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In order to reveal the climate change characteristics in Anding District, Dingxi in Gansu under the background of global warming, the climate changing characteristics over the last 41 years (from 1970 to 2010) in this area were analyzed by means of linear regression and moving average with the temperature and precipitation data from Anding District meteorological stations. Mann-Kendall test was also employed to identify the mutation point and inter-annual variability tendency in temperature and precipitation. In the recent 41 years, annual temperature in Anding District significantly increased(P0.05)and the increase rates were significantly higher (P0.05) than that of national average. The mutation tests showed that the annual mutation points of temperature was 1997. The annual precipitation decreased without significance and did not have a mutation point. All of these results revealed that the climate of Anding District was becoming warmer and drier.
Using the wavelet analysis method with Mexican Hat Function, the characteristics of summer precipitation in Xilinhot from 1961 to 2010 was analyzed. The results showed that the cycle of summer precipitation varied with timescales which supported by weak oscillation with larger timescale and volatile oscillation with smaller timescale. The first, second, third and fourth main period of summer precipitation periodic oscillation was 30, 27, 24 and 21 years, respectively. The summer precipitation and periodic changes had an impact on annual precipitation. For the summer precipitation, the cycle was 7 to 15 year for the timescale with more than 30 years, the cycle was 10 years for a 15 year timescale and the cycle was 2 to 9 years for a 9 year timescale. For the timescale with less than 3 years, the periodic oscillation significantly strengthened, the cycle was shorter and unstable, and the precipitation was obviously uncertain. The precipitation was the key factor to determine the grassland vegetation growth status and nutrient accumulation and content.
Based on the daily maximum and minimum temperature data from 6 meteorological stations in Northern Tibet from 1961 to 2010, the temporal and spatial variation characteristics of extreme temperature events at grass growing season were analyzed using the ten indices of extreme temperature. The methods of a 10-year smoothing average, linear regression, correlation analysis, and a Mann-Kendall model test were employed to reveal the rate of change, statistical significance of the trends, and mutation points of extreme temperature indices. The analysis showed that maximum value of daily maximum temperature (TXx), minimum value of daily maximum temperature (TXn), minimum value of daily minimum temperature (TNn) and maximum value of daily minimum temperature (TNx) significantly increased at grass growing season during recent 50 years with the maximum TNn increasing rate at 0.40 ℃·10 a-1. Diurnal temperature range (DTR) significantly decreased at a rate of -0.17 ℃·10 a-1 whereas the length of growing season (GSL) significantly increased with a rate of 1.81 d·10 a-1. The numbers of warm days (TX90p) and warm nights (TN90p) significantly increased with a rate of 4.11 and 11.81 d·10 a-1, respectively(P0.01). Furthermore, the number of TN90p significantly increased with a rate of 23.03 d·10 a-1 during 1981-2010. The numbers of cool days (TX10p) and cold nights (TN10p) significantly decreased with a rate of -3.33 and -6.69 d·10 a-1, respectively(P0.01). In terms of decadal variations, the warm indices (TNx, TX90p,TN90p and GSL) increased while the cold indices(TX10p and TN10p)and DTR decreased. It was also found that the mutation of the TXx was in 1984, the other extreme temperature indices (TNn, TNx, TX10p, TN90p, TN10p, DTR and GSL) occurred after the 1900s, but no mutation occurred for TXn and TX90p. Extreme temperature indices suggested that the climate change was beneficial for grass growing in Northern Tibet.
The plant community characteristics and soil environment of shrub meadow in Daofu which suffered fire were investigated in September 2011. The results showed that fire had significant negative effects on alpine meadow plant community (P0.05). The coverage, height, number, base circumference and biomass of shrub significantly decreased (P0.05). The coverage, height and biomass of herbaceous plant community also significantly decreased (P0.05). There were significant inhibition effects (P0.05) on the growth of aboveground plant community. However, fire increased alpine meadow herbaceous plant community richness and diversity. In addition, fire was beneficial to the root growth of herbaceous plant. Soil microbial biomass carbon and nitrogen, soil bulk density and available phosphorus in 10-20 cm layer significantly increased (P0.05), while the soil pH and total potassium significantly decreased (P0.05).
The appropriate amount of inorganic anions in soil could promote the growth of plant, while the excess amount of anions could lead to soil salinization. The research about the spatial variation characteristics of inorganic anions in soil was of great significance to salinization control and ecological restoration. The present research analyzed the contents of the chloride (Cl-), nitrate (NO3-) and sulfate (SO42-) by ion chromatography in soil of Phragmites communis from sampling sites in Northeast China of 12, from June to October in 2011. The results showed that the average contents of chloride, nitrate and sulfate were 292.67, 297.14 and 367.49 mg·kg-1, respectively. The space distribution of the total content of the three tested anions was affected by seawater intrusion, physi-chemical property of soil and hydrothermal conditions. Dandong and Panjin where soil affected by seawater intrusion had higher contents of anions in soil compared with Daqing which heavier soil salinization. The distribution of the total content of the three anions from June to October was affected by hydrothermal condition and the requirement of P. communis from June to October. The content of anion was the highest in June which decreased from July with the change of hydrothermal conditions and growth period. The content of chloride in soil was influenced by seawater intrusion, degree of soil salinization and human activities. All of Dandong and Panjin in which soil affected by seawater intrusion, Daqing and Changling in which soil salinization was heavier, and Changchun and Nehe in which soil affected by human activities had higher content of chloride in soil. Nitrate content in soil was influenced by hydrothermal conditions and the requirement of P. communis. Mudanjiang, Tongliao, Dandong, Longwan and Nehe which had warmer and wetter hydrothermal conditions had higher nitrate in soil. The space distribution of sulfate content was affected by precipitation. There were higher sulfate contents in soil in the areas with fewer precipitation such as Nehe and Daqing. The transportation of the three anions in P. communis was active.
The vegetation communities and landscape types in Shule River basin were classified and refined based on 231 plant-square survey combined with remote sensing data and existing vegetation data to reveal the characteristics of spatial distribution and other changes of vegetation types with the terrain and other elements. The vegetation landscape heterogeneity was analyzed using the grid line relative frequency from linear sampling method. The results showed that Alhagi sparsifolia, Nitraria tangutorum, Lycium ruthenicum, Tamarix sp., Kalidium foliatum, Sympegma regelii were the main vegetation types in the study area which occupied an absolutely dominant position. These vegetation characteristics of staggered distribution and mutual influence were the important factors influencing the structure, function and dynamics of ecosystems to form unique vegetation communities and landscape system of Shule River. Along with different altitude, the vegetation types were richer and the distribution was more complex with the relative frequency less than 50%. For the different gradient performance of landscape heterogeneity, the relative frequency of dominant populations in different vegetation types were not high and vegetation communities and landscape heterogeneity were lower. Along the vegetation of latitudinal direction, horizontal cross-sectional distribution was single with a large area which had domain population advantages.
By secret plots method, species composition, flora character, living form, growth form, water ecotype and species diversity of harvesting on Pinus tabulaeformis inter forest grassland in Lingkong Mountain were analy. The result indicated that: 1)There is a significant difference between clear cutting and intermediate cutting forest grassland on the geographical composition in the family and species level. The areal types of genera is largely affected by the harvesting time. 2)Therophytes more easily survive in the clear cutting than intermediate cutting forest grassland, cryptophytes may be more suitable growth under the woods environment. 3)The quantity and type of growth and water ecotype are more abundant of clear cutting forest grassland than intermediate cutting. 4)Except Carex lanceolata and Chrysanthemum chanetii, the dominant species in three plots are not the same; Due to the different harvesting time and the degree, species diversity of complex appear: plotⅠ＞plot Ⅲ＞plotⅡ.
Global warming has brought great impacts on the ecological system including extending plants growth period, increasing biomass, increasing photosynthetic rate of the plants with lower optimum temperature without changing stomatal conductance, decreasing the content of sodium, potassium and phosphorus in the leaves. With the temperature increasing, the biomass variations of different types of grassland were inconsistent. Kobresia humilis in alpine meadow would be substitute by other grass and Eymus chinensis would be substitute by Stipa grandis. The insects and rodents were mainly studied with warming which showed that insects increased generations and had a tendency to spread to the high altitude and high latitudes and the rodent increased population density without changing of sex ratio and population age structure. Warming enhanced soil respiration, the activities of soil enzyme and the content of soil bacteria. The present paper summarized the response of each component in grassland ecological system which need further study the influence the grassland ecosystem and biosphere.
In the present study,the physiological and biochemical indicators of two salt-tolerant transgenic lines (b32 and b77) and the wild type alfalfa were compared after 15 days treated with 200 mmol·L-1NaCl, including soluble sugar content, the activities of catalase (CAT),peroxidase (POD) and superoxide dismutase (SOD), photosynthetic rate (Pn) and the content of K+ and Na+. Compared with the wild type plants, the soluble sugar content of the two transgenic lines increased by 48.8% and 39.6%, respectively, the SOD activities increased by 71% and 89 %, CAT activities increased by 21% in b32 and 13% in b77, POD activities increased by 32.9% and 34.1%, Na+ contents decreased by 57% and 44% and K+ contents increased by 23% and 13%, respectively. The photosynthetic rate of transgenic plants increased by 2.4 times compared with the wild type plants. This study demonstrated that the transgenic alfalfa (b32 and b77) had a greater tolerance of saline stress compared with non-transgenic plants.
A type Ⅱ metallothionein gene (SgMT) gene was isolated from Suaeda glauca which had 234 bp open reading frame and encoded 78 amino acids. SgMT was highly expressed in seeds and leaves which were tested by qRT-PCR. SgMT genes up-regulated under different concentrations of Na2CO3 and NaHCO3 salt stress and did not change under high pH conditions. The recombinant yeast cells with SgMT grew better than control cells under 12 mmol·L-1 Na2CO3 and 26 mmol·L-1 NaHCO3 salt stress and had no difference under different pH value. These results suggested that SgMT gene played an important role in plant adaptation to environmental stresses.
The effects of two K+ levels(0.01 and 2.5 mmolL-1)on the growth,ion absorption and distribution of Apocynum venetum under NaCl stress were investigated by the pot experiment. The results indicated that the biomass and plant height of A. venetum decreased with the increase of external NaCl concentration, however, there was no significant difference between 0.01 and 2.5 mmolL-1 K+ under the same salt treatment(P0.05). Na+ contents in all tissues of A. venetum increased significantly (P0.05) with the increase of external NaCl concentration and the increase rate in leaf was greater than that in root and stem. In contrast to Na+,K+ contents decreased significantly but still maintained at a high level in leaf and stem and maintained stable in root with the increase of external NaCl concentration. Furthermore, compared with the control, K+ contents in leaf did not significantly change when A. venetum was exposed to 50 mmolL-1 NaCl. Moreover,A. venetum accumulated high contents of K+ in the absence of salt stress, especially in leaf where K+ contents were 15 times higher than that of Na+. In conclusion, enhancing the capacity of selective absorption and transport for K+, and hence maintaining high K+ contents and K+/Na+ ratio in leaf are the key adaptive mechanisms of salt-tolerance in A. venetum.
In order to find out the most effective seed soaking methods for bluegrass (Poa pratensis), the present research assessed the effects of 30 seed presoaking treatments included 10 seed presoaking agents which combined with three soaking time (1 ,2 ,3 d) on seed germination and seedling growth. The 6 treatments of 2.0% Ca(NO3)2 and 2.0%KNO3 soaking 1, 2 and 3 d significantly improved (P0.05) seeds germination without significant damage to seedling growth, especially for the two treatments of 2.0%Ca(NO3)2 soaking 2 d and 2.0% KNO3 soaking 2 d which were recommended for bluegrass seed soaking treatments. The eight treatments of 2.0% NaCl soaking 1 d, 2.0% CaCl2 soaking 1, 2 and 3 d, 2.0% KH2PO4 soaking 2 d and 0.5 mmol·L-1 SA soaking 1, 2 and 3 d improved seed germination rate whereas they had negative effects on seed mean germination period and seedling growth. The treatments of H2O soaking 1, 2 and 3 d, 20% PEG-6000 soaking 1, 2 and 3 d, 2.0% NaCl soaking 2 and 3 d, 2.0% KH2PO4 soaking 1 and 3 d, 0.3% H2O2 soaking 1, 2 and 3 d, 0.01% KMnO4 soaking 1, 2 and 3 d had negative effects on seedling growth which were not recommended for bluegrass seed priming methods.
In order to investigate the allelopathy of aqueous extracts from rhizosphere soil of Achnatherum inebrians on the seed germination of forages, the influence of aqueous extract of rhizosphere soil from autumn A. inebrians in 0-5, 5-10, 10-15, 15-20 cm layer with the concentrations of 2, 1, 0.2, 0.1 g·mL-1 on the seed germination of Bromus inermis, Medicago sativa, Onobrychis viciaefolia were studied through the standard germination test. The result showed that effects of aqueous extract of rhizosphere soil on the germination rate, germination potential, germination index, radicle length, shoot length, root to shoot weight of three pasture seed were not consistent. Based on the index of comprehensive allelopathic effects, the intensity of restriction to germination of three forages were in the order of M. sativaB. inermisO. viciaefolia. The aqueous extracts had no inhibition on B. inermis and O. viciaefolia seed germination whereas they had some inhibition on M. sativa seed germination which increased with the increase of extract concentration. The aqueous extract in 5-10, 10-15 and 15-20 cm layer from each layer promoted seed germination of B. inermis, O. viciaefolia whereas they had inhibition on M. sativa seed germination which had significant inhibition (P0.05). The aqueous extract of rhizosphere soil from A. inebrians with 0.2 g·mL-1 concentrations had significantly promoted(P0.05) the seed germination of B. inermis and O. viciaefolia. The allelopathy of other aqueous extracts concentrations did not perform consistently which decreased with the concentrations increasing.
Effects of ethephon and salicylic acid (SA) on growth and ergot alkaloids concentrations of drunken horse grass (Achnatherum inebrians) over a 3-week period were determined in controlled experiments in the greenhouse. The variations of the alkaloid contents with ethephon and SA treatment were measured. The results showed that plant heights and above-ground biomass of A. inebrians increased (P0.05) compared with the control (CK) . However, the contents of ergine and ergonovine were higher than that of control (CK) treatment, especially for ethephon treatment which had significant effects (P0.05).
The photosynthetic diurnal change characteristics of Chenopodium glaucum and Myosoton aquaticum were studied in sunny days in karst rocky desertification areas of Guizhou Province with Britain Lcpro+photosynthetic apparatus. The daily mean values of net photosynthetic rate (Pn) of C. glaucum and M. aquaticum were 9.06 and 4.25 μmol CO2·m-2·s-1, respectively. The transpiration rates (Tr) and the water use efficiency (WUE) of these two plants were 3.47 and 3.23 mmol H2O·m-2·s-1 and 2.06 and 1.23 μmol CO2·mmol-1, respectively. C. glaucum had high Pn, Tr and WUE whereas M. aquaticum had low Pn, Tr and WUE which suggested that C. glaucum was more suitable for karst rocky desertification areas with drought and shortage of water.
The agronomy and quality traits of nineteen introduced biennial Melilotus accessions were preliminarily evaluated in Yuzhong, Gansu Province. The results showed that the introduced accessions always performed better and plant height, air dry weight, acid detergent lignin and coumarin content have great variations. The plant height of overseas Melilotus accessions were significantly higher (P0.05) than that of the domestic accessions (LX05 and LX03), and air dry weight of over 75% of accessions were significantly higher (P0.05) than that of the domestic accessions. The coefficient variation (CV) of coumarin content was the greatest among all traits (49.12%). The plant height had significantly positive correlations with air dry weight (P0.05). The ratio of leaf to stem had significantly positive correlations with crude protein (P0.05) whereas it had significantly negative correlations with neutral detergent fiber(P0.05) and acid neutral detergent (P0.01). Through principal component analysis (PCA) with nine character indices, five principal components were fiber factor, biomass factor, plant height factor, quality factor and coumarin factor. Nineteen Melilotus accessions were divided into five groups through the cluster analysis and group Ⅱ was the best. PI552553, Ames25658, PI593233, PI595388 and PI595393 were selected as the better performance accessions with higher biomass, lower coumarin content and higher crude protein.
In order to improve the water and fertilizer utilisation efficiency of Bromus inermis, the influences of irrigation, quantity of nitrogen, phosphorus and potassium fertilizer on quality of B. inermis in Kerqin sandy land were analyzed using orthogonal design method. The results showed that the quantity of nitrogen fertilizer had very significantly effects (P0.01) on the dry biomass and crude fiber content and had significant effects (P0.05) on the crude fat content and ash content. The irrigation had very significantly effects (P0.01) on the dry biomass and crude fiber content and did not have significant effects on the crude fat content and ash content. Both phosphorus fertilizer and potassium fertilizer had significantly effects (P0.05) on the dry biomass and crude fiber content and did not have significant effects on the crude fat content and ash content. The independent effects of four factors on quality was nitrogen fertilizerirrigation quantityphosphorus fertilizerpotassium fertilizer. The multiple indices comprehensive analysis revealed that the optimum treatment to improve B. inermis quality was the combination of 450 kg·ha-1 nitrogen fertilizer, 1 000 m3·ha-1 irrigation quantity, 200 kg·ha-1 phosphorus fertilizer and 75 kg·ha-1 potassium.
The natural grassland vegetations of Shaertao Mountain were abundant which reserved rich forage resources, especially the gramineous which occupied the important position and provided the diet for grazing animals. In the present study, the growth characteristics and palatability characteristics of nine gramineous grasses which were dominant in natural grassland vegetations of Shaertao Mountain were measured and the nutritional values were evaluated by the grey correlation analysis method. The result showed that nine dominant gramineous grass were divided into three water ecological types (xerophyte, xero-mesophyte and mesophyte), four tillering types (dense cluster type, rhizomatous, rhizomes-laxifruticose, laxifruticose), three palatability levels(specially favorite to eat, favorite to eat, wanted to eat). Nine dominant gramineous grass nutritive value of the order was Dactylis glomerataElymus nutansRoegneria sinkiangensisElymus cylindricusPoa angustifoliaBrachypodium pinnatumPhleum pratenseStipa capillataAchnatherum splendens.
The grassland rodents obtain their nutrients for growth and development by eating plant tissues. Therefore, the nutrient contents of plant and its quantity have profound influence on rodents. Variations of nutrient contents have unfavorable effects on rodents which required balanced nutritional conditions for their normal survival and reproduction. The research topic about the effects of plant nutrient contents on rodent had been paid more and more attentions. In the present paper, the effects of plant protein, fat cellulose, mineral substance and vitamin on herbivorous rodents were reviewed to provide reference for related researches.
In order to assess the quality of talent training and graduation practice for undergraduates, the evaluation system of graduation practice for pratacultural science was established based on fuzzy comprehensive evaluation method. The multi-level evaluation system included 5 primary indices and 42 secondary indices. The weights of primary and second indices and the evaluation levels were determined by the academic committee of graduation practice and the literature information committee. The system of fuzzy comprehensive evaluation systematically, qualitatively and quantitatively evaluated the graduation practice of pratacultural science. The evaluation system improved the training mode of tutor system for undergraduate graduation.
The main toxic swainsonine(SW) contents of Oxytropis ochrocephala in various plant parts at different stages were detected by gas chromatography (GC),the dynamic regulation of swainsonine was analyzed, the SW production of the whole grass aboveground part in O. ochrocephala per square metre was investigated and calculated.The results showed that the SW content of fruits was the highest, which was up to 107.787 mg·kg-1, the SW content in aboveground part at fruiting stage was the highest,which was up to 48.19 mg·kg-1. The averages of SW contents in different tissues at 4 period were podsflowersleavesstemsroot,the SW contents in aboveground part and the SW production of the whole grass aboveground part at four growth period were different which decreased in the following order: fruiting periodflorescence periodwithering periodbud formation period.
The five northwestern provinces and municipalities including Shaanxi, Gansu, Qinghai, Ningxia and Xinjiang have large areas of grassland which have great impacts on grassland development in China. In order to enhance the protection and rational utilization of grassland resources, grassland construction and utilization were analyzed using the K-means Cluster which was multivariate statistic method based on the relevant data in China Statistical Yearbook 2013. The seven indices including the utilized ratio of grassland area, the accumulated grassland reserved area ratio, the newly increased grassland area ratio this year, the rodent damage area ratio in grassland, the rodent management area ratio in grassland, the pest damage area ratio in grassland and the pest management area ratio in grassland were calculated. The results indicated that the rodent damage area ratio in grassland, the rodent harnessed area ratio in grassland and the pest damage areas ratio in grassland showed significance among all seven influencing factors(P0.05), meanwhile, the significance of the rodent harnessed area ratio in grassland was the highest among these three significant influencing factors. However, the pest harnessed area ratio in grassland was not significant(P0.05). The results suggested that rodent control had achieved stage results, but the long-term management still need to be strengthened. The effective pest control was urgent and has become a top priority.
The present research analyzed and evaluated Minjiang river basin’s sustainability using a three-phrase SE-DEA model based on ecological environment’s input and output combined with the improved sustainable development indices system. Over the past ten years (2003-2012), the sustainable development of Minjiang river basin’s ecological condition increased in waves and sustainability was still weak. The present research also put forward the main factors which had strong impacts on the ecological environment’s sustainable development, including service sector, science and technology, urbanization, industry and labor. Firstly, the excessive investment was the main factor lead to Minjiang river basin’s environment degradation and resources waste. Secondly, urbanization, innovation of science and technology and the qualified labor can promote ecological environment’s sustainable development. Lastly, industries upgrade and ecological industry development were effective way for ecological environment’s sustainable development.
Grassland is the main vegetation type of terrestrial ecosystems, which is an important ecological protective barrier in China. The physical environment (water environment, soil environment, atmospheric environment and other organisms), structure (population, community, landscape) and function (production function, ecological function) of grassland ecosystem are changing under the circumstances of climatic changes. The present paper described the evaluation indices, methods and effects of climatic changes in details, which could provide reference for related researches.