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RSS2018 Vol. 40 Issue 2
2018, 40(2): 1-10.
DOI: 10.13332/j.1000-1522.20170284
Abstract：
ObjectiveForest biomass is one of the important indexes to evaluate the structure, function and productivity of forest ecosystem, and accurate forest biomass estimation on regional scale has great significance in understanding the current forest status and scientific forest management. This study aims to quantify regional scale forest biomass through the polarimetric SAR and Landsat5 TM. MethodFirstly, SAR data was polarized by polarization decomposition. Then 51 parameters from 45 polarization decomposition parameters and 6 TM bands were used as predictor variables with forest biomass W as response variables, the best model was used in the research area finally. ResultTwo methods were implemented for model construction: (1) stepwise regression, the final model includes two variables with R2 of 0.534, predicting accuracy of 67.51% and RMSE of 43.21 t/ha; (2) Optimal subset method, Bootstrap was applied to select 9 parameters. Then, we got 511 models by optimal subset method and cross-validation was used for model validation. The final model had 5 parameters(TM_band4, Neumann_delta_mod, Neumann_psi, TSVM_psi, TSVM_tau_m3), R2 of 0.768 2, simulating accuracy of 88.32%, simulating RMSE of 14.98 t/ha, test accuracy of 86.21%, test RMSE of 19.14 t/ha, Mallows'Cp of 5.249 5 and AIC of 256.504 5 t/ha. We used optimal subset method to build forest biomass estimation model and acquired forest biomass distributing map. ConclusionThe results show that C band polarimetric SAR and optical Landsat5 TM data can get accurate estimation of forest biomass.
2018, 40(2): 11-21.
DOI: 10.13332/j.1000-1522.20170317
Abstract：
ObjectiveTo provide evidences for selecting appropriate poplar clones for southern mountain area in China, the responses to sunlight and adaptability to habitat for Populus deltoides cv. 'I-69'(♀)(F), P. cathayana (♂) (M) and 3 types of hybrid F1, including female-parent-like (FP), intermediate (I) and male-parent-like (MP), were compared and analyzed. MethodThe diurnal changing pattern of twist angles and midrib angles and leaf morphological indexes were measured, and anatomical structures of leaves and petioles were observed by scanning electron microscope. ResultThe co-operation of changing in twist angles and midrib angle led to leaf movement for maternal F, while the movement of midrib angles was mainly forced for paternal M. The response to sunlight by changing the leaf orientation for 3 types of F1 was not significant. Obvious differences in anatomical structure were found in parental poplars and F1 types. As the types of isobilateral leaf, F and FP possessed the ratio of 0.87 and 1.02 for stoma density on the upper to the lower of leaf epidermis, no sponge tissue was observed, and 2 layers of palisade tissue, located in the upper and lower of leaf, occupied more than 0.7 of total thickness of leaf. As the types of bifacial leaf, including F, I and FP, the ratios of stoma density on the upper to the lower of leaf epidermis were 0.08, 0.45 and 0.55, respectively; thicker sponge tissue and palisade tissue on the upper leaf were observed, and the rank of the ratio of palisade tissue to sponge tissue was MP(0.75)>I(0.55)>M(0.47). Anatomical structure of F petiole showed the tendency of cross-section shape varying from narrow-oval to wide-heart-shape, with a gradually changing arrangement of vascular bundle from vertical to horizontal along the upper to lower section of petiole. While the structure of M petiole showed small variation, from near round to heart-shape in shape, and radial pattern in arrangement of vascular bundle from the upper to lower section.However, for 3 types of F1, both the shape and arrangement of vascular bundle intervened two parents. ConclusionThe results provide possible appropriate poplar clones for South China: I and MP type of F1 are nominated for mountainous area of high altitude; meanwhile, FP may adapt to mountainous area of low altitude.
2018, 40(2): 22-30.
DOI: 10.13332/j.1000-1522.20170245
Abstract：
ObjectiveGA20ox is one of the genes coding key rate-limiting enzymes, GA20-oxidases (GA20ox), for biosynthesis of bioactive gibberellins (GA) which involve in many biology process of plant growth and development. At present, it is still not clear that the biological function of GAs in plant leaf development. The aim of this research is to reveal the roles of PsnGA20ox1 in the leaves of overexpression tobacco. MethodIn this study, we systematically analyzed the leaf size, ultrastructure, biomass, chlorophyll and bioactivity GAs contents, and gene expression level involved in cell division and stomatal formation of PsnGA20ox1 overexpression tobacco and wild-type plants. ResultOur results revealed that the PsnGA20ox1 overexpression tobacco displayed the enlarged leaf size, enhanced chlorophyll and GA4 contents, and decreased epidermal cell size. In addition, the thickness of palisade and spongy parenchyma, the sizes of epidermal cell, the numbers of stomatal and epidermal cell, and photosynthesis and leaf biomass productivity of PsnGA20ox1 overexpression tobacco were notably increased compared with wild-type tobacco, respectively. Furthermore, the expression levels of genes involved in cell division and stomatal formation in PsnGA20ox1 overexpression tobacco altered notably, and the variation tendency was in accordance with the alternations of leaf trait. ConclusionThe results demonstrated that the overexpression of PsnGA20ox1 had effect on the structure and development of leaf in the transgenic tobacco, which is beneficial to the accumulation of biomass of leaf.
2018, 40(2): 31-39.
DOI: 10.13332/j.1000-1522.20170426
Abstract：
ObjectiveThe clonal growth of Populus euphratica plays an important role to the recruitment and persistence of the population in arid-climate region, and the change in branching pattern of clonal roots is a key process for P. euphratica to achieve the clonal growth in heterogeneous environment. This paper attempts to clarify the branching pattern of clonal root system of P. euphratica in heterogeneous riparian habitat, to estimate the correlations between branching traits of clonal roots including internal length (IL), branching intensity (BI), vertical-and horizontal-branching angle (VBA and HBA), and soil factors, and then to find the key factors driving changes of the branching pattern. MethodWe investigated 16 clonal root branches over 10 m by manual digging and collected below-ground environmental factors correspondingly in a natural floodplain of Ejin Oasis, Inner Mongolia of northern China. Correlation and ordination of the branching traits of clonal root were analyzed using correlation analysis (CA) and principal component analysis (PCA). Redundancy analysis (RDA) and variation partitioning (VP) were applied to explore the relationship between root branching traits and soil factors. Result(1) The results of CA and PCA showed that there was a high correlation between the four branching traits (P < 0.05), and the first axis, reflecting 66.88% variation of the branching traits, can represent the changes from guerrilla-branching type (with sparser and longer branches, smaller branching angle in vertical and horizontal) to occupation-branching type (with denser and shorter branches, steeper branching angle in vertical and wider branching angle in horizontal). The former more occur on the edge of the river, and the later more on the edge of the forest. (2) The results of RDA revealed that VBA was mainly affected by soil compactness positively (R2=0.64, P < 0.05), and IL was mainly affected by it negatively (R2=0.87, P < 0.05). Soil total carbon and total nitrogen had a major positive influence on BI and HBA, but soil sandy content had a negative effects on them. The depth of branching points of clonal root was positively controlled by capillary water depth (R2=0.62, P < 0.05). (3) VP results showed that the three set of soil variables including soil nutrient-related, water-related and physical factors explained a total of 68.3% of the variance of P. euphratica branching traits. The independent effects of soil physical factors (soil texture, compactness) were the highest (R2=0.12, P < 0.05). Nutrient- and water-related factors had relative smaller independent effects (R2=0.07, P < 0.05; R2=0.03, respectively), but they had a greatest together influences with soil physical factors to variance of the branching traits (R2=0.23, P < 0.05). Conclusion(1) Guerrilla-branching type and occupation-branching type are two main branching pattern of clonal roots for P. euphratica to vegetative propagate in heterogeneous floodplain of arid region. (2) Soil physical factor is the most important factor to drive changes in branching pattern of the clonal roots. P. euphratica tends to develop an occupation-branching clonal roots in soil patches with less sandy and smaller compactness to establish its ramets. (3) The vertical branching angle of clonal roots of P. euphratica expresses a significant ecological plasticity, it may be an important adaptive trait of clonal roots for woody plant that should be paid attention in the future researches of clonal plant.
Abstract：
ObjectiveIn order to provide scientific basis for further research of carbon release and its influence on the regional climate in cold temperate region of China, the characteristics of soil respiration and its components, and their correlations with soil temperature and humidity were analyzed in larch forests of the Daxing'an Mountains of northeastern China. MethodWe used LI-6400 chamber to measure soil respiration, respiration components and their impacting factors of five typical forest types, which were dominated by larch (pure Larix gmelinii forest, Rhododendron dauricum-Larix gmelinii forest, Ledum palustre Larix gmelinii forest, Betula platyphylla-Larix gmelinii forest, Pinus sylvestris var. mongolica-Larix gmelinii forest) in the north of the Daxing'an Mountains. ResultThe rates of total soil respiration(RS), heterotrophic respiration(Rh) and root respiration(Rr)all presented a single-peak curve in growing season, and the peak values all appeared in August for the five kinds of larch forests. The average soil respiration rates of the five communities ranged from 4.71 to 7.41 μmol/(m2·s), and their rank was Pinus sylvestris var. mongolica-Larix gmelinii forest>Ledum palustre-Larix gmelinii forest>Betula platyphylla-Larix gmelinii forest>pure Larix gmelinii forest>Rhododendron dauricum-Larix gmelinii forest (P < 0.05). The Rh and Rr also had significant differences in the five types of larch forest (P < 0.05).The average of Rh ranked as Pinus sylvestris var. mongolica-Larix gmelinii forest (5.56 μmol/(m2·s))>pure Larix gmelinii forest (4.64 μmol/(m2·s))>Betula platyphylla-Larix gmelinii forest (4.55 μmol/(m2·s))>Ledum palustre-Larix gmelinii forest (4.27 μmol/(m2·s))>Rhododendron dauricum-Larix gmelinii forest (3.80 μmol/(m2·s)). The average of Rr ranked as Ledum palustre-Larix gmelinii forest (3.15 μmol/(m2·s))>Pinus sylvestris var. mongolica-Larix gmelinii forest (2.98 μmol/(m2·s))>Betula platyphylla-Larix gmelinii forest (2.76 μmol/(m2·s))>Rhododendron dauricum-Larix gmelinii forest (2.30 μmol/(m2·s))>pure Larix gmelinii forest (1.97 μmol/(m2·s)). Rh was the major component of soil respiration, which accounted for 61.84%-71.76% of the total soil respiration. The soil mineral respiration (Rm) was the main component of Rh, which accounted for 46.28%-58.18% of the total soil respiration. However, the soil litterfall respiration (Rl) only accounted for 8.34%-15.57% of the total soil respiration. Rr accounted for 28.24%-38.16% of the total soil respiration. There was a significantly positive correlation (P < 0.05) between soil respiration rate and the temperature of top 10 cm soil (T10). T10 could explain 43.6%-57.0% of seasonal variation for soil respiration. But the correlations between soil respiration rate and soil humidity were different among the five types of larch forests. ConclusionThere are significant differences among the soil respiration and its components of the five types of larch forests. Temperature is the dominant factor influencing soil respiration, the influence of humidity on soil respiration is weak in the larch forests in the northern Daxing'an Mountains of northeastern China.
Abstract：
ObjectiveTo study the effects of natural zeolite on modifying the water retention capacity of chernozem and provide theoretical reference for the improvement of soil water retention, the effects of natural zeolite on the physical and chemical properties of chernozem in Songnen Plain of northeastern China and soil water characteristic curve were studied. MethodChernozem was modified by natural zeolite, cultured in a pot for 60 days. The soil bulk density was measured by cutting ring method. Soil total porosity, capillary porosity and aeration porosity were calculated by formula method. Determination of soil water characteristic curve was measured by centrifuge test. ResultThe results showed that there was a positive correlation between soil bulk density and the amount of natural zeolite, soil bulk density increased with the increasing amount of nature zeolite. Soil bulk density increased significantly at the 10% mixing amount of natural zeolite. However, there was a negative correlation between the capillary porosity and total porosity and the amount of natural zeolite, the capillary porosity and total porosity decreased with the increasing amount of natural zeolite. The maximum ventilation porosity was obtained at the 10%mixing amount of natural zeolite. The result of the water retention capacity of different mixing amount of natural zeolite was: 20% natural zeolite (NZ)>15%NZ≈10%NZ>5%NZ>CK. The soil water characteristic curve of each group can be fitted well by Gardner model. The coefficients a and b of water characteristic curve equation were negatively correlated with water holding capacity, and positively correlated with saturated water content. The saturated water content and the fitting coefficient a were fitted too. The results showed that R2 is 0.941 8. ConclusionIt is feasible and economical to improve water retention capacity of chernozem by 10% mixing amount of natural zeolite. The saturated water content is high, the initial level of water characteristic curve is not necessarily high yet. The results show that the water retention properties of chernozem can be effectively improved by mixing natural zeolite. This study provides a theoretical and experimental reference for soil improvement in chernozem.
2018, 40(2): 58-67.
DOI: 10.13332/j.1000-1522.20170251
Abstract：
ObjectiveWater and fertilizer are two key factors to promote plant growth, thus, it is important to study their coupling effects on growth and nutrient status of Catalpa bungei seedlings. MethodThe pot experiment with Catalpa bungei seedlings in three different water levels (30%, 50% and 70% saturated water content(FWC)) with four fertilization levels of T1(N 0g, P 0g, K 0g), T2(N 2g, P 1g, K 1.5g), T3(N 4g, P 2g, K 3g), T4(N 6g, P 3g, K 4.5g) was conducted to study the coupling effects of water and fertilizer on growth, nutrient absorption and fertilizer utilization. ResultThe interactive effects of water and fertilizer coupling on morphological indexes of Catalpa bungei seedlings were not significant. Root collar diameter, height, and biomass of seedlings decreased with rising water level, reaching the top at 30% saturated water content, but firstly increased and then decreased with increasing fertilization level, reaching peak at T3 fertilization level. The nutrient content of seedlings reached a luxury nutrient state at T3 treatment, meanwhile seedling height, root collar diameter, biomass and nutrient content of seedlings were the highest. If more fertilizers were applied on seedlings, it would occur toxic effects. Since at T3 treatment, although the nutrient concentration of seedlings was increasing, the morphological indexes and nutrient content decreased. There were interactions of water and fertilizer coupling effects on nutrient concentration and nutrient content of Catalpa bungei seedlings. Nutrient content rose with increasing fertilizers, and reached the peak under T3 treatment. When water content was 30% FWC, fertilization had a greater promotion for seedlings of Catalpa bungei. ConclusionIt proves that water and fertilizer coupling effects promote the quality of seedlings. Furthermore, 30% FWC and T3 treatment was the best combination for cultivating seedlings of Catalpa bungei.
Abstract：
ObjectiveThis paper is to understand the species composition and spatial distribution of tree seedlings in a coniferous and broadleaved mixed forest in Changbai Mountain of northeastern China. It may provide a theoretical basis for management. MethodBased on a permanent plot in the coniferous and broadleaved mixed forest and continuously field survey tree seedlings and adult trees within 1 ha, we analyzed species composition and spatial distribution of typical coniferous tree and broadleaved tree seedlings. The relationship of spatial distribution between seedlings and adult trees was further researched. ResultThe results showed that:(1) a total of 17 tree species were recorded in this plot which was consistent with the composition of adult trees, and there were 10 865 tree seedlings recorded; (2) seedlings of typical coniferous trees(Pinus koraiensis, Abies nephrolepis)and broadleaved trees(Fraxinus mandshurica, Tilia amurensis)were characterized by clumped distribution on the scales less than certain critical points; (3)the spatial distribution of F. mandshurica and T. amurensi's seedlings was positively correlated with their adult trees, while that of P. koraiensis and A. nephrolepi's seedlings was negatively correlated with their adult trees. ConclusionAll above, in the coniferous and broadleaved mixed forest, spatial distribution of typical coniferous tree and broadleaved tree seedlings showed clumped distribution, and the typical broadleaved tree seedlings were positively correlated with their adult trees while the typical coniferous tree seedlings showed negative correlations with their adult trees.
2018, 40(2): 76-81.
DOI: 10.13332/j.1000-1522.20170338
Abstract：
ObjectiveThe relationship between the evolved strategies of plant species and the material and energy cycles of ecosystems is linked by plant biomass and nutrient allocation, and the pattern of plant resources allocated to its different components is a fundamental aspect of its biological characteristics. In this paper, the scaling from components to whole plant in biomass and nitrogen content of Nitraria tangutorum seedlings was researched in the northeast of Ulan Buh Desert, Inner Mongolia of northern China. MethodFirstly, we measured the biomass of root, stem and leaf of Nitraria tangutorum, individually, and we converted them into a value of logarithm (base 10) to get the linear fitting equation of the stem biomass or root biomass taking leaf biomass as variable. Then we measured the nitrogen concentration of each component, also, we linearly fitted the nitrogen concentration of the leaf and the stem or root for further study. ResultThe results showed that the biomass of stem and root could be predicted accurately by giving the leaf biomass (R2 of root-leaf and stem-leaf regression equations were 0.901 2 and 0.926 4, respectively). And the nitrogen concentration of root and stem also could be predicated well by giving the leaf nitrogen concentration too (R2 of root-leaf and stem-leaf regression equations was 0.850 1 and 0.844 7, respectively). Then we obtained the prediction model of the whole plant biomass by adding the three parts of plant: Mp=ML+100.020 9ML0.845 6+100.436 9ML0.867 8, and we inferred the nitrogen content predicting model of whole plant by adding the three parts together similarly: Np =MLNL+100.020 9ML0.845 6 (0.109 4NL+0.015 6)+100.436 9ML0.867 8 (0.108 8NL+0.014 8). And through the field data verifying, it was showed that the relationship between the biomass and nitrogen content of whole plant could be predicted by the biomass and nitrogen concentration of Nitraria tangutorum leaves:lgN′p =1.075 2lgM′p-1.768 4. ConclusionIt was showed that the biomass and nitrogen content of the whole plant of Nitraria tangutorum can be predicted by its components.
Abstract：
ObjectiveGrassland fire is a key disturbance factor in natural ecosystems and it greatly influences ecosystem structure and function. XinBarag Prairie of northwestern China is one of the important grassland ecosystems in China. With the frequent occurrence of extreme weather events, more extra serious wildfires will occur in this region. This study could provide a scientific basis for zoning grassland fire risks and wildfire management. MethodIn this study, the spatial and temporal patterns of wildfires in XinBarag Prairie were analyzed using statistical software, GIS and ENVI based on MODIS data from 2001 to 2016. Through the integration of meteorological data, the impact of meteorological factors on the characteristics of monthly variations in grassland fire was investigated. ResultXinBarag Prairie had regular distribution in the spatial and temporal patterns of wildfires. In the temporal patterns, annual burned area had a fluctuation period of 10 years generally in the whole region. The monthly burned area had significant differences among various months and the burned area was mainly distributed in April, May, September and October. The time corresponds to spring and autumn, in which fire disaster occurred frequently. In spatial patterns, the high frequencies of wildfires were all widely distributed near the country s borders. The large-scale fires crossing the border line will pose a serious threat to the steppe in China; There were close relations between grassland fire and meteorological factors. Grassland fires easily occurred and spreaded in areas with monthly average temperature ranged between 0 and 10 ℃, monthly total rainfall ranged between 0 and 20 mm, monthly mean relative humidity was below 40% and monthly mean wind speed was above 5 m/s. ConclusionThe preventing region of grassland fire in XinBarag Prairie should concentrate in its western, southeastern and northeastern regions, and the monitoring and management of grassland fire in border region should be strengthened.In time, we should concern April, May, September and October, especially the areas with monthly average temperature between 0 and 10 ℃, monthly total rainfall between 0 and 20 mm, monthly mean relative humidity below 40% and monthly mean wind speed above 5 m/s. In addition, future research will focus on the fluctuation period of grassland fire from longer temporal and wider spatial scale to explore the dynamic change of wildfires and its influencing factors more effectively.
2018, 40(2): 90-97.
DOI: 10.13332/j.1000-1522.20170353
Abstract：
ObjectiveThe guardrail is an important protection measure for the safety of highway traffic, but the single design can't adapt to various environments. With the practical activity in the sand area, it is found that banded sediment often appears in the sections of the guardrail. In view of this situation, on the basis of field investigation, from the perspective of aerodynamics, this study is to provide a solution for deposited sand in sandy region. MethodTaking the highway guardrail as the research object, and reforming the guardrail with different porosity and orifice types, using wind tunnel simulation, Kriging interpolation and other methods, the impact of different guardrail on wind velocity flow field was analysed, and the impact of different types of guardrail on the absolute sediment concentration was calculated to select the appropriate configuration to achieve the purpose of preventing sand in the road. ResultThe wind speed near the surface on the lee side of the traditional guardrail decreased to 80% of the original wind speed. Under the conditions of 5, 8 and 11 m/s, the absolute sediment concentration decreased by 44.7%, 64.8% and 75.1%, blocking effect of guardrail on wind sand flow is an important factor leading to the road sand. The new guardrail can improve the absolute sediment concentration of sand flow, and the effects of macropore and small hole guardrail on absolute sediment concentration had no obvious regularity with the porosity but lower than the initial level. The influence of strip on the absolute sediment concentration decreased with the increase of porosity. When the porosity reached 0.3, the absolute sediment concentration reached the initial level. In the near-surface layer with the highest sediment concentration in the wind-blown sand structure, the influence of different hole-type guardrails on the wind speed showed a consistent regularity, which decreased with the increase of the porosity. The stable wind speed at the leeward side of the macroreticular and the small fence was smaller than the initial wind speed under the condition of different porosities. The stability velocity of the strip guardrail with porosity of 0.3 and 0.4 reached the initial wind speed. From the wind speed flow field, at the leeward side of the traditional protection fence, obvious deceleration zone and low speed zone were formed along the wind direction, and the wind speed flow field structure of strip hole guardrail was more stable. ConclusionThe guardrail with 0.3 and 0.4 porosities can improve the wind speed flow field and prevent sand accumulation in sandy region. In the future, research on guardrail should adapt to different driving environments based on safety standards so as to make full use of the guardrail.
2018, 40(2): 98-105.
DOI: 10.13332/j.1000-1522.20170379
Abstract：
ObjectiveLilium spp. is one of the main commercial flowers in the world which possesses both high ornamental and economic value. However, the current leading cultivars of Lilium Oriental hybrid are lack of drought and saline-alkaline tolerance thus it is crucial to improve the above properties. MethodBased on four-year subculture and one-year greenhouse culture, the stability of the target gene and changes of the phenotypes and physiological indices were tested for the single copy transformation line L89 and double copy line L31 with the P5CS-F129A gene of Lilium Oriental hybrid 'Sorbonne'. The Southern blot and cDNA detection showed stable inheritance of the target gene. ResultThe results of drought stress treatments demonstrated that the leaves of both transgenic lines contained higher proline content than the common 'Sorbonne', of which L31 contained the highest proline level. Though the relative leaf ion leakage of both transgenic lines and the common 'Sorbonne' rose in the drought stress process, the transgenic lines showed lower relative leaf ion leakage than the common 'Sorbonne'. After the second watering, the relative leaf ion leakage of both transgenic lines recovered to normal level, while the common 'Sorbonne' didn't. In the aspect of phenotype, both L89 and L31 grew well after the second watering, showing no obvious damage on growth, while the common 'Sorbonne' showed severe leaf etiolation and growth retardation. ConclusionThe above research indicated that the P5CS-F129A transgenic gene lines possessed stronger drought tolerance which would be significant to the cultivation of new cultivars of stress-tolerant lily.
2018, 40(2): 106-113.
DOI: 10.13332/j.1000-1522.20170405
Abstract：
ObjectiveIn general, lot-sizing planning (LSP) is the basis of master production schedule and material requirements planning. Obviously, optimization of LSP is the key to save cost and materials. At present, bulk-production mode is widely adopted in wood-based panel industries. For arranging the productive task, the detail planning needs to be made in advance. However, the scheduled planning usually needs to be re-planned to cope with the change of market requirement dynamically. For this reason, an improved particle swarm optimization (PSO) and a kind of rolling horizon planning (RHP) method are proposed to solve the LSP problem of wood-based panels in this paper. MethodFirstly, according to the characters of production process, a series of decision variables and constrains were determined, and then, a mathematical mixed integer decision method was built for LSP problem. Secondly, an improved PSO algorithm was designed by reducing the dimension of the solution space. At last, with RHP method, the improved PSO algorithm was used to solve a series of sub-LSP problems repeatedly. A simulation example was designed to verify the performance of the LSP model and improve PSO algorithm. ResultAccording to the simulation results, to a wood-based panel production line with an annual output of 100 000 m3, when the planning horizon and total planning period were set to 3 months and 12 months respectively, 1.8% production cost could be saved through RHP method and the improved PSO approach. In addition, to the same model with production capacity constrains, the production cost could be reduced by 0.9%. ConclusionRHP is an efficient way to make lot-sizing planning of wood-based panel. The important advantage of RHP is that the production schedule could be adjusted with the changing market requirement dynamically. Due to the NP-hard of RHP, the intelligent swarm optimizations could solve these problems with an acceptable period of time. In addition, future research will focus on the model of LSP with actual constrains and the algorithms of intelligent swarm optimization.
2018, 40(2): 114-120.
DOI: 10.13332/j.1000-1522.20170366
Abstract：
ObjectiveThe condition of preparation of xylo-oligosaccharide (XOS) from sugarcane bagasse with enzymatic hydrolysis was investigated. In this study, the preparation efficiency of xylo-oligosaccharide was improved by NaOH-ethanol pretreatment. MethodFirstly, the chemical composition of the sugarcane bagasse before and after pretreatment was characterized, and the effect of pretreatment on the components of the raw material was determined. Secondly, the wettability and physical structure of substrates were characterized by contact angle analysis and X-ray diffraction (XRD). Finally, in order to compare the effects of different pretreatments on the mass concentration of XOS with enzymatic hydrolysis, the enzymatic hydrolysate was harvested and analyzed by high performance liquid chromatography (HPLC). ResultCharacterization results confirmed that optimal pretreatment condition was 10 g/L NaOH-ethanol (50% v/v ethanol) pretreatment. Under this pretreatment condition, a large amount of lignin was removed and the removal rate of lignin could reach 78.10%. Moreover, the pretreatment could effectively improve the hydrophilicity of raw materials, decreased the contact angle from 61.5° to 55.4°, and also increased the crystallinity of lignocellulose from 28.6% to 32.3%.The results showed that the highest XOS mass concentration was 1.85 g/L after 10 g/L NaOH-ethanol pretreatment, which was 122.89% higher than that of untreated sugarcane bagasse (0.83 g/L). ConclusionIn the process of XOS preparation from sugarcane bagasse, enzymatic hydrolysis was an efficient way to achieve the conversion from hemicellulose to XOS. NaOH-ethanol pretreatment can effectively increase the efficiency of enzymatic hydrolysis and promote the preparation of XOS.
