in this paper, and quantitatively estimated the service functions of grassland cover change, water yield, soil conservation and carbon sequestration service since 2000, and discussed the effects of grassland cover change on ecosystem service. The research results showed that the degradation of grassland cover in the Shiyang River basin was obvious during 2000–2015; the water yield of grassland was decreased first and then increased, and the service of soil conservation and carbon sequestration were decreased. There was a significant negative correlation between grassland coverage and water yield in the middle reaches of the river basin, and a negative (P < 0.001) correlation with the downstream soil retention while there was a significant (P < 0.001) positive correlation between the grassland coverage and other ecosystem services; the obvious vegetation degradation in the upper reaches of the Shiyang River basin gave rise to the decline of grassland ecosystem service capacity, so improve the quality of grassland ecosystem in the upper reaches have a great significance to advance the ecosystem service of the whole watershed.
For the study of soil carbon cycling, it is important to investigate the effects of hydrothermal factors on soil respiration under different land cover types in arid areas. In this study, soil respiration during the growing season under three land cover types (Haloxylon ammodendron plantation, oasis field, and poplar plantation) was measured in a desert-oasis ecotone in Northwest China. The response of soil respiration to hydrothermal factors under the three land cover types was analyzed. There were differences in monthly soil respiration among the three land cover types. From April to September in 2016, soil respiration was 0.59 μmol·(m2·s)–1 in the H. ammodendron plantation, 2.67 μmol·(m2·s)–1 in the oasis field, and 3.16 μmol·(m2·s)–1 in the poplar plantation. The monthly variation in soil respiration was influenced by both soil temperature and soil moisture. The relationship between soil temperature and soil respiration can be simulated by linear and exponential equations, whereas the relationship between soil moisture and soil respiration was more complex and had a quadratic function. For all three land-cover types, the diurnal variation in soil respiration showed a single-peak curve, which was mainly affected by soil temperature.
Bidens pilosa is a highly destructive invasive plant species in the family Asteraceae. The invasion of B.pilosa has caused enormous losses in agriculture, forestry, and livestock industries. In this study, recent research on the invasion mechanism of B.pilosa was reviewed, including biological characteristics, plant-soil feedbacks, ecological effects of invasion, biological control, phytoremediation, and medicinal value. Research indicates that the fecundity, vagility, and environmental adaptability of this species caused it to rapidly expand after the initial invasion. The aqueous extract, leaf volatiles, and root secretions of B.pilosa can inhibit the germination of other plants’ seeds and cause damage to plants, such as cell rupture and structural variation. B.pilosa can regulate its growth and create a favorable environment through changing the microbial community structure, nitrogen and phosphorus content, and soil enzyme activity in root soil, helping to facilitate invasion. Arbuscular mycorrhizal fungi can also improve the stomatal conductance and root branching status of B.pilosa , thereby improving drought resistance. Parasitic plants or vines can control the spread ofB.pilosa , and spraying chemical pesticides such as metsulfuron-methyl and glyphosate can be used for sterilization and prevention purposes. It is expected that a biological herbicide sourced from other plant allelochemicals will be developed in order to control B.pilosa in the future. Additional research on B.pilosa is important, as this species could potentially be used for medicinal and phytoremediation purposes.
The construction of artificial lakes in different degraded grasslands may improve the ecological environment of adjacent degraded grasslands, positively affect the nutrient flux in degraded grassland soil, and accelerate the restoration of degraded grasslands. In this study, the dynamics of soil nutrients at six different distances (10 m, 60 m, 100 m, 150 m, 250 m, and 600 m) from the artificial lake and differences among three years (2014–2016) were analyzed. The results were as follows: soil moisture and soil nutrients (organic carbon SOC, total nitrogen TN) in different degraded grasslands showed the " near-lake effect” in the short 3-year period after the lake was built, and soil moisture and soil nutrient content near the lake was higher. The soil moisture, organic carbon, and total nitrogen in the upper soil (0–10 cm) were higher than those in the lower soil (10–20 cm), the soil nutrients in the heavily degraded grassland (HG) were lower than those in the lightly degraded grassland (LG). In 2016, the TN at 150 m from the lake was ordered HG (2.03 g·kg–1) < LG (2.78 g·kg–1). The SOC in the HG increased by 10% (10 m), 44% (60 m), 48% (150 m), and 54% (250 m). However, the SOC in the LG only increased at the distance of 10 m from lake with increasing years, being up to 53%. The TN decreased with increasing years and decreased by 11% (HG) and 16% (LG) at 150 m from the lake. The results showed that the artificial lake affected the soil nutrient flow of adjacent degraded grasslands, especially in regard to distance, and exhibited some regularity.
The effects of urbanization on biodiversity is an important field in urban ecology. We investigated plant communities in three green-land types, parks, residential areas, and roads along an urbanization gradient in the Beijing urban area (inner 6th ring road). Species composition, similarity index, and diversity of plants in urban areas were calculated. The results showed 536 species, belonging to 103 families, and 319 genera in the Beijing urban area. Among them, there were 361 native species and 175 imported species. 80 species were imported from abroad and 95 species from inland, namely 14.9% and 17.7% of the total species, respectively. The species richness and diversity of trees and shrubs first increased and then decreased along the urbanization gradients, with the decreasing trend from the inner 2nd ring road and the increasing trend from the 3rd – 4th ring road. No significant difference was found along the urbanization gradient for herbaceous plants. There were no significant differences in species evenness along the urbanization gradient.
Through a field survey of low mountain deserts in the upper reaches of the Manas River in Xinjiang, it was found that there were 294 species of seed plants belonging to 174 genera in 44 families, including one gymnosperm species, 43 angiosperm families, and 173 angiosperm genera, in 293 species. Among the families, there are 38 single-species or oligospecies (2～10 species) families (86.37%), and six larger (21～50 species) and medium-sized families (11～20 species). The number of species is 62.93% of the total, which is the main body of the flora; the dominant families are mainly Compositae, Chenopodiaceae, Cruciferae, Gramineae, and Leguminosae. Among the genera, Salsola and Astragalus, represented only by 11～20 species, are the dominant genera in this area. There are 269 species of 172 genera in two to six species and single genera families, accounting for 98.85% and 91.50% of the total genera and species, respectively, which are the main components of the floristic characteristics. Life style is based on herbs (254 species), containing 139 species (including 66 species of short-lived plants) of herbs from 1～2 years old, followed by 110 species of perennial herbs (including 11 species of short-lived plants). Among them, there are five species of parasitic plants, 26 species of shrubs, 12 species of semi-shrubs, and two species of trees. Ecotypes are dominated by mesophytes (198 species), accounting for 67.35%, but xerophytes are mostly the dominant genera and species in this area. The geographical distribution of the flora in this area is complex, exhibiting eight distributional types and 11 subtypes at the genera level, which mainly corresponded to variants in temperate floral distributions (75 genera, accounting for 51.73%), which have a close relationship with the Mediterranean and West Asia to Central Asia distribution area types and their variants (42 genera, accounting for 28.97%).
In order to study the general and physiological effects of exogenous hormones on the seed germination and root and shoot growth of Caucasian clover (Trifolium ambiguum), two hormones, indole butyric acid (IBA) and 1-naphthaleneacetic acid (NAA), were used to treat the seeds and roots of Caucasian clover plants. The following results were obtained 1) NAA soaking treatment effectively enhanced the germination of Caucasian clover seeds, with a concentration of 10 mg·L–1 having the most significant effect (P < 0.05). The germination rate increased from 37% to 55%, and the germination power increased from 38% to 45%. IBA and NAA soaking also increased the seed vigor index to a level that was more than double that of the control. 2) Both IBA and NAA treatment accelerated the growth of the aerial parts of root buds, with the effect of IBA being more pronounced. 3) Soaking in 2 500 mg·L–1 and 3 000 mg·L–1 NAA increased the accumulation of soluble sugar and starch in plants. In summary, treatment with NAA at a concentration of 10 mg·L–1 is optimal for promoting the germination of Caucasian clover seeds, 2 000 mg·L–1 IBA is the optimal concentration for promoting the rapid growth of the aerial parts of roots, and high concentrations of NAA are more effective for promoting the accumulation of non-structural carbohydrates in the root pods of Caucasian clover plants.
In order to select suitable combinations of herbicides for oat fields, 96% S-metolachlor in combination with 10% bensulfuron methyl and 57% 2,4-D butyl ester with 10% fluoroglycofen were evaluated in different ratios and concentrations for their weed control efficacy, oat yield, and safety. The results showed that there were significant differences among the treatments (P < 0.05). The average control effect of mixed herbicides was higher than that of the single agents: T5 and T9 had the highest weed control efficacy, but the latter injured oat plants. For a safe combination, weed control efficacy, and oat yield improvement, the best combination was 57% 2,4-D butyl ester (438.5 mL·ha–1) and 10% fluoroglycofen (300 mL·ha–1)(T12), which resulted in 87.99% weed control efficacy, 9 875.3 kg·ha–1 oat hay yield, and 4 314.3 kg·ha–1 grain yield.
In order to elucidate the effects of exogenous γ-aminobutyric acid on the high temperature stress tolerance, plant growth, root activity, leaf membrane stability, chlorophyll content, reactive oxygen species metabolism, antioxidant enzyme activities and gene expression, endogenous hormones were investigated in a heat sensitive cultivar ‘Pinnacle’ of perennial ryegrass (Lolium perenne) under high temperatures (35 ℃/30 ℃) in growth chambers for 21 d. The results showed that heat stress decreased plant growth, root activity and chlorophyll content, and increased leaf electrolyte leakage, reactive oxygen species and antioxidant enzyme activities. The inhibiting hormone abscisic acid (ABA) content increased while the growth-promoting hormones auxin (IAA), gibberellin (GA3) and cytokinin (ZR)decreased under high temperature stress. Exogenous application of γ-aminobutyric acid (GABA) remarkably promoted plant growth, increased turf quality, chlorophyll content and root activity under heat stress. In addition, the growth-promoting hormones IAA, GA3 and ZR, and the gene expression levels of antioxidant enzymes and the enzyme activities were also enhanced by GABA application when compared to the non-GABA treatment under high temperature stress. These results suggested that the enhanced high temperature stress tolerance by exogenous application of GABA may contribute to the induced higher antioxidant systems and the growth-promoting hormone IAA, GA3 and ZR levels.
Fertilization has an important effect on the yield and morphology of alfalfa (Medicago sativa), which is a high quality protein forage. This paper has studied the effect of different proportions of P and K on the second batch of yield and morphology structure of alfalfa. The research showed that 1) fertilization with different ratios of P and K can significantly increase the biomass of alfalfa (P < 0.05). When single P fertilizer was applied at 240 kg·ha–1, the yield of the second batch of alfalfa was the highest; the fresh yield was 18 203.33 kg·ha–1, and the hay yield was 3 975.97 kg·ha–1, which were significantly higher than those of the control (88.25% and 78.11%) (P < 0.05). 2) Fertilization with different ratios of P and K had a certain influence on the morphological structure of the second stubble of alfalfa. When P at 80 kg·ha–1 and K at 60 kg·ha–1 was applied, the stem to leaf ratio of alfalfa was the lowest (0.98). There was no significant difference (P > 0.05) between this stem to leaf ratio and that when P at 80 kg·ha–1 and K at 30 kg·ha–1 was applied (1.03). When P at 80 kg·ha–1 and K at 30 kg·ha–1 was applied, the alfalfa plant height, main stem length, and internode length were higher, and showed significant differences from those of the non-fertilization control group (P < 0.05). A single application of P at 160 kg·ha–1 is beneficial to the branch promotion of alfalfa. 3)We utilized a fuzzy logic membership function to comprehensively evaluate the yield and various indices of morphology structure of alfalfa. The treatment of P at 80 kg·ha–1 and K at 30 kg·ha–1 ranked in first place with 0.76 points. Therefore, when planting alfalfa in the karst area of Guizhou, we suggest a treatment of P at 80 kg·ha–1 and K at 30 kg·ha–1.
In this study, changes in the function of PSII (Photosystem II) in the leaves of Deyeuxia angustifolia across a water gradient were analyzed using a chlorophyll fluorescence technique with leaf samples from three typical wetland types from a plain in Sanjiang. The three wetland types were marshes (perennial ponding), marshland meadows (seasonal ponding), and meadows (no ponding on the surface). The results showed that the two indices for the Deyeuxia angustifolia leaves, PSII maximum photochemical efficiency (Fv / Fm) and photosynthetic performance (PIABS) based on the absorption of light energy, increased by varying degrees after a decrease in soil moisture in the marshland meadow and the other meadows when compared to the marshes. This indicates that PSII photochemical activity in the leaves from the marshland meadow and the other meadows was significantly higher than that of the leaves from the marshes. According to the OJIP curves for the Deyeuxia angustifolia leaves that were standardized across the water gradient, we found that OEC (oxygen evolving complex) activity of the PSII donor side and the electron transport capacity of the PSII receptor side were significantly higher in the leaves from the marshland meadows and the other meadows than that of the leaves from the marshes. The actual photochemical efficiency (ФPSⅡ) and electron transport rate (ETR) of the leaves from the marshland meadows and the other meadows with high light intensities were also significantly higher than that of the leaves from the marshes. Furthermore, the study on light energy utilization by Deyeuxia angustifolia leaves across the water gradient revealed that the proportion of light energy absorbed and consumed, in the form of ineffective heat by PSII in the leaves from the marshland meadows and other meadows, was reduced, and the proportion of distribution to the inactivation reaction center while the light energy was being absorbed was used more in the photochemical reaction center to improve the photochemical function in the PSII reaction center. There was no significant difference in PSII function between the leaves from the marshland meadows and the other meadows, which indicates the PSII function of Deyeuxia angustifolia leaves has a strong adaptability across a water gradient.
This study was conducted to determine the effect of a super absorbent polymer on stolon germination and seedling morphological characteristics of Cynodon dactylon and optimum polymer quantity. We used an indoor pot experiment with 5 gradients of super absorbent polymer concentration [0(CK), 0.10%, 0.20%, 0.30%, and 0.40%] under two moisture conditions (adequate water supply and limited water supply) to conduct a comprehensive analysis, as well as an evaluation of drought-resistance of C. dactylon. The results showed that: 1) A suitable concentration of super absorbent polymer can improve germination rate, germination potential, and the germination index of C. dactylon stolons, and the optimal super absorbent polymer concentration under sufficient water supply conditions was 0.30%, 0.20%, and 0.10%, respectively. These values increased by 13.24%, 10.11%, and 20.14% compared with that of the CK, respectively. Optimal super absorbent polymer was 0.30% under limited water supply conditions, and the values increased by 12.67%, 14.87%, and 8.71% compared with that of the CK, respectively; 2) The application of super absorbent polymer improved the biomass and root-shoot ratio of C. dactylon seedlings, whereas when the concentration was 0.20% to 0.30%, the C. dactylon root-shoot ratio was lower than that of the CK. Under sufficient water supply conditions, root-shoot ratio reached the maximum (0.019) at 0.10%, and at 0.40% (0.013) under the limited water condition, the root-shoot ratio was higher than that of the CK; 3) The application of super absorbent polymer could increase the plant height and root length; plant height increased first and then decreased with the increase of super absorbent polymer concentration under the two water conditions. Root length increased with the increase of super absorbent polymer concentration under both conditions and reached the maximum in the 0.40% treatment; 4) Based on membership function analysis, adding a suitable concentration of super absorbent polymer can improve the drought-resistance of C. dactylon seedlings. The order of concentrations for drought resistance of C. dactylon seedlings was 0.20% > 0.30% > 0.40% > 0.10% > 0 under sufficient water supply conditions and was 0.30% > 0.40% > 0.20% > 0.10% > 0 under limited water conditions. Therefore, we suggest the addition of super absorbent polymer at a concentration of 0.20%～0.30% when using C. dactylon for lawn laying and ecological afforestation, which is beneficial to greenland construction and prolongation of lawn irrigation time.
Disease is one of the main limiting factors in pasture production. Many diseases can reduce pasture production and affect pasture quality, leading to plant death in severe cases, but often leading to premature senescence and degradation of the pasture. It can also cause livestock poisoning, and reduce livestock production performance. This article summarizes the effects of diseases, such as downy mildew, rust, powdery mildew, brown spot, and root rot, on the photosynthesis, nutrient composition, and root nodules of leguminous forage, such as alfalfa (Medicago sativa), erect milkvetch (Astragalus adsurgens), and common vetch (Vicia sativa). In general, infection by pathogens can destroy the normal structure of leaves and nodules, reduce photosynthesis and nitrogen fixation capacity of forage, and cause metabolic dysfunction of the plants. Plant metabolic dysfunction and synthesis and release of pathogenic virulence substances also alter plant nutrients. The mechanism of the effects of disease on the physiological growth, nutrient composition, nodule formation, and nitrogen fixation of leguminous herbage was analyzed to provide a reference for research and the prevention and control of leguminous diseases in the future. Furthermore, there are prospects for research in this field combined with the needs of the country's industries, and suggestions are made for future research.
To compare the feeding values of brewing-forage sorghum (Sorghum bicolor) and rain-forage maize (Zea mays) under different planting methods, we studied brewing-forage sorghum planted in an open field and grain-forage maize planted by whole field surface plastic mulching and double ridge-furrowing in Longdong dryland. A feed material yield comparison test and an economic benefit analysis of the two crops were carried out. Additionally, the nutritional composition, feeding value, and net energy were analyzed both at the milk stage of the whole plant and in mature straw. The results showed that the economic benefit of planting brewing-forage sorghum in an open field is higher than that of grain-forage maize planted by whole field surface plastic mulching and double ridge-furrowing. Most indicators of nutritional composition, feed quality, and net energy of brewing-forage sorghum were significantly lower than those of grain-forage maize at the milk stage (P < 0.05). At the mature stage, the opposite results were observed, but the differences were not significant (P > 0.05). The crude protein yield, total digestible nutrients, and dry matter milk net value of brewing-forage sorghum per hectare were higher than those of grain-forage maize, showing extremely significant differences (P < 0.01). The economic benefit and feeding value of brewing-forage sorghum straw planted in an open field were better than those of whole film grain-forage maize at the mature stage. Thus, brewing-forage sorghum should be planted in an open field rather than under whole film double furrow sowing that is used for grain-forage maize in the northwest dry farming area of China.
A field experiment was conducted to investigate the effects of planting density on biomass yield, agronomic characters and nutritional quality. Six silage maize varietieswrer studied to provid a basis for optimizing silage maize production technology based on selecting suitable planting density to obtain high biological yield, good nutritional quality, and the best comprehensive properties of silage maize varieties. The results showed that the biological yield was increased with the increase of planting density, high and medium density had greater biological yield from 8.1% to 43.0% and 5.0% to 19.9%, respectively, than that of low density for the 6 silage maize varieties. In particular, Gansu silage 2 and Hokuno silage 368 demonstrated better resuilts in the increase of biological yield. Harvest day of silage maize was delayed, stem diameter and stay green were decreased with the increase in planting density. Compared to low density, high density increased harvest day by 3.2% to 10.6%, decreased stem diameter and stay green from 6.0% to 22.8% and 2.7% to 3.9%, respectively. The effect of planting density on crude fat was significant, and the crude fat content was decreased with the increase in density. The crude fat content at high density was from 6.8% to 13.5% lower than that of low density. However, the content of neutral detergent fiber and acid detergent fiber was increased with the increase of density, high density had greater neutral detergent fiber and acid detergent fiber by 5.0% to 8.5% and 5.9% to 16.2%, respectively, than that of the low density plantings. Overall, integrated biological yield, agronomic traits, quality traits, the suitable silage maize in the Zhangye area was Gansu silage 2, Wu Ke 107, and Hokuno silage 368. The appropriate planting density for Gansu silage 2 and Hokuno silage 368 was 7.5 × 104 plants·ha–1, and the appropriate planting density of Wu Ke silage 107 was 9 × 104 plants·ha–1.
To investigate the effects of irradiation on Linum usitatissimum seeds, nine varieties of L. usitatissimum were irradiated with different doses of 60Co-γ radiation, and the effects of radiation on seed germination and seedling growth were examined. The results indicated that the effects of radiation on seed germination varied among the different varieties. With the exception of Longya 9 and Longya 10, the seed germination rate of the other seven varieties was negatively correlated with radiation dose, and the germination rate and relative emergence rate decreased with increasing dose. Semi-lethal doses for the L. usitatissimum varieties Longya 14, Longya 13, Dingya 17, Tianya 10, Longya 9, Zhangya 3, Longya 11, Longya 10, and Longya 12 were 6 668, 6 521, 6 462, 6 417, 6 399, 5 869, 5 786, 5 716, and 5 681 Gy, respectively. Lower doses (lower than 1 000 Gy) of radiation increased the germination rate of Longya 9 and Longya 14. At high doses (higher than 12 000 Gy), the rate of germination and seedling growth were markedly inhibited. Although seeds were able to germinate, seedling growth rate was significantly inhibited and the rate was 0. With the exception of Zhangya 3 and Longya 13, the plant height and root length of the other seven varieties increased under low-dose irradiation, and decreased at high dose. The results of this study will provide a theoretical basis for mutation breeding and acceleration of the breeding process of L. usitatissimum.
R1-MYB, a subtribe of the MYB family, may be involved in responses to abiotic stress in plants. In this study, a MYB transcription factor ‘TrMYB1R1’ was cloned from white clover (Trifolium repens) through RT-PCR and RACE. The complete sequence of TrMYB1R1 is 1 403 bp encoding 297 amino acids. Based on the analysis of information biology, TrMYB1R1 contains a MYB structural domain and its conservative domain could form 3 alpha-helixes, indicating that TrMYB1R1 is a MYB-related protein. TrMYB1R1 was located in the nucleus through prediction of the subcellular localization. The result of homologous evolution analysis showed that TrMYB1R1 has closer genetic relationships with MYB of Leguminosae. The TrMYB1R1 could be induced in leaves and roots of white clover under abiotic stress and phytohormone treatments. In detail, the expression of TrMYB1R1 was inhibited under water stress (PEG), cadmium, cold (4 °C), and heat (35 °C) stress. More importantly, cadmium and cold had stronger effects on the expression of TrMYB1R1 than PEG treatment. Differently, salt (NaCl) stress could significantly induce the increase in the expression of TrMYB1R1. For the phytohormone treatments, abscisic acid (ABA) inhibited the expression of TrMYB1R1, whereas cytomin (CTK) induced its expression. All of these results indicated that TrMYB1R1 could be involved in responses to abiotic stress and phytohormones, but the function of TrMYB1R1 still requires further investigation in white clover.
The compensatory growth characteristics of Heteropogon contortus, a common native herb and test material in the dry, hot valley of the Jinsha River, with the addition of water and nutrients and mowing was studied. The dry matter weight of litter decreased after mowing; however, it increased with high-frequency precipitation or when nutrients were added. When nutrients were added, the dry matter weight of crown was higher after the high frequency precipitation treatment. The highest dry matter weight per plant and the weight of its roots, stems, and leaves appeared when there was high frequency precipitation, added nutrients, and when unmowed. The root-shoot ratio of plants with no added nutrients but had mowed crowns was significantly higher when compared to that of the other plants (P < 0.05) regardless of the frequency of precipitation. The reproduction allocations of plants with no added nutrients, mowed crowns, and high and low precipitation frequency (1.2%, 0, respectively) were significantly different (P < 0.05) and lower when compared to that of the other plants. The compensation indices for the biomass of the plants and the roots, stems, leaves, inflorescences, and fruits after mowing were the highest when precipitation frequency was low and when nutrients were added. Furthermore, the growth patterns of the plants and their roots, stems, leaves, inflorescences, and fruits were undercompensated. Therefore, mowing had an adverse effect on the formation process of litter and the accumulation of biomass in the H. contortus meadow; however, the appropriate amount of water and fertilizer can help alleviate this unfavorable effect, although, the under-compensatory growth pattern of the plants cannot be changed.
Clonal plants exhibit different phenotypic responses to habitat heterogeneity. Ca2+ net flux response of root tips to NaCl stress and resultant modification of physiological integration were studied by measuring Ca2+ net fluxes of older and younger ramet root tips of Buchloe dactyloides under different NaCl stress treatments using non-invasive micro-test technique. The results showed that NaCl stress increases outflow of Ca2+ via voltage-dependent calcium pumps in the plasma membrane. Ca2+ net fluxes of root tips were modified by physiological integration of NaCl stress signals between older and younger ramets. Physiological integration was modified by the Ca2+ signal of ramets in response to nutrient heterogeneity.
Non-structural carbohydrates (NSC) play important roles in plant metabolism, regreening, and regrowth. The dynamic changes in NSC in perennial species are good indicators of grazed, mowed, and restored grassland. In this study, we examined the soluble sugar and reducing sugar contents in the shoots, stem bases, and roots of five legume species (Mellissitus ruthenica, Astragalus adsurgens, Oxytropis myriophylla, Vicia amoena, and V. sepium) in Hulunbeier meadow steppe from July 2015 to September 2016. The results showed that the soluble sugar and reducing sugar contents differed in different species and years, with the soluble sugar content in the roots of the five legume species being significantly reduced during extreme drought conditions (P < 0.05). From April through September in 2016, the maximal values of soluble sugars and reducing sugars in the shoots of V. amoena were 1.01%～7.04% and 0.54%～6.73%, respectively, whereas the contents of these sugars in the stem base were highest in V. sepium at 1.12%～10.06% and 0.52%～2.69%, respectively. Soluble sugar content in the roots of O. myriophylla and reducing sugar content in the roots of V. sepium were 1.68%～7.62% and 0.46%～2.98%, respectively, which were higher than those in the other species. Increased storage carbohydrate in plant roots can improve the resistance to grazing. Commencement and termination of livestock grazing should be late June and early September, respectively, in the Hulunbeier meadow steppe. Suitable management practices include reducing stocking rate, deferring grazing, and discontinuing grazing earlier during drought years. In addition, to promote sustainable grassland utilization, hay production should take place in the middle of August.
The musk response is a unique physiological function of the musk deer, which is directly expressed in the secretion and formation of musk. This study aimed to reveal the relationship between the musk secretion start-up time, different physiological stages and age distribution of musk deer in order to elucidate the mechanism of musk, explore factors influencing musk yield and quality, and provide scientific feeding and breeding management techniques for musk deer. Genealogical records were collected for 50 musk deer from six age groups (1-, 2-, 4-, 5-, 7- and 9-year-old). Observations of feeding intake, behavior, defecation frequency, texture, color and smell of pellets were used to classify the entire musk period into three stages. Complete data for 39 musk deer were recorded. All data were analyzed using Excel 2003 and SAS 9.0 software. Two peaks in the age group were dominated by the adult (> 2-year-old ) and bred group (≤ 2-year-old). The start-up time of the adult group was earlier than that of the bred group (approximately 15 days), and the whole physiological period lasted longer and the change was relatively flat. Younger the musk deer, later the start up time of musk secretion; However, the musk physiological period was more concentrated. The duration of every physiological stage in the 6 age groups was not significantly different, and the duration of variation was bigger. A T-test of non-paired samples was carried out to compare the differences in 3 stages between the adult and bred group. The prime musk-secreting stage was not significantly different (T = –0.68, P = 0.499 2). The vigorous musk secreting stage of the bred group (2.89 d, n = 18) and adult group (4.10 d, n = 21) was significantly different (T = –2.59, P = 0.013 5), whilst the later musk secreting stage was not significantly different (T = –0.26, P = 0.799 7). The total musk physiological period of the bred group (8.67 d, n = 18) and adult group (10.24 d, n = 21) was significantly different (T = –2.05, P = 0.047 0). These results show that the time of vigorous musk secreting stage, total time and musk yield, and quality need to be further explored. The results of this study can lay the foundation for scientific feeding and breeding management techniques and clarify the relationship between the duration of different physiological stages of the musk-secreting period and the yield and quality of musk.
This experiment was conducted to investigate the effect of different bran contents and lactic acid bacteria concentrations on silage quality and nutrient content of a tea residue. Four different concentrations of lactic acid bacteria in a preparation (0, 50, 100, and 200 mg·kg–1) were added to five tea residue materials with different bran contents (0, 5%, 10%, 15%, and 20%). Silage quality and nutrient content were measured after 45 days. The results showed that compared with tea residue silage alone, adding bran increased ammonia/total nitrogen ratio, and contents of lactic acid, acetic acid, dry matter, and ash significantly (P < 0.05), and reduced pH, concentration of crude protein, acid detergent fiber, and tea tannin of silage tea residue significantly (P < 0.05). Adding the lactic acid bacteria preparation reduced pH, ammonia/total nitrogen ratio, and contents of acetic acid, dry matter, and acid detergent fiber significantly (P < 0.05), and increased the contents of lactic acid, crude protein, crude ash, and tea tannin of silage tea residue significantly (P < 0.05). Among them, pH of the silage tea residue with 15% and 20% bran was significantly lower than that of other groups (P < 0.05); the ammonia/total nitrogen ratio and acetic acid content of tea residue with 100 mg·kg–1 lactic acid bacteria were significantly lower than those of other groups (P < 0.05), and the ash content was significantly higher than those of other groups (P < 0.05). In summary, addition of bran and a lactic acid bacteria preparation to the tea residue improved the palatability, silage quality, and nutrient content of the silage tea residue significantly; in terms of silage quality, 100 mg·kg–1 lactic acid bacteria preparation added to the mixture of 85% tea residue +15% bran resulted in better quality of silage tea residue feed.
A bacteria which could convert linoleic acid to conjugated linoleie acid (CLA), was screened from the silage in Qinghai Province. The bacteria was identified by morphological observation and 16S rDNA gene sequence analysis. The bacteria was inoculated to the whole plant corn and was cultured 40 days in seal silage bags. The effects of bacteria on the organoleptic properties and chemical compositions of the whole corn silages were assessed. The results showed that this bacteria strain producing CLA was Lactobacillus plantarum and named ANCLA2. It can effectively improve the content of lactic acid and acetic acid in silage, reduce pH and inhibit the ammonia nitrogen (NH3-N) content, but the dry matter (DM) content of whole plant corn and the crude protein (CP) significantly decreased, and the more the dry matter was lost with the inoculation increasing; neutral detergent fiber (NDF) and acid detergent fiber (ADF) were significantly higher than the control group (P < 0.05), crude fat (EE) and CLA content higher than other treatment groups (P < 0.05). In summary, ANCLA2 bacteria not only ensure the effect of the whole plant corn silage, but also improve the content of crude fat and CLA.
The study was designed to explore the effect of Lactobacillus brevis on the silage quality of different varieties of maize during aerobic exposure. In this study, two maize (Zea mays) varieties, Xianyu 335 and Aoyu 5102, were selected; L. brevis (1 × 105 cfu g–1) was added to each species as a treatment group, and the same amount of distilled water was used as the control group to make the whole plant corn silage. The silage was opened 120 days later, and the fermentation quality and nutritional quality were sampled on 0, 1, 3, 5, and 7 days after opening. As the number of aerobic exposure days increased, the pH value and ammonia nitrogen/total nitrogen (AN/TN) increased gradually, lactic acid (LA) content decreased gradually, neutral detergent fiber (NDF) content increased gradually, and starch content decreased gradually. On day 0 after aerobic exposure, the LA content in the Xianyu 335 treatment group was significantly higher than that in the control group, and the AN/TN was significantly lower than that in the control group (P < 0.05). On day 3, the pH of the Xianyu 335 and Aoyu 5102 treatment groups was significantly lower than that of the control group (P < 0.05). The starch content on days 0, 1, and 3 was significantly higher in the Xianyu 335 treatment group than in the control group, and the NDF content at each period of aerobic exposure was lower than that in the control group (P < 0.05). In summary, the addition of L. brevis can improve the fermentation and nutritional quality of Xianyu 335 and Aoyu 5102 during aerobic exposure.
Alfalfa is considered the " king of forage crops”, as it is the forage legume with the largest cultivation area. Alfalfa contains many secondary metabolites, including a high content of saponins, which are a widely distributed bioactive substance. Saponins can act as antioxidants to enhance the immune response of animals. They also have a great number of benefits to humans, including lowering cholesterol levels and regulating the lipid metabolism. Due to the global research progress in recent years, the physical properties, chemical properties, distribution, content, separation, and extraction of alfalfa saponins are better understood. The prospect of its application is widely anticipated, however further research is still required to provide important information. Additionally, it is pointed out that alfalfa saponin as a green plant additive will be of great development and utilization value, which will also provide important information for the further study of alfalfa saponin.