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Infrared heater was used to simulate temperature enhancement in the field focusing on the effects of temperature enhancement on the growth and photosynthetic characteristics of three alpine plants: Polygonum viviparum, Saussurea superb, and Carex atrofusca in order to provide basis for estimating the sensitivity and friability of the meadow ecosystem in the permafrost region on the Qinghai-Tibet Plateau, China. The results showed that the simulated warming W1 (1.88 ℃) and W2 (3.19 ℃) could all alter the distributing frequency and season pattern of the alpine plant species. Compared with the CK, the W1 temperature enhancement brought different changes to different plants under which the height, frequency and chlorophyll contents of the S. pulchra were decreased but the values of the P. viviparum and C. atrofusca were increased. The W2 warming evidently increased the height, frequency, and chlorophyll content of the P. viviparum and C. atrofusca but significantly (P<0.05) decreased the ratio of chlorophyll a to b of the S. pulchra resulted in its decreases in the height, frequency, and chlorophyll content. It showed significant differences in the photosynthesis indicators among the plant species, especially among the plots. All above indicates that the warming can improve the growth and development of the grazing plants in the alpine meadow and prolong their green grass duration resulting in benefit to the livestock production but the vegetation distribution evidently variegated.
Effects of environmental factors on the growth of endophytic diazotroph strains 7D and BM13 isolated from Cynodon dactylon were investigated in our experiment. In this study, strains 7D and BM13 were examined for their adaptability to the stress of temperature, pH, NaCl, N4+, NO3- and carbon sources by Ashby media. The results showed that the two strains could grow under wide range of temperature of 10~40 ℃ and pH from 3.92~9.64. The strains could also tolerate NaCl concentrations of 30 g·L-1, N4+,and NO3- concentrations of 0~10 mmol·L-1, respectively. The strains were capable of using various carbon sources. It was suggested that the strains 7D and BM13 had superior tolerance to stress of diverse environment factors, but their tolerance abilities differed partly. Endophytic diazotroph strain is a candidate to be further developed for microbial fertilizer production.
In the study, five species of natural herbs in the desertified grassland of northwest Sichuan, including Carex praeclara, Leymus secalinus, Orobanche coerulescens, Carum carvi and Astragalus bhotanensis, were selected to determine their adaptation strategies and mechanisms to desertification habitat by measuring apparent traits, water content, biomass and its allocation ratio, and analyzing the response of growth and development and resource allocation of different herbs to desertified habitats. The results of this study showed that apparent traits were extremely significant difference among five species of herbs(P<0.01), in which O. coerulescens and C. carvi adapted to desertification habitats by encouraging the sexual reproduction, however C. praeclara, L. secalinus and A. bhotanensis adapted to desertification habitats through crowns, rhizomes, and deep roots, respectively. Water content and its allocation proportion also were extremely significant difference among five species of herbs(P<0.01), in which the water content of C. praeclara, L. secalinus and A. bhotanensis preferentially assigned to reproductive branches, but O. coerulescens had priority to stems and leaves, and C. carvi used the water allocation with relative balance. Biomass and its allocation proportion showed aextremely significant difference among five species(P<0.01), indicating that the biomass of C. praeclara, L. secalinus, O. coerulescens and A. bhotanensis preferentially allocated to rhizomes, stems and leave, reproductive branches, and roots, respectively; however, C. carvi allocated the biomass to each component with relative balance. These suggested that five species of psammophytesshowed a difference strategies to trade off resource allocation and they obtained or allocated the limited available resources to increase the adaptability to habitat through varieties of phenotypic plasticity, water using ability and biomass allocation, etc.
Due to human activities and the effects of natural factors such as environmental changes, ecological environmental regulation and self-recovery capability in Qinghai Lake basin, the ecological security problem was become seriously. Using MODIS NDVI product, meteorological data of four counties in Qinghai Lake basin and social data in 2010, this study built a “pressure-state-response (PSR)” model to evaluate the effect of the ecological environment protection of Qinghai Lake basin between 2002 and 2010. On this basis, this study extracted 11 natural resources and social resources data in Qinghai Lake basin to analyze the composite index by the analytic hierarchy process. The main conclusions are as follows. The ecological environment protection of Qinghai Lake basin was in serious condition, vegetation degradation area was more than 2 times of vegetation restoration area between 2002 and 2010. After the implementation of environmental engineering from 2008 to 2010, the situation was on the turn and the deterioration area reduced to the same as the vegetation restoration area. The ecological environment of Qinghai Lake basin had improved, but the regional ecological environment was still in degradation, or even worsen. The 3 415.36 km2 area of Tianjun County was in alert status. The 2 324.57 km2 area of Gonghe County was in alert status. They occupied a land area of 25% and 38%, respectively. More serious situation was found in Haiyan County, where 284.98 km2 area region was in severe danger of ecological security and occupying a land area of 18%, the rest was in a state of mild risk. Finally, according to the results of evaluation, we put forward some suggestions to slow the progress of the ecological environment deterioration and improve the environmental governance planning advice.
Because the low grassland coverage in the arid region causes the weak spectral information, grassland coverage retrieval becomes quite difficult. Comparing four remote sensing retrieval models, we found that the pixel dichotomy model can generally retrieve grassland coverage with higher accuracy. We further produced time-series (2000-2013) of grassland coverage based on the pixel dichotomy model and analyzed grassland conditions over Xinjiang and five countries of Central Asia. Results showed that grassland coverage showed large spatial heterogeneity in the study area. Grassland generally showed degradation trends, especially in the northern and western regions and some basins of Kazakhstan. Grasslands with medium, medium-high, and high grassland coverage were converted into the grasslands with low and medium-low grassland coverage. Grasslands in Kazakhstan degenerated significantly, while the average value of grassland coverage in Xinjiang was significant growth steady.
To find the rational use of water resources for wheat growth periods, this study used the APSIM model to simulate wheat yield under different growth periods with changeable rainfall and estimate the threshold value for requirement of wheat for water at different growth periods. This study showed that the regional precipitation pattern generally showed an alternation from droughts to floods, and the requirement of wheat for water during whole growth periods was 325.3 mm, in which the requirements of wheat for water during emergencing, jointing, heading, flag leaf, flowering and grain filling periods were 34.72, 80.6, 67.1, 43.81, 58.67 and 30.4 mm, respectively, and accounting for 10.67%, 27.85%, 20.63%, 13.47%, 18.04% and 9.35% of total precipitation during wheat growth periods. Precipitation deficitwas 70.78%, 48.83%, 46.22%, 40.35%, 75.66%, -121.05% at, jointing, heading, flag leaf, flowering, grain filling period, respectively, which indicated that the key periods of spring wheat for requiring water were emergencing, jointing and flowering period.
In order to explore the natural variation laws of soil moisture in Xilamuren grassland, north Yinshan Mountains, AZ-DT automatic soil moisture monitor was used to monitor the soil moisture of root zonewith long-term period. Soil moisture, in combination with rainfall observation and vegetation survey, was applied to analyze local soil moisture variation characteristics and its impact on vegetation. The results of this study showed rainfall was the only source of soil moisture of the slope soil and was often below 15% due to rare rainfall. However, soil moisture at slope bottom come from runoff resources and rainfall, and was higher than that of slope soil, which led the soil moisture to be saturation condition. Rainfall significantly affected the height, coverage and biomass of plant community in slope soil, however, did not affect on those of plant community in slope bottom. The plant community in slope bottom is low and thin but large number because poor ventilation and salinization of slope bottom soil was not beneficial to plants growth. The soil moisture of the slope and the bottom was higher and the fluctuation was severe in spring season every year due to freezing thawing and snow melting, which was helpful to grassland regreen with enough water supply.
In order to understand the effects of over-seeding on vegetation composition, soil physical and chemical properties, a field experiment was conducted to determine the effect of over-seeding Elymusnutans, Bromusinermis, Festuca sinensis seeds on degraded grassland during the period of 2007 to 2009 in Tianzhu county. The results of this study showed that over-seeding increased the aboveground and belowground biomass and increased the percentage of sedge and gramineain plant community composition. After three years of over-seeding, the soil physical, chemical properties and microbial biomass contenthadbeen obviously improved when compared to control, indicating that soil bulk density at 0―20 cm became low, and that porosity, moisture content, nutrient content and microbial biomass content C & N became higher. These implied that the degraded grassland had been improved by over-seeding.
We studied the effect of different treatments on the emergence in vitro propagation of Alhagi sparsifolia root segment in the southern fringe of the Taklimakan Desert. The purpose of this study was to provide a new A. sparsifolia vegetation restoration technology. We compared the emergence under three-factors (three kinds of root length, three kinds of planting depth and five kinds of irrigation treatments) fully interactive treatments. The results showed that if keeping the other two factors unchanged the emergence rate was reduced with root length increase, the emergence rate achieve the highest at 10 cm root length. The emergence rate increased with planting depth increasing. Emergence rate reached the highest with planting depth of 30 cm. Emergence rate reach the highest under irrigation regime of 10 m3·m-2 and once on July 30. In addition to the interaction between irrigation treatments and planting depth, there were significant differences among all interactive processing among three factors. In conclusion, 10 cm root length, 30 cm planting depth, 10 m3·m-2 (once) irrigation treatment are the optimal planting pattern.
In order to improve the forage quality of Agropyron mongolicum and screen the best chromosome doubling treatment, the seeds of A. mongolicum were treated with different concentrations of Colchicine (0.02%,0.05%,0.08%,0.11%,0.14%+1.5% DMSO) and Trifluralin (1,5,10,15,20 μmol·L-1) and the morphology and chromosome number were identified after treatment. The results showed that the surviving plants after treated were mixoploid of diploid and tetraploid. The treatment with 0.11% colchicine 1.5% DMSO for 20 h had the highest mutation rate of 50% and the survival rate of 40%. The treatment with 1 μmol·L-1 trifluralin for 6 h had significant mutation effect with probability of 38.46%. These results provide theoretical and experimental basis for further screening the chromosome doubling plants of A. mongolicum.
Seven transgenic lines were selected from transgenic Trifolium repens obtained before,including W1-2, W1-3, W4-2, W13-4, W17-1, W28-2 and W33-3, while non-transgenic lines were used as control.Morphological characteristics and permanent wilting rate of plant were determined. Changes of foliage relative water content, electric conductivity and malon-dialdehyde(MDA) were measured under simulated drought stress by PEG. Results showed that: 1)leaf shape,leaf color, leaf mottling and leaf size of some transgenic T. repens lines changed obviously; 2)The drought-resistant capability of W1-3, W28-2 was strong, which had the lower permanent wilting rate and grew normally for long time; 3)With time and drought stress going on, the relative water content of plants decreased in different degree, but W1-3 and W28-2 could still maintain high level. And the relative electric conductivity and malondialdehyde content of plants had increased, but W1-3 had less change. Through comprehensive analysis, it was concluded that the drought resistant abilities of these seven transgenic lines were ranked as W1-3>W33-3>W28-2>W1-2>W13-4>W17-1>W4-2. Transgenic T. repens lines are superior to the control.
Recently, frequent drought and waterlogging due to climate change caused severe yield loss in spring wheat. The research about the effects of water stress after anthesis on starch formation had great importance for cultivation of spring wheat with stable production and high quality. In the present study, two spring wheat varieties Ningchun 4 and Ningchun 47 which were domain varieties in Ningxia province were selected as material. Four different soil moisture treatments including heavy drought, light drought, normal and water logging were performed by manipulating the post-anthesis soil moisture in pots. The results showed that post-anthesis drought significantly increased (P<0.05) the grain starch content during the earlier filling stage and significantly reduced (P<0.05) the amylose and amylopectin content during the mid and late filing stage so that significantly reduced (P<0.05) the total starch content during the late filing stage. The activities of four key enzymes associated with starch formation, AGPP(ADP-glucose pyrophosphorylase), UGPP( UDP-glucose pyrophosphorylase), SBE (starch branching Enzyme)and SSS(soluble starch synthase), varied with a single peak curve. Water stress depressed these four enzyme activities in spring wheat during the mid and late filling stage. The rate of amylose accumulation in the two spring wheat was significant positively correlated with the activity of SSS (P<0.01).
Lolium perenne cv. ‘Bomber’ is widely applied as turf grass species in the garden lawn of north China. In the present study, the physiological characteristics of ‘Bomber’ with different concentrations of PP333 treatments under drought stress in both greenhouse and the field were evaluated to provide reference for solving the practical water shortage problems in turfgrass management. The results revealed that the physiological indices of ‘Bomber’ leaves after PP333 application had no significant difference under short stress period (10 d), while had significant differences under moderate stress period (20 d) and long stress period (30 d). During drought stress, the leaf relative water content (RWC) declined, whereas the relative conductivity, malondialdehyde (MDA) content and free proline content increased and super-oxide dismutase (SOD) activity fluctuantly changed. Based on these comprehensive responses of physiological indices, PP333 application with the concentration of 200 mg·L-1 can improve the drought resistance of L. perenne. Under the same degree of drought stress, the seedling damage in the field was far less than those in the greenhouse, which indicated that the actual drought tolerance of turfgrass was stronger than the experimental results under the greenhouse drought condition.
In order to select ecologically adaptable orchardgrass cultivars (lines) in western Chongqing, the phenophase, growth rate, yield, stem/leaf ratio, agronomic characters, and nutrient components of eight orchardgrass cultivars/lines were tested for two years. The results showed that all orchardgrass cultivars/lines were able to adapt to the natural environment in western Chongqing. 02-116 showed the fastest growth and the highest hay yield. Aldebaran had the lowest stem/leaf ratio and the highest nutrition value. The comprehensive evaluation showed that 02-116 and Aldebaran were better cultivar/lines compared to others, suitable for planting in western Chongqing.
In the present study, Phalaris arundinacca leaves at different position in filling stage were irradiated with ten different built-in light intensity including 0, 50, 100, 200, 500, 800, 1 100, 1 400, 1 700, 2 000μmol·(m2·s)-1. The photosynthetic parameters such as photosynthetic rate, transpiration rate, stomatal conductance, photosynthetic contribution rate and water consumption rates of leaves from first to fourth position were measured to investigate the response of the P. arundinacca leaves at different position to light intensity and its photosynthetic contribution rate. The results showed that P. arundinacca can use more than 50 mol·(m2·s)-1 intensity light for photosynthesis. Leaf photosynthetic parameters were extremly significantly affected by light intensity and leaf position (P<0.01). The net photosynthetic rate, stomatal conductance, intercellular CO2 concentration (Ci) and transpiration rate (Tr) of P. arundinacca leaves at different position had no significant difference with 500~1 700 μmol·(m2·s)-1 illumination, however, there was photoinhibition when the light intensity was greater than 1 400 μmol·(m2·s)-1. Water use efficiency reached the highest with 800~1 400 μmol·(m2·s)-1 illumination. With natural light, the photosynthetic rate and intercellular CO2 concentration per unit leaf area of P. arundinacca leaves at different position had significant difference (P<0.05). The photosynthetic rate, contribution rate and water use efficiency of second and third leaf were higher than those of other leaves. Therefore, the more attention should be paid to maintaining the integrity and health of first to third leaf for field management in order to obtain adequate nutrition for seed development of P. arundinacca.
In order to exploring the relationship among the agronomic characters and yield and quality of Sorghum sudanense populations, three sudangrass populations were studied with the method of grey correlation degree analysis. The results showed that leaf length and stem diameter had significantly positive effect on hay yield of sudangrass, which is the major limitation factor of hay and fresh grass yield; sudangrass cultivar/lines with less tiller and node, but appropriate leaf length, width and stem diameter possesses relatively high quality; In sudangrass breeding process, according to specific breeding objectives for yield or quality, selecting these agronomic traits with stable performance and correlated relationship with high yield and quality, and understanding the primary and secondary relationship, will help provide theoretical base for new cultivar breeding.
The slow growth of alfalfa (Medicago sativa) at seedlings stage results in the rapid growth of weeds, which severely affects the quantity and quality of alfalfa products. Six common herbicides with low toxicity and suitable for legume were selected for further evaluation. The results showed that 90% acetochlor with 2.0 L·hm-2 spraying in the soil after sowing had best effects which reached 93.81% of relative weeds prevention rate and did not affect yield although alfalfa seedlings grew slowly. Different herbicides should be selected according to different weed species when spraying on alfalfa leaves. The application of 40% bentazone with 3.0 L·hm-2 had 97.09% of relative prevention rate of Echinochloa phyllopogon which also had no harms to alfalfa. The application of 15% fluazifop-p-butyl with 1.0 L·hm-2 effectively control Cirsium setosum and Metaplexis japonica which had 93.63% and 100% of relative prevention rate, respectively. Herbicide was not recommended for Chenopodium album, Portulaca oleracea, Abutilon theophrasti which should be prevented manually.
The reasonable rotational grazing start time had important effects on scientific utilization of desert steppe. In the present paper, plant community characteristics and edible forage nutrients of desert steppe in Ningxia with different rotational grazing start times were studied. The results showed that rotational grazing start time had little influence on species composition of desert steppe after two years of grazing. The plant density in grassland with early rotational grazing was higher than that in grassland with late start rotational grazing, however, the coverage and aboveground biomass had opposite performance. With the delay of rotational grazing start time, the important value of Stipa breviflora, Lespedeza potaninii, Leymus secalinus and Conrolulus ammannii increased, whereas that of Cleistogenes squarrosa decreased, Cynanchum komarovii has no significant difference in different start rotational grazing times. The density, coverage and aboveground biomass of above species had different response to rotational grazing start time. Rotational grazing improved plant species diversity. The plant species dominance of late rotational grazing region was lower than that of early rotational grazing region, however, the uniformity and diversity had opposite performance. With the delay of rotational grazing start time, animal feed rate and forage crude protein content gradually decreased and crude fiber content increased. These results suggested that rotational grazing with fixed time and sequence will increase the heterogeneity of grassland vegetation so that the rotational grazing time and sequence should have appropriate adjustments based on vegetation conditions.
Reviews of the ruminant lactic acidosis indicated that accumulation of lactic acids in the rumen may play an important role in inducing ruminal lactic acidosis, while rumen lactic acids accumulation mainly depends on the degree of balance of rumen producing and utilizing bacteria in feeding high concentrate diets. In this paper, advances in lactic acids metabolism associated rumen bacteria (Butyrivibrio fibrisovens, Streptococcus bovis,Lactobacillus, Selenomonus ruminantium and Megasphaera elsdenii) were discussed, prevention strategies of ruminal acidosis were discussed in purpose to provide reference for further research of lactic acids rumen acidosis mechanism.
Grassland is the main composition of the terrestrial ecosystem. China is the second largest country with grassland resources in the world. However, grassland disasters occurred frequently within the last fifty years, which not only affected forage quality and yield, but also had a serious impact on livestock. Livestock, as an important part of the animal production level, is related to the vigor and production efficiency of the whole ecosystem. Currently, grassland agricultural ecosystem has been suffering from the deepest pressure throughout the biosphere. The paper analyzes the causes, distribution area, frequency of occurrence and development trend of four typical disasters in grassland including snow storms, cyclones, biological disasters(including rats, insects)and drought. Then, policy suggestions are recommended after drawing lessons from international grassland disaster strategies in combination with China’s national conditions.
Based on the investigation in 5 counties in Gansu Province, the inputs and outputs, factorial outputs elasticity and marginal outputs of alfalfa (Medicago sativa), wheat(Triticum aestivum) and maize(Zea mays) at household level were analysed and compared. The results showed that alfalfa had the least inputs, maize and alfalfa had the highest and lowest outputs, respectively. At the moment, wheat and maize were in the stage of decreasing returns to scale, on the contrary, alfalfa was in the stage of increasing returns to scale indicating alfalfa industry had potential improvement. All factors marginal production of wheat and maize closed to zero, in contrast, marginal production of alfalfa were far greater than zero, indicating improvement of seed and fertilizer inputs can increase alfalfa production.
To comprehensively evaluate the influence of different ratios of Carex meyeriana and cotton on yarn properties and encourage the C. meyeriana to applicate textile garments, this study used the method of fuzzy and comprehensive evaluation to evaluate the yarn properties of 12/88, 25/75, 37/63, 46/54 ratios of C. meyeriana and cotton by measuring the fracture strength, elongation at break, hairiness, the evenness, knots, slubs, neps. The results of this study showed that the membership degrees of four different blended ratios were 0.370 5, 0.238 6, 0.210 4, and 0.180 5, respectively. indicating that lower C. meyeriana content was beneficial to the yarn’s comprehensive performances, in which the yarn properties of C. meyeriana/cotton 12/88 was the best in the four different blended ratios. The yarn properties of 25/75, 37/63 blended ratios were similar. Different C. meyeriana/cotton blended ratio could be chosen with the different demands. These results provide the basis for C. meyeriana fibers’ application in textile garments.
After having overviewed current organizational situation on vocational and technical education of prataculture in China, Qinghai Vocational and Technical College of Animal Husbandry and Veterinary Medicine (QVTCAV) is the only onecollege with pratacultural major among 100 national demonstrative vocational institutes. The history and achievement of the pratacultural major in QVTCAV has been initially reviewed in the paper. The reform achievements and existing problems involving curriculum system and the talent training modelsin QVTCAV are then analyzed. Strategies for possible reform and further development have been proposed as following: the curriculum and programs of vocational and technical education of Prataculture Science should be derived from the Theory of Four Production Levels of Grassland Agro-Ecosystem; the curriculum and program should be aligned to the system of national vocational qualification and the system of professional position (title); the vocational and technical colleges should collaborate with enterprises to promote the application of technology demonstration; a national authority of vocational and technical education dominated by pratacultural industry should be established. On the whole, the paper aims to provide reference for improving China’s vocational and technical education of prataculture.
Over 30 colleges and universities have Pratacultural Science major for undergraduates in China, more than 1 000 undergraduates get the bachelor degree in Pratacultural Science each year, which makes the employment competition become more intensive. Therefore, a new training pattern to be proceeded with the times and regional characteristics is required. The formulating progress of talent training scheme and the development trend of Pratacultural Science were simply reviewed in the paper. The training targets, requirements and curriculum setting principles of Pratacultural Science in Shenyang Agricultural University were then introduced, and available suggestions for the talent training pattern to adapt to the new era were finally proposed.