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Cynanchum komarovii is one of the main poisonous weed distributed in arid and semi-arid desert steppes of northwest china. In recent years, rapid spreading of C. komarovii has brought serious harm to local animal husbandry and grassland productivity. With field measured spectra of C. komarovii and other psammophyte plants acquired in the typical district of Alxa Left Banner, Inner Mongolia, spectral characteristics of leaf, canopy and community were compared to discuss the differences between C. komarovii and other psammophyte plants. The results showed that the reflectance of C. komarovii leaf was higher than that of the flower in 350-2 500 nm and the flower spectra did not appear obvious blue valley and green peak. Sand background has strong influence on the canopy spectra of C. komarovii, which was the combination of the leaf and sand. The main spectral differences between canopy spectra of C. komarovii and other psammophyte plants were the largest red edge slope and obvious high reflectance in 800-1 300 nm. According to spectra changes of C. komarovii communities with different coverage, 4 feature parameters were selected to analysis the linear regression between parameters and community coverage which showed red edge slope had the best result (R2=0.781 5). This study provides scientific basis for monitoring and retrievaling coverage of C. komarovii using remote sensing techniques.
The MaxEnt model and GIS technology were employed to study the responses of Haloxylon ammodendron potential geographical distribution to the hydrothermal conditions in China and the main factors and threshold based on collected geographical distribution of the known coordinates and 20 high-resolution environmental factor layers. The results showed that the potential geographical distribution range were Xinjiang except small amounts in the south and center of Hotan, the southwest of Inner Mongolia, the north of central Gansu, the northwest of Ningxia, the middle of Qinghai Hercynian Mongolian and Tibetan autonomous prefecture and the southwest of Tibetan autonomous prefecture. Among them, the most suitable distribution region were the most regions of Junggar Basin, the southwest of Boluo wild mountain, the southeast of Halitosan mountain and little region in Turpan and Korla. There were scattered distribution in the southeast of Alxa Left Banner, Ordos, Hohehot Municipality and Wulanchabu, the northeast of Wu wei, the most region of Zhang ye, the east of Golmud, the northwest of Ulan and Dulan County. The total area was 2.95×105 km2. The dominate climatic factors influencing potential distribution of H. ammodendron in China were annual precipitation, precipitation of wettest month, annual mean temperature and mean temperature of driest season which had contribution rate of 27.5%, 20.3%, 14.2% and 10.1%, and threshold of 15.0~114.5 mm, 8.0~59.5 mm, -12.7~29.2 ℃ and -33.3~35.9 ℃, respectively. These research results can be applied to the suitable and reserve areas classification and provide reference for management decisions.
Guizhou province is located in the center area of Karst region, its ecological environment has been changed by biological process significantly. It is noted that the plants play an important role in the terrestrial ecosystem as the producer of the biosphere. Therefore, the updated Global Inventory Modeling and Mapping Studies (GIMMS) third generation Normalized Difference Vegetation Index (NDVI) dataset by using global satellite Advanced Very High Resolution Radiometer (AVHRR) was used to investigate the changes of vegetation in the Guizhou Province from 1982 to 2011. The results demonstrated that the overall NDVI increased from 1982 to 2011 with an average rate of 0.002 1 per year (P<0.001). However, there still were two turning points (TP) in 1985 and 1993, respectively. There are large variations between the NDVI trend and TPs in the whole area and in different vegetation types. From the spatial distribution of vegetation growth in Guizhou, the rate of vegetation increased in southeastern was superior to northwestern obviously. One reason was global warming, and meanwhile the vegetation change consisitent with the spatial distribution of precipitation. In addition, the impact of human activities on the changes of vegetation should be paid more attentions.
In the present study, the ammonium nitrogen removal characteristics and nitrogen mass balance in indoor Myriophyllum elatinoides wetland system were analysis. The results showed after 28 days treatment with 200 and 400 mg·L-1 NH4+-N, the removal rates of total nitrogen (TN) and N H4+-N in artificial wastewater were 77.7% and 86.1% , 89.8% and 78.8%, respectively. According to the nitrogen mass balance, 14.7% and 30.2% of the exogenous N H4+-N were transformed into sediment N H4+-N and 25.3% and 11% of exogenous N H4+-N were transformed into sediment NO3-N by 200 mg·L-1 N H4+-N and 400 mg·L-1 N H4+-N treatments; 29.7% and 12.7% of exogenous N H4+-N was absorbed by M. elatinoides; 14.0% and 23.3% of exogenous N H4+-N became residual nitrogen in the water and 16.3% and 22.8% of exogenous N H4+-N eventually to nitrification and denitrification removal. The results suggested that M. elatinoides can effectively purify ammonium nitrogen which provides scientific basis for its application in artificial wetland.
The study on characteristics of vegetation and soil nutritional features of alpine meadow under different degradation gradients were conducted in Tianzhu, Gansu Province. Results showed that the aboveground biomass, vegetation height, coverage, the soil organic carbon, total nitrogen, total phosphorus and soil water contents significantly decreased (P<0.05) along with the degrees of degradation. Soil bulk density in severe degradation significantly increased (P<0.05). Grassland community showed degraded succession significantly such as the dominant species of Kobresia humilis, K. capillifolia, and Elymus nutans were replaced by Polygonum viviparum. The species number decreased from 19 to 7 and the degraded plants biomass fraction increased from 9.77% to 62.93%. The characteristics of vegetation and soil nutritional features could be affected by degradation degrees, so the relevant strategies for restoration should be provided based on degradation degrees.
The carbon content of three shrubs organs were measured in the eastern Inner Mongolia, in order to discuss the problems of the carbon content rate. Results showed that: 1) The biomass of shrub leaf, branch and root accounted for 10% to 20%, 40% to 60% and 30% to 40%, respectively, which showed that branch biomass accounted for half, the root biomass accounted for about a third of the total biomass. 2)The range of carbon content rate of leaf, twigs, roots of natural Prunus sibirica, artificial P. sibirica,artificial Caragana korshinskii and Ostryopsis decne were 0.428 7 to 0.456 7 g C·g-1, 0.445 9 to 0.462 8 g C·g-1, 0.397 3 to 0.431 3 g C·g-1, respectively .The carbon content of the root have a significant difference with the ground organs carbon, the carbon content rate variance between leaves and branches varied with the tree species . 3) When the carbon content rate values of ground parts and root parts of natural P. sibirica, artificial P. sibirica, artificial C. korshinskii, O. decne were 0.45 and 0.42, respectively, the levels of ground carbon density were 1.370 7, 1.167 7, 198.873 and 2.157 3 t·hm-2, carbon density of roots were 0.941 6, 0.401 5, 100.908 8 and 0.721 1 t·hm-2, respectively. The relative errors was within 6% compared with the carbon density calculated by measured carbon content rate of the ground and the root system.
In order to select the turfgrass or varieties that were suitable for greenhouse condition, the heat tolerance and shade tolerance of eight turfgrass species were studied by the comprehensive evaluation of morphological index, physiological index and molecular index. The results showed that: 1) Zoysia matrella and Cynodon dactylon×C. transvadlensis grew best and mignt be optimal species to plant in greenhouse. Z. Japonica, Lippia nodiflora, Paspalum vaginatum, Eremochloa ophiuroides, Agrostis stolonifera, P. notatum did not perform well in greenhouse. 2) The results of comprehensive evaluation for turf resistance by fuzzy clustering analysis were consistent with the morphological index. Z. matrella and C. dactylon×C. transvadlensis ‘Tifgrand' were regarded as the best speices. 3) Meanwhile, the expression of the gene PP2A and GAPDH can also reflect the adaptation ability of turfgrass to greenhouse condition. It was similar to the results of morphological appearance and physiological quality evaluation. Thus, it also improved turfgrass quantitative evaluation and standard system in greenhouse condition.
We summarized overseas and domestic research status and new results in seed ecology, from six aspects including seed traits, seed development, dispersal, predation, seed bank, dormancy and germination, the life processes that seed experienced. The definition and English dictions were given for the important terms. Some central hypothesis, theories and controversial questions were included. We aimed to let the audiences know the main contents and the recent developments in seed ecology. According to the research status and background of climate change, we suggested that maternal effects and the relationship between multiple functional traits of seeds under different environments and climates should be comprehensively and intensively studied.
To identify genetic background and relationships of Desmodium varieties, 92 Stylosanthes EST-SSR markers and 16 varieties from 8 Desmodium species were used to assess the transferability of Stylosanthes EST-SSR markers in Desmodium genus and analyze the genetic relationships among 8 Desmodium species. The results indicated that the transferability of Stylosanthes EST-SSR markers across 8 Desmodium species ranged from 63.04% to 73.91%, and 50 markers of them could produce reliable amplification in all 8 Desmodium species. A total of 35 alleles were generated by 16 polymorphic markers with an average of 2.19 among 16 Desmodium varieties. Cluster analysis showed that 16 Desmodium varieties can be divided into 5 clusters, which was similar to the classification based on morphology. Therefore, Stylosanthes EST-SSR markers showed high transferability in Desmodium, and it would be suitable for germplasm evaluation and genetic relationships analysis of Desmodium.
Seed dormancy and the effects of seven treatments including removing seed stalk, pre-chilling, pre-heating, potassium nitrate (KNO3), gibberellic acid (GA3), soaking in distilled water and soaking in boiled water on breaking seed dormancy of Hordeum jubatum collected in Linze County, Gansu Province, China were investigated. The results showed that the dormancy percentages of tested seeds were 73%~77%. Treatments of pre-chilling, pre-heating, KNO3, GA3 and soaking in distilled water significantly improved (P<0.05) germination of tested seeds and pre-chilling and GA3 treatments had the best effects. After pre-chilling and GA3 treatments, seed germination percentage and germination index reached highest which were 92%, 89% and 42.99, 39.80, respectively, mean germination time were the shortest which were 2.43 and 3.10 d, respectively. Both treatments of removing seed stalk and soaking in boiled water did not improve seed germination anyways. The tested seeds had non-deep physiological dormancy.
In order to study the germination characteristics of Miscanthus sinensis seeds, the influence of temperature, light time, soil water content and sowing depth on the seed germination and seedling growth were studied. The results indicated that the optimal temperature for M. sinensis seed germination was 25 ℃, and seed germination and seedling growth were inhibited under less than 10 ℃ treatment. The light time significantly influenced (P<0.05) the germination index, vigor index and seedling growth, and the optimal light time was 12 h although it had no effects on the germination rate. The most optimal soil water content was 10%, and M. sinensis seed germination were seriously inhibited (P<0.05) under 25% soil water content treatment. 4)Sowing depth had significantly (P<0.05) influence on the emergence rate and seedling growth. The most appropriate sowing depth was 3 mm. These results presented the information of the M. sinensis seed germination in the greenhouse and field.
Scanning electron microscopy was carried out to analyze the leaves of 20 Eulaliopsis binata germplasm resources. The results showed that there were significant differences in leaf length, leaf width, leaf area, leaf epidermis, leaf thickness, leaf stomatal density, leaf stomatal length, leaf stomatal width, leaf cell diameter, cell wall thickness, cavity diameter, and cavity wall ratio in leaf anatomical structure. Based on the cluster analysis of the cavity wall ratio as the important indicator of preferred paper material, the papermaking performance of tested E. binata germplasm resources will be categorized as the optimal, the good, the bad and the worst. The results can provide the basis for breeding and E. binata germplasm resources exploitation research in hilly area of southern China.
The aim of this study was to evaluate the salt resistence of different Elymus sibiricus germplasm and to screen varieties with salt resistance. The seeds of nine E. sibiricus were treated with different NaCl solutions of 0, 0.3%, 0.6%, 0.9%, 1.2%, 1.5% and 1.8%, to select the best concentration of NaCl solution. The salt stress of nine accessions was studied in germination index and seedling leaf physiological indexes. The results of this study showed that the salt decreased the relative germination rate and relative germination index, inhibited the growth of radicle length and plumule length. It was obvious that the level of SOD enzyme activities, MDA, proline in the leaves at seedling stage were sensitive to the level of salt stress. The concentration of 0.9% NaCl was suitable for screening salt tolerance in E. sibiricus at seed germination stage. According to the descending order of the comprehensive evaluation of salt resistance, the order of nine E. sibiricus accessions from high to low was E03, E04, E08, E09, E07, E05, E06, E02, E01.
Soil salinization is a serious worldwide problem which causes heavy losses of agriculture production. Plants with higher salt tolerance has been considered as a best way to control the saline soil. In the present study, the effects of saline-alkaloid stress on growth including the survival rate, plant height and biomass and biochemistry including chlorophyll, proline, soluble sugar, MDA and SOD activities of Elytrigia repens new variety “Nong Jing No.7” were studied. The results showed that the survival rate, plant height and biomass of E. repens decreased under saline-alkaloid stress. The survival rate significantly decreased (P<0.05) under treatment over 80 mmol·L-1 concentration of saline-alkaloid. There was a very significant negative relationship (P<0.01) between saline-alkaloid concentration and plant height and biomass. The chlorophyll content increased and then decreased with saline-alkaloid concentration increased which reached peak under treatment of 80 mmol·L-1. The contents of soluble sugar and MDA and SOD activities increased with saline-alkaloid concentration increased. All these results showed that saline-alkaloid stress had negative effect on the seedling growth of E. repens, and the physiological and biochemical indexes of E. repens changed to adapt to the saline-alkaloid environment.
The effects of silicon on chlorophyll content and gas exchange characteristics of two different ecotype varieties switchgrass (Panicum virgatum) including Alamo(lowland) and Cave-in-Rock(upland) under salt stress were investigated. The concentrations of NaCl and Si NaSiO39H2O were 0, 50, 100, 150 mmolL-1 and 0, 0.5, 1, 2 mmolL-1, respectively. The results showed that the chlorophyll contents of Alamo decreased significantly (P0.05) under salt stress, but that of Cave-in-Rock slightly increased. The net photosynthetic rate (Pn) and stomatal conductance (Gs) of Alamo increased at 50 mmolL-1 NaCl level, then decreased at 100 and 150 mmolL-1 levels of NaCl concentrations. Pn, Gs and intercellular CO2 concentration (Ci) of Cave-in-Rock decreased significantly (P0.05) with increasing NaCl levels. Optimal concentration of exogenous silicon addition had alleviated the reduction of chlorophyll and improved gas exchange ability of Alamo and Cave-in-Rock under salt stress. In our study, 1-2 mmolL-1 was the optimal concentration of silicon (Si).
A fertilizing experiment was conducted in a fenced enclosure in Bange County, which was a typical alpine grassland in Tibetan from July 2013 to September 2014. The aboveground biomass, group coverage, evenness and important values (IV) were assessed under controlled experiment with different nitrogen(N) application level [control, 0(N0); low level, 7.5 g·(m2·a)-1(N1)] high level, 15 g·(m2·a)-1(N2)] to find out the effects of N fertilization on different vegetation communities characteristic of the degraded alpine steppes in Tibetan. The results showed that Gramineae and the total biomass significantly increased compared with the control group without N fertilization, however, high nitrogen application only increased the aboveground biomass of Compositae without significance. There was no significant influence of short term nitrogen application on the coverage of Gramineae, Compositae, Cyperaceae, Rosaceae, forbs and total coverage, while the proportion of Gramineae in the total coverage gradually improved, which was 58.73%, 61.90% and 63.99%, respectively, with different N level (control, low level and high level). There was no significant difference between evenness, important values and the dominant species of all communities in response of different N level.
Ten alfalfa varieties were selected to explore the adaptation and production performance in agro-pasture ecotone of north Shanxi, the overwintering rate and the yield were observed and investigated in field plots through two years. The results showed that the overwintering rate, hay yield, stem to leaf ratio and nutritional content of different alfalfa varieties had significant difference (P<0.05); the overwintering rate of WL-168HQ, Sanditi, Queen and Zhongmu No.1 were significantly higher than other varieties; the hay yield of Zhongmu No.1 was significantly higher than that of others except Queen; and the stem to leaf ratio of different alfalfa had greatly significant difference with the increasing of mowing frequency, and the nutritional content of different alfalfa varieties have extremely significant difference(P<0.01). Based on the demand of actual production (overwintering, yield and quality), Zhongmu No.1, Sandati and Algonquin were more suitable for promoting in this region than others through the comprehensive analysis.
In this study, different special silage maize varieties (lines) were introduced and tested, in order to screen varieties suitable for summer sowing in the Yellow River Delta Area. Grain and forage maize variety was used as the control. Growth periods, agronomic traits, resistance, fresh yield and hay yield were observed and measured. The results showed that fresh yield of silage maize varieties was higher than that of the control in addition to Yayu No. 26. The fresh yield of Gui No. 1 was higher (69 802.5 kg·hm-2). Gui No. 1 has excellent characteristics, such as strong stem tough, high lodging resistance, low stem to leaf ratio (1.833). It has excellent forage quality. It was considered that Gui No. 1 was suitable for summer sowing in the Yellow River Delta Area as the main cultivars of silage maize.
Reed canarygrass Tongcao No.1(Phalaris arundinacea cv. Tongcao No.1) was used as test material, two factors of nitrogen application level (0, 46, and 92 kg·hm-2) and row spacing (30,50 and 70 cm) were designed, a field complete split-plot experiment was conducted to study the effects of row spacing and nitrogen fertilizer application level on the yield and nutritional contents of reed canarygrass at different growth stages. The results showed that: the yield and quality of reed canarygrass were influenced significantly by nitrogen fertilizer application level and row spacing.With an increase of nitrogen level, forage yield and contents of crude protein, calcium and phosphorus of reed canarygrass increased and the nitrogen free extract contents decreased at different growth stages. CF content and ADF content of reed canarygrass at heading decreased and increased at maturity stag and regrowth stage. The yield of reed canarygrass at different growth stages decreased with an increase of row spacing. Among nine treatment combinations, there were higher forage yield in A30B92 treatment at heading and maturity stage, and there was higher forage quality in A70B92 treatment. Reed canarygrass Tongcao No.1 can obtained higher forage yield and crude protein content when the planting row spacing was 30 cm and the nitrogen rate was 92 kg·hm-2, and the period of suitable cutting utilization was heading stage.
The influence of different mowing system (continuous mowing and biennial mowing) on fenced Leymus chinensis grassland in Hulunbeier were studied. The results showed that community coverage and aboveground biomass significantly decreased under mowing treatment. The biennial mowing was better than continuous mowing in quantitative characteristics of community and biomass. The community average height, coverage and the aboveground biomass of community decreased with the increase of mowing frequency whereas the plant community α-diversity index increased with the increase of mowing frequency which was the lowest in fenced grassland without mowing. The composition of plant community and the important value of each species in the community changed a lot under different mowing system. The important value of L. chinensis under continuous mowing was lower than that under biennial mowing, however, the important value of Carex duriuscula was the highest under continuous mowing. The important value of other associated species decreased with mowing frequency.
The difference between actual and potential yields of crop is called yield gap. Potential yield reflects the theoretical upper-limit of crop production in a certain region. Prediction of crop potential yield can help confirm the upper-limit of crop yield and have an insight into the study and analysis of yield gap and limiting factors of yield. This paper summarized the current progresses in the studies of potato potential yield and proposed the priorities in the study of potato potential yield in the future. The difference between actual and potential yields of crop is called yield gap. Potential yield reflects the theoretical upper-limit of crop production in a certain region. Prediction of crop potential yield can help to confirm the upper-limit of crop yield and have an insight into the study and analysis of yield gap and limiting factors of yield. This paper summarized the current progresses in the studies of potato potential yields. The current main problems in the research on the potential yield of potato lies in that the concept, calculation and analysis methods and the analysis mechanism among crop models are different, which result in the analysis results are quite different. In the future, the research on the potential yield of potato should focus on that the growth model of potato is combined with the new techniques of remote sensing technology (RS), geographic information system (GIS), and the study method should change from original single analysis
According to the lactation yields (0.8, 1.0 and 1.2 kg, respectively) and feeding standard of 40 kg Chinese Merino lactation ewes, three daily rations (Ⅰ, Ⅱ and Ⅲ) with different nutritional levels corresponding to the forage to concentrate ratios of 5∶5, 6∶4 and 7∶3 were confected in this study. These rations were used to conduct grazing supplementary feeding experiment in winter and spring for Gansu Alpine Merino, and those lactation ewes of feeding a small amount of concentrates, niblet and large number of green hay were designed as control group. By measuring the serum biochemical indicators of experimental sheep from each group and the change of body weight of ewes and lambs of Gansu Alpine Merino, this study aimed to explore an appropriate forage supply and nutritionally balanced model. The results suggested that the content of serum GLU by feeding diet Ⅲ was the highest, which extremely significantly higher than that of control group (P<0.01). The content of BUN in control group was significantly higher than those of another 3 groups (P<0.05), while the content of CHO in diet Ⅱ was significantly (P<0.05) or extremely significantly (P<0.01) higher than those of another 3 groups. The contents of TP, ALB, AST, ALT in diet Ⅱ was in the highest level, and significantly higher than that of control group (P<0.05), while the content of LDH in diet Ⅱ and Ⅲ were significantly lower than those of another 2 groups (P<0.05). The average daily gain of ewe in groups fed by diet Ⅱ and Ⅲ was significantly (P<0.05) or extremely significantly (P<0.01) higher than those of another 2 groups. Correspondingly, average daily gain of lambs in diet Ⅱ and Ⅲ groups was significantly higher than other two groups. Overall, there exists significant influence on serum biochemical indexes and weight of lambs by feeding diet Ⅱ and Ⅲ. However, in order to reduce the feeding cost and avoid the excess of energy and protein, feeding diet Ⅱ along with grazing is the optimal option.
We conducted yard-feeding experiments on goats in order to improve the methods for raising and breeding of cashmere goats in Huanxian County in winter. The traditional method in Huanxian County of “grazing and supplementary feeding” (hereafter, GS) served as the control group. A 60-day yard-feeding (hereafter, Y) experiment was conducted using six-month-old Ziwuling black goats and F1 hybrids of Liaoning Cashmere goats (♂) ×Ziwuling black goats (♀) (hereafter, F1). Growth results, slaughter performance, and meat quality were systematically measured and economic return was calculated. The final weight, weight gain, average daily gain, carcass weight and dressing percentage in Y group were higher than those in GS group in both experimental goat populations (P<0.01). Average daily gain, carcass weight, and dressing percentage of Ziwuling black goats in Y group were 102.5 g, 10.75 kg, and 47.66%, respectively, which were higher than the corresponding values of 87.2 g, 3.46 kg, and 12.54% in GS group. Average daily gain, carcass weight, and dressing percentage of F1 in Y group were 117.2 g, 11.71 kg, and 49.62%, respectively; these values were also higher than the corresponding values of 96.7 g, 4.16 kg, and 13.83% in GS group. Water loss rate and meat tenderness in Y group were lower than those in GS group (P<0.05), but no significant differences were observed between these groups with regard to other meat quality indexes. Net income of Y group from Ziwuling black goats and F1 hybrids were 110.2 and 75 CNY, respectively, higher than those of lambs of the same breed in GS group. These results suggest that yard-feeding can increase growth results and meat performance, and improve some meat quality indexes and cultural benefits of the cashmere goats of Huanxian County in winter.
This paper briefly analyzed the meaning of developing grass and animal husbandry and the existing problems in rocky desertification area. In view of the problems of the fragile ecological environment, small geographical unit and small and scattered farm size in Rocky Desertification area, the breakthrough point of the development of grassland animal husbandry is to establish a silage center and distribute the farms in the area. From the technical feasibility and benefit analysis of establishing a silage center in Rocky Desertification area, it is significant for developing grassland animal husbandry to build a silage center and intensive farm..
Pratacultural Science is a science of grassland agricultural system from grassland resources to grassland agricultural production. The characteristics of the discipline requires close connection between theory content and practice. The effectiveness of practice course reflects the mastery degree of grass course content. However, with the rapid development of Chinese forage and turf industry, several issues have exposed, such as the obsolete teaching content of the practice teaching course, unreasonable course time and content distribution, monotonous teaching methods, lack of educational resources, and irrational performance evaluation. The teaching form and contents have been unable to meet the demand. Therefore, on the basis of the traditional Pratacultural Science practice, the teaching model should be reformed including adopting the flexible and diverse teaching methods, optimizing the teaching content, increasing the practice teaching resources, and improving the performance evaluation methods to mobilize students' enthusiasm.The final teaching reform has achieved better teaching results. The teaching goal is more inclined to foster students' thinking ability, and enhance their horizons on professional knowledge. Moreover, a useful attempt in building a training system covering industry, learning and researching has been done.
Due to increased consumption of fossil energy and its pollution to the environment seeking renewable and clean energy has become the focus of attention in many countries. Lignocellulose is the most organic polymer on the earth, which has great potential for solving the energy crisis, but it has not been effectively used, the existence of the crystalline region of cellulose is a major problem hindering its degradation. This paper introduces the structure of crystalline cellulose, decrystallization method and potent degradation strain; the structure and function of cellulase; degradation mechanism of crystalline cellulose; genetic engineering and enzyme engineering modification of cellulase. It is underlined that should increase to excavate for the excellent, thermostable cellulose-degratdaion strains and thorough study of related function mechanism of carbohydrate binding module, it is of great significance for the efficient degradation of crystalline cellulose.