Purple Alfalfa Research Articles

Detection of protein content in alfalfa using visible/ near-infrared spectroscopy technology

In this study, a quantitative model was developed using near-infrared spectroscopy to analyze protein content in dried purple alfalfa, employing preprocessing methods (SG, SNV, MSC, FD) and variable selection algorithms (CARS, IRIV) to optimize spectra. Models using ELM, PLSR, SVM, and LSTM were tested; the MSC-CARS-PLSR-SVM model achieved the highest accuracy, with a calibration determination coefficient (R²) of 0.9982 and root mean square error (RMSE) of 0.1088, and a prediction R² of 0.9645 with RMSE of 0.5230, offering a precise and reliable method for protein content prediction.

Manifestation of Valuable Selective Traits in Alfalfa Collection Samples

The paper presents the results of the manifestation and study of alfalfa in a collection seed plot according to the main valuable selective traits, such as leafiness, susceptibility to diseases, the productivity of green mass and seeds, as well as chemical composition and nutritional value. The study aims to identify promising collection varieties for selection from two types of alfalfa, namely variegated alfalfa (M. Varia Mart.) and purple alfalfa (Medicago sativa L.). Field and laboratory methods were used in the study. The laying of seed plots, the assessment of economically valuable traits, and the accounting of productivity were carried out according to the methods of the All-Russian Research Institute of Plant Industry (VIR) named after N. I. Vavilov, the All-Russian Fodder Research Institute named after V.R. Williams and State Crop Variety Testing of the Republic of Kazakhstan. A comprehensive assessment of the collection material for the chemical composition of fodder was carried out in the laboratory. The experiments were performed at the station of the “Kazakh Scientific Research Institute of Agriculture and Plant Growing” LLP. 134 varieties of alfalfa, namely purple alfalfa (M. sativa L.) and variegated alfalfa (M. varia Mart.) of Kazakh and foreign selection from 18 countries of the world were involved in the study. As a result, productive samples by plant height were identified in the material from Italy (k-5677), Russia (k-31885), Kazakhstan (k-6021); productive samples by leafiness were identified in the material from Russia (k-45479), Kazakhstan (k-61324), Italy (k-5677) and productive samples by complex resistance to diseases (yellow leaf spot, brown leaf spot, rust stain) were identified in the material received from Kyrgyzstan (k-6238), Uzbekistan (k-21634) and Italy (k-5975). By harvesting green mass, the following samples were isolated on average over three years: From Uzbekistan (k-267), France (k-315), and Ukraine (k-454). By seed yield, the highest indicator was observed in a sample from France (k-315). The crude protein content was higher in the second cutting. High indicators were observed in samples from Kazakhstan (k-246, 22.6%) and Russia (k-322, 22.3%).

Assessing soil water recovery after converting planted shrubs and grass to natural grass in the northern Loess Plateau of China

The Chinese Loess Plateau (CLP) is prone to adverse effects from drought, especially the widespread creation of a dried soil layer (DSL), a problem intensified by revegetation under the Grain for Green Program. Using 13-year soil moisture (SM) data, we compared soil water consumption by planted shrubs (Korshinsk peashrub, KOP), planted grass (purple alfalfa, ALF), and natural grass (NAG) from 2004 to 2016 in the CLP. To assess the soil water recovery processes, long-term (30 years) SM dynamics were simulated using the simultaneous heat and water (SHAW) model based on field data and local meteorological data under two scenarios (A: converting KOP to NAG and B: converting ALF to NAG). The results showed that the decline rates of SM in 1–4 m profiles for NAG (24.0–29.8%) were much lower than those for KOP (47.6–51.4%) and ALF (48.8–50.2%) during the 13-year growth period. Modelling SM dynamics at depths of 1–4 m for 30 years showed that SM gradually increased and that the DSL prevalence could be reduced under scenarios A and B. The complete elimination of DSL requires at least 6 years at 1–4 m under scenario A, 13 years at 2–4 m, and 22 years at 1–2 m under scenario B. Soil water restored to local stable soil water levels requires approximately 19, 13, and 15 years in the 1–2 m, 2–3 m, and 3–4 m profiles, respectively, under scenario A. Soil water recovery will take approximately 28 years in the 2–3 m profile and 27 years in the 3–4 m profile under scenario B. Our results enhance the understanding of the soil water depletion and recovery processes under different vegetation types and can could be used to provide scientific guidance for sustainable ecological restoration in the CLP.

Binary plantings as a factor of reducing the technogenic load of agrocenosis

The results of research conducted by Voronezh State Agrarian University to determine the effect of binary sunflower plantings in combination with postharvest sideration on the content of plant residues in the soil, on the number of soil microorganisms, on the dynamics of detritus, sunflower infestation and yield are presented. The positive effects of the studied complex of biological function was well established to increase the content of organic matter sources in soil (by 4.64 of 5.67 t/ha), contributing to the increase in the content in the soil detritus (4.7 and 9.9%) on the growth of soil microorganisms, which in combination with the reduction of planting infestation (by 9-18 pcs/m2) has led to significantly higher yields of sunflower (0.18-0.51 in t/ha) compared with the traditional technology of cultivation. As binary components of sunflower, it is recommended to use perennial legumes of yellow melilot and purple alfalfa, and oil radish as a postharvest sideral crop.

Enhanced Saccharification of Purple Alfalfa via Sequential Pretreatment with Acidified Ethylene Glycol and Urea/NaOH

Purple Alfalfa is an inexpensive, abundant, readily available lignocellulosic material. This work was attempted to develop an efficient combination pretreatment by sequential HClO4–ethyl glycol–H2O (1.2:88.8:10, w/w/w) extraction at 130 °C in 0.5 h and urea/NaOH (urea 12 wt%, NaOH 7 wt%) soaking at −20 °C for 0.5 h for the pretreatment of purple alfalfa. The porosity, morphology, and crystallinity of pretreated purple alfalfa were characterized with SEM, FM, XRD, and FTIR. This combination pretreatment had a significant influence on hemicellulose removal and delignification. The above changes could enhance cellulose accessibility to enzymes and improve the enzymatic digestibility of cellulose. High yields of reducing sugars from pretreated purple alfalfa were obtained at 93.4%. In summary, this combination pretreatment has high potential application in the future.

Analysis of individual biologically active compounds from root crop extracts of purple alfalfa (medicago sativa) in vitro

The authors selected the parameters for obtaining root cultures in vitro Medicago sativa. The number of cell culture lines studied is 15. The duration of the growth cycle is less than 50 days. The number of processed explants is 75. The growth characteristics of root cultures of in vitro purple alfalfa (Medicago sativa) were studied. The growth index for the dry biomass of the in vitro root culture of alfalfa was 31. A qualitative and quantitative analysis of the composition of BAS in the biomass of the obtained root cultures of in vitro alfalfa (Medicago sativa) was carried out. Unique biologically active substances (not previously described for alfalfa) were identified.): apigenin, naringenin, myricetin, chrysoeriol, coumestrol, and scopoletin. Rational parameters of isolation of individual BAS from the extract of root cultures of in vitro alfalfa (Medicago sativa) were selected. The degree of extraction of individual BAS is 80%. Methods of purification of individual BAS Medicago sativa have been developed. The degree of purification of individual BAS is 95%.

Ecosystem‐scale carbon allocation among different land uses: implications for carbon stocks in the Yellow River Delta

AbstractThe reclamation area of the Chinese Yellow River Delta (YRD) has experienced frequent land use changes in recent decades. The consequence of such land use changes on the stocks and allocation of ecosystem‐scale carbon is not known. Here, we assessed carbon stocks and allocation of four representative land uses in the YRD area: (1) purple alfalfa (LAL), (2) reed and Aeluropus littoralis (RAE), (3) cotton (ECO), and (4) Chinese tamarisk (CTA). The results showed that the overall carbon stocks, and carbon stocks of aboveground, litter, roots, and soil were notably different among different land uses. The native CTA land had the largest overall carbon stock (belowground and aboveground) and had the strongest potential to allocate the carbon to the soil carbon pool (95.72%), followed by the natural grassland (RAE). Alfalfa grassland (LAL) also had a large carbon stock due to its large aboveground biomass, litter, and roots, but the relative allocation proportion of soil carbon stock was lower than that of the other land uses examined. Cotton (ECO) had the lowest soil carbon and total carbon stocks among four land uses. In combining our data on the carbon pool with changes of land use in the YRD area, we argued that land reclamation in the YRD area was likely to turn this area from a carbon sink to carbon source with the release of soil organic carbon. Therefore, cautions should be taken to reduce carbon release, if the reclaimed land be used to plant crops.

Camponotus japonicus ant mounds indirectly accelerate leaf litter decomposition by altering soil temperature and moisture

As ecosystem engineers, soil-inhabiting ants can influence soil properties in different ways. However, limited attention has been directed toward the role of Camponotus japonicus on litter decomposition in the Loess Plateau. This study quantified the impact of C. japonicus mounds on soil evaporation, temperature and litter decomposition. The distribution and physical properties of C. japonicus mounds in four slopes (61 m × 5 m) under different vegetation types [Korshinsk peashrub (Caragana korshinskii K.), KOP; purple alfalfa (Medicago sativa L.), ALF; natural fallow, NAF; and millet, MIL] were studied. The density of ant mounds in grass and shrublands was considerably higher than that in croplands. Farming activities and intense soil erosion in the crop slope could play a negative role in mound density. On average, half-ellipsoid ant mounds were 2.48 cm in height and 755 cm2 in basal area with 0.75 g/cm3 bulk density. The size distribution of the ant mounds was as follows: 2–3 (6.9%), 1–2 (27.3%), 0.5–1 (16.9%), 0.28–0.5 (18.2%) and <0.28 mm (30.7%). Porous ant mounds that covered the leaf litter of ALF reduced soil evaporation, increased soil temperature and indirectly accelerated leaf litter decomposition. Concentrations of soil organic matter (SOC), total N, ammonium N, nitrate N, available P and available K were higher in soil under ant mounds than those in surrounding soil under KOP, ALF and NAF. High soil moisture and temperature in the leaf litter and enhanced contact area between the soil particles and the leaf litter promoted litter decomposition and contributed to the formation of a ‘fertile island’. These findings may enrich our understanding on the effects of ant activity on soil ecosystems in semiarid areas.

Relative contribution of root physical enlacing and biochemistrical exudates to soil erosion resistance in the Loess soil

Plant roots significantly affect soil erosion, while few works have pursued why root-penetrated soil obtained higher soil erosion resistance as compared with plain soil. For the purpose to investigate the relative contribution of root physical enlacing (root net-link and root-soil bond functions) and root biochemistrical exudates to soil erosion resistance. This study selected Purple alfalfa root- and designed root-penetrated Loess soil as study object, and subjected to flow scouring. The results showed that roots could significantly ameliorate soil properties, especially for soil enzymes. Root physical enlacing is the main reason, accounting for 77.7–82.0% of the root total effect in strengthening soil erosion resistance. And of this total, the relative contribution ratio of net-link and soil-root bond functions to soil erosion resistance was 0.71:0.29, averagely. Root surface area density could effectively reflect root physical enlacing effect. This kind of study may provide theoretical explanations forthe root reinforcement in the flow-induced erosion regions.

Application of X‐ray tomography to quantify macropore characteristics of loess soil under two perennial plants

SummaryWith the advent of large‐scale restoration of vegetation in the Loess Plateau, northwest China, there has been an increase in concern about the suitability of loess soil to support permanent vegetation cover. The quantification of soil macropore characteristics could be critical in determining the architecture and hydrological processes of loess soil on the plateau. In this research, we compared the effects of Purple alfalfa (Medicago sativa L.) and Korshinsk peashrub (Caragana korshinskii K.) on the macropore characteristics of a soil profile on the plateau with computed tomography (CT). To achieve this, undisturbed cores of soil were excavated from beneath purple alfalfa (ALF), 22‐year‐old Korshinsk peashrub (KOP22) and 40‐year‐old Korshinsk peashrub (KOP40) vegetation types in the Liudaogou watershed for evaluation. The soil macropore characteristics (including macroporosity, largest pore area, amounts of macropores, circularity, surface area density, branch density, junction density and connectivity) were determined with image analysis software. Soil under KOP22 and KOP40 treatments had approximately the same amounts of macropores (17 per 6359‐mm2 area), which was three times greater than those under ALF plants. Macroporosity ratios of soil under KOP22 and KOP40 plants to that under ALF plants were 2.3 and 3.6, respectively. Compared with KOP22, KOP40 had a larger macroporosity and the largest pore area at the 100–300‐mm soil depth. The KOP plants, in particular KOP40, apparently improved the macropore network structure of the soil more than ALF. However, the macropores under ALF were much rounder at the 100–300‐mm soil depth than those under the other two plants. There was no correlation between macropore characteristics and organic matter content of the soil at 100–400‐mm depth. Nevertheless, macroporosity was strongly correlated with the largest pore area. The findings of this research are critical for developing strategies for the restoration of vegetation in the Loess Plateau through improvement of the hydrological process of loess soil.Highlights We examined macropore characteristics of loess soil on the Loess Plateau in China. We determined the effects of different plants on soil macropore characteristics. Soil under Korshinsk peashrub had better macropore structure than that under Purple alfalfa. Long‐term recovery of KOP benefits the macropore structure most on the northern Loess Plateau.

Effect of root architecture on structural stability and erodibility of topsoils during concentrated flow in hilly Loess Plateau

Traditional vegetation techniques for the control of concentrated flow erosion are widely recognized, whereas only a few studies have experimentally investigated the impacts of belowground roots on the erodibility of topsoils in semi-arid areas. To quantify the effects of root architectures on soil erodibility and its relevant structural properties, simulated flow experiments were conducted at six-week intervals from 18 July to 20 October in 2012 in the hilly Loess Plateau. Five treatments were: 1) bare (control), 2) purple alfalfa (Medicago sativa), representing tap roots (T), 3) switchgrass (Panicum virgatum), representing fibrous roots (F), 4) purple alfalfa and switchgrass, representing both tap and fibrous roots (T + F), and 5) natural recovery (N). For each treatment, soil structural properties and root characteristics were measured at an interval of six weeks. Soil anti-scouribility was calculated. Results showed that grass planting slightly reduced soil bulk density, but increased soil aggregate content by 19.1%, 10.6%, 28.5%, and 41.2% in the treatments T, F, T + F, and N, respectively. Soil shear strength (cohesion and angle of internal friction (φ)) significantly increased after the grass was planted. As roots grew, soil cohesion increased by 115.2%–135.5%, while soil disintegration rate decreased by 39.0%–58.1% in the 21th week compared with the recorded value in the 9th week. Meanwhile, root density and root surface area density increased by 64.0%–104.7% and 75.9%–157.1%, respectively. No significant differences in soil anti-scouribility were observed between the treatments of T and F or of T + F and N, but the treatments of T + F and N performed more effectively than T or F treatment alone in retarding concentrated flow. Soil aggregation and root surface-area density explained the observed soil anti-scouribility during concentrated flow well for the different treatments. This result proved that the restoration of natural vegetation might be the most appropriate strategy in soil reinforcement in the hilly Loess Plateau.

Dynamics of deep soil moisture in response to vegetational restoration on the Loess Plateau of China

The limitation of soil water in semiarid regions restricts the formation of a good cover of vegetation. The Loess Plateau in China, well known for its severe soil erosion, has a thick loessial soil that holds substantial volumes of water and provides the basis of a sustainable restoration of vegetation. Our limited understanding of the dynamics of deep soil moisture, however, could lead to the mismanagement of soil-water resources or could even misguide the policies of vegetational reconstruction. To evaluate the temporal response of deep soil moisture in different types of revegetation, we observed soil moisture to a depth of 340. cm in four plots, planted with Korshinsk peashrub (KOP), purple alfalfa (ALF), native plants (natural fallow, NAF), and millet (MIL), on 15 measurement events from 2010 to 2012. Our analysis provided four main conclusions. (1) The quantitative difference of potential evapotranspiration and actual precipitation resulted in natural deficits of soil moisture. The dynamics of deep soil moisture, however, were mainly dominated by the type of vegetation. Deep soils in plots of KOP and ALF became drier than the soil in plots of NAF and MIL. (2) Deep soil moisture in KOP and ALF was weakly variable. Correlations of time series of soil moisture between the upper and lower layers tended not to be significant. Dried soil layer, a special hydrological phenomenon, had formed in the plots. (3) The correlation between variances of soil moisture and the corresponding mean values were not always significantly positive due to the influence of vegetational type, observational depth, and date. (4) Fallow may be the best cover for achieving adequate hydrological sustainability of the soil. These results are expected to help improve the understanding of the response of deep soil moisture to vegetational restoration and to provide insight into the dynamics of deep soil moisture influenced by vegetation on loessial slopes.

Response of soil CO2 efflux to water addition in temperate semiarid grassland in northern China: the importance of water availability and species composition

Knowledge of the effects of water addition and the composition of plant species on soil CO2 efflux (SCE) and its temperature sensitivity (Q10) in temperate semiarid grassland is essential for understanding carbon (C) cycles and for evaluating future C balance. Our objective was to examine the seasonal variability of SCE and its sensitivity to temperature in response to water addition in four grasslands on the northern Loess Plateau. SCE was measured during the growing seasons (April–October) in 2010 and 2011 in the four grasslands dominated by different species: purple alfalfa (ALF), bunge needlegrass (BNE), degraded alfalfa (DALF), and fallow land for the recovery of natural vegetation (NAF), in two treatments: water addition (50 mm year−1) and a control. Water addition consistently increased mean seasonal SCE by 8.4–33.8 % across the four communities, attributable to enhanced plant growth, root and microbial activities, and respiration. The magnitudes of the positive effects, however, varied with plant community and measuring period. Soil temperature was primarily responsible for the seasonal changes in SCE in both the control (37–63 %) and the watered (40–75 %) plots. The addition of water increased the Q10 of SCE by 11.0 %, 14.4 %, and 13.4 % for ALF, DALF, and NAF, respectively, but had no significant effect on the Q10 for BNE. We therefore conclude that water addition can significantly increase SCE and may stimulate the sensitivity to temperature in semiarid grassland. The composition of plant species may regulate the dependence of SCE on water and temperature.

Soil CO2 efflux in response to the addition of water and fertilizer in temperate semiarid grassland in northern China

Knowledge about the effects of water and fertilizer on soil CO2 efflux (SCE) and Q (10) is essential for understanding carbon (C) cycles and for evaluating future global C balance. A two-year field experiment was conducted to determine the effects of water, fertilizer, and temperature on SCE in semiarid grassland in northern China. SCE, as well as environmental factors was measured in two grasslands, one with bunge needlegrass (BNE, Stipa bungeana) and one with purple alfalfa (ALF, Medicago sativa), with four treatments: CK (unwatered and unfertilized); W (50 mm water addition yr(-1)); F (50 kg phosphorus (P) fertilizer ha(-1) yr(-1) for ALF, 100 kg nitrogen (N) + 50 kg P fertilizer ha(-1) yr(-1) for BNE); and W + F. During the 11-month experimental period from July 2010 to October 2011, the addition of water consistently stimulated mean SCE in BNE and ALF, and the positive effects were relatively stronger during dry seasons. P fertilization consistently enhanced SCE in ALF, and the positive effect was strongly dependent on the availability of soil water. The effects of N plus P fertilization on SCE in BNE varied seasonally from significant increases to small reductions to no response. Water addition increased the Q (10) of SCE in ALF by 11 % but had no effect in BNE. Fertilization, however, reduced the Q (10) of SCE by 21 % and 13 % for BNE and ALF, respectively. Models that rely only on Q (10) underestimated the emissions of soil CO2 by 8-15 % at the study site, which was mediated by species and treatment. Responses of SCE and its temperature sensitivity to water and fertilizer may vary with species and depend on the period of measurement. Models of SCE need to incorporate the availability of ecosystemic water and nutrients, as well as species, and incorporate different environmental factors when determining the impact of water, nutrients, and species on SCE.

Spatial pattern of soil moisture and its temporal stability within profiles on a loessial slope in northwestern China

Summary Temporal stability of spatial distributions of soil moisture are usually observed after repeated surveys of soil moisture across an area. To understand how temporal stability of soil moisture varied with soil depth under the combined influences of vegetation and local topography, we collected soil moisture data at intervals of 10 cm within 1-m profiles on a loessial slope in China in four plots (61 m × 5 m) under different types of vegetation (Korshinsk peashrub, KOP; purple alfalfa, ALF; natural fallow, NAF; millet, MIL). Measurements of soil water content were made by neutron probes on 15 occasions between 2010 and 2012. Soil moisture distributions in both the vertical and horizontal dimensions were investigated to describe its spatial pattern and to lay the groundwork for better understanding its temporal stability characteristics. The results indicated that: (1) soil moisture presented different vertical but similar horizontal trends in the four plots, with significant correlations of soil moisture occurring primarily among adjacent soil layers irrespective of vegetation types, mostly in soil profiles under KOP and ALF and less frequently in soil profiles under NAF and MIL; (2) based on Spearman rank correlation coefficients, with increasing depth temporal stability generally increased under KOP and MIL, but first increased and then decreased under ALF, and increased after the first three measurements under NAF; (3) based on the relative difference technique, points with extreme moisture tended to remain representative at more depths than did points with average moisture and their time stability increased with increasing soil depth; and (4) the correlation between MRD (mean relative differences) and the wetness index weakened with soil depth. The relationship between SDRD (the standard deviation of MRD) and the wetness index varied nonlinearly with soil depth. Vegetation type, soil depth and the wetness index, in descending order of influence, had significant effects on the temporal stability of soil moisture. Among selected soil properties, saturated hydraulic conductivity, bulk density and soil organic carbon all significantly affected the SDRDs. These observations are expected to add valuable information to the theory of temporal stability and for the practices of soil moisture management.

Temporal stability of soil water storage under four types of revegetation on the northern Loess Plateau of China

Conservation of soil water and restoration of vegetation have long been major subjects of concern on the northern Loess Plateau. Revegetation with species such as Korshinsk peashrub (KOP) and purple alfalfa (ALF), as well as with natural revegetation of fallow areas (NAF) have been used extensively. This paper examines the temporal stability of soil water storage (SWS) under these different revegetation types, including under millet (MIL) crops for comparison, grown in adjacent plots on a hillslope intending to provide information relevant to the strategic guidance of revegetation and soil water management practices. SWS was measured at 10-cm intervals in the soil profile to a depth of one meter using a neutron probe on 11 occasions between 2010 and 2011. The results indicated that: (1) time-averaged SWS relative to MIL decreased in the order of KOP (49.4mm), ALF (32.4mm) and NAF (14.9mm) implying that shortages of soil water were induced largely by revegetation and were affected by the plant species. (2) Frequency distributions showed that points with probabilities of 0.5 were not stable between extreme soil water conditions; however, this result might be mitigated or avoided by increasing the sampling density and/or conducting measurement over a longer period. (3) Based on relative difference analysis, the most stable data points underestimated the mean SWS of the plots but were still valuable for precisely estimating the mean SWS of the experimental plot; in addition, among methods for estimating the plot average using representative points, directly using the value of relative difference or their standard deviation, or an index of temporal stability or the mean absolute bias error, no one method consistently performed better than another. (4) ALF presented the most temporally stable patterns among all types of revegetation tested, and vegetation cover and aboveground biomass were the main factors affecting SWS temporal stability. (5) Temporally stable points were located at the mid-slope of the plots. In conclusion, when temporal stability theory was applied to sloping lands mid-slope sampling is likely to give the best results but vegetation characteristics, and in particular vegetation cover should be highlighted.

Soil organic carbon and total nitrogen as affected by vegetation types in Northern Loess Plateau of China

One of the most fragile areas in the China Loess Plateau, is the transitional belt that is subjected to wind and water erosion. The transitional belt accounts for about 30% of the Loess Plateau area. To reduce soil degradation in the Loess Plateau, the Chinese government initiated a state-funded vegetation restoration project in 1999. The effectiveness of this project on transitional belt soils is unknown. The objective of this study is to determine the effects of four dominant vegetation types on soil organic carbon (SOC) and nitrogen (N) in a selected catchment within the transitional belt. Korshinsk Peashrub (KOP), purple alfalfa (ALF), and natural fallow (NAF) were selected as vegetation restoration types because they have been used widely to remedy soil degradation. The fourth vegetation type selected was millet (MIL) because it has been an important crop in the region. In 2004, four 61 × 5 m plots were established on 12° slope land. The plots were parallel and separated by 80 cm. Based upon soil samples collected in August of 2007, there were large variations in the distributions and stocks of SOC and N across the four vegetation types. Compared with MIL, KOP significantly increased the concentration and stock of SOC and total nitrogen (TN) in 0–100 cm soil profiles, while ALF and NAF were not significantly different. The distributions of SOC and TN concentrations and stocks of KOP, ALF and NAF were relatively uniform along a hillslope, while there was an increasing trend along the hillslope in MIL. This result suggests that ALF and NAF would be beneficial in SOC and TN sequestration over a long-term because of their ability to reduce the loss of SOC and TN by soil erosion. We also found that both vegetation types and hillslope position had no significant effects on C:N ratio. Our study demonstrated that improvements of SOC and TN stocks in the transitional belt could be made through well managed vegetation restoration measures.

Effects of NaCl, Na2SO4, and mannitol on storage lipid mobilization in the cotyledons and roots of purple alfalfa seedlings

The effects of NaCl, Na2SO4, and mannitol on mobilization of storage lipids in the cotyledon mesophyll and root meristem cells during the germination of purple alfalfa (Medicago sativa L.) seeds were studied using the transmission electron microscopy technique. The ultrastructural analysis showed that the number and shape of specific organelles, oleosomes, depended on the osmotic effects of a salt used. In control seedlings grown on distilled water, lipid mobilization in roots terminated by the 4th day, and in cotyledons, only by the 8th day. The disruptions in the storage lipid mobilization in the treated seedlings were specific and depended on the stress agent used, the osmotic pressure induced by this agent, as well as on the tissue type. The presence of a great number of oleosomes in the cytoplasm of cells subjected to osmotic stress, in contrast to the control ones, demonstrated the inhibition of mobilization processes. All concentrations of Na2SO4 and mannitol suppressed lipid mobilization in the cotyledons and roots. At the same time, NaCl markedly suppressed this process in the root cells only at a higher osmotic pressure of the solution. The results obtained suggest that the cytological analysis of cotyledon storage-lipid mobilization can tentatively assess the resistance of dicotyledonous plants to abiotic stresses.

서양금혼초(Hypochaeris radicata L.)의 수용추출물이 사료작물에 미치는 allelopathy 효과

서양금혼초(Hypochaeris radicata Linne)에 함유되어있는 화학물질이 사료작물의 미치는 allelopathy효과를 구명하기 위하여 본 실험을 실시하였다 서양금혼초에 함유되어 있는 allelochemicals 물질을 HPLC에 의해 성분 분석한 결과 계절적, 부위별로 차이가 있었으나 <TEX>$\rho$</TEX>-hydroxybenzoic acid, chlorogenic acid, catechin, caffeic acid, syringic acid, salicylic acid, <TEX>$\rho$</TEX>-coumaric acid, ferulic acid, naringin, hesperidin, myricetin, krans-cinnamic acid, quercetin, naringenin 등 14 종류의 phenolic compounds 성분을 확인하였고 caffeic acid, ferulic acid, naringenin 3종류는 공통으로 함유하고 있는 것으로 분석되었다. 5월에는 일, 7월에는 꽃과 뿌리에서 많은 양의 phenolic acids가 함유되어있고 특히 뿌리에 sali-cylic acid <TEX>$2085.6{\mu}g/g$</TEX>,와 quercetin <TEX>$1522.0[\mu}g/g$</TEX>,로 함량이 높았다. 서양금혼초 수용성 추출액으로 처리한 사료작물의 생장을 조사한 결과 품종에 따라 처리구와 대조구의 값이 같은 경우도 있으나 모든 조사 항목에서 대조구 보다 처리 값이 낮아 사료작물의 생장이 억제 된 것이 확인되었고 처리농도가 높을수록 강한 억제효과를 나타내었다. 수량의 변화를 조사한 결과 사료작물 품종에 따라 차이가 있으나 전체적으로 억제효과를 나타내었으며 처리농도가 높을수록 강한 억제효과를 나타내었다. 이러한 결과 서양금혼초는 사료작물에 대한 allelopathy 효과가 있음을 밝혀냈다. 특히 화본과 사료작물의 경우 italian ryegrass, 콩과 사료작물의 경우는 purple alfalfa가 생장억제효과가 높게 나타났다. This experiment was performed to examine the allelopathy effect of allelochemical substance on the crop plants. According to the experiment of the allelochemical substances in Hypochaeris radicata by HPLC, there are the differences at each part of plants. However, it is ascertained that there are 14 kinds of phenolic compounds ingredients that are <TEX>$\rho$</TEX>-hydroxybenzoic acid, chlorogenic acid, catechin, caffeic acid, syringic acid, salicylic acid, <TEX>$\rho$</TEX>-coumaric acid, ferulic acid, naringin, hesperidin, myricetin, trans-cinnamic acid, quercetin and naringenin. The chemicals like caffeic acid, ferulic acid, and naringenin are commonly included. The result of the chemical experiment shows that there are the differences at each season and part of plants. The leaves in May and blossoms and roots in July contain lots of phenolic acids. It is very high contents such as salicylic acid 2085.6 <TEX>${\mu}g/g$</TEX> and quercetin 1522.0 <TEX>${\mu}g/g$</TEX>, especially in roots of plants. The result on the growth of crop plants treated by the aqueous extract of Hypochaeris radicata shows that the value of the control group and the test group are same in some cases. However, because the treat value of test group is towel'than that of control group in all items of the experiment, it is cofirmed that the growth of crop plants was inhibited and that the inhibitory effect was increased as its density of treatment was increased. The result of change in quantity shows that there are the differences at each kind of crop plants, but the inhibitory effect was increased as its concentration of treatment was increase with entire. As results, it is confirmed that H. radicata has the allelopathy effect to the crop plants. Especially the inhibitory effect on growth is high in gramineous crop, italian ryegrass and leguminous crop. purple alfalfa.