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1.
Ecological restoration by Tamarix plants on semi-arid saline lands affects the accumulation, distribution patterns and related mechanisms of soil water content and salinity. In this study, spatio-temporal variations of soil water content and salinity around natural individual Tamarix ramosissima Ledeb. were invetigated in a semi-arid saline region of the upper Yellow River, Northwest China. Specifically, soil water content, electrical conductivity(EC_e), sodium adsorption ratio(SAR_e), and salt ions(including Na~+, K~+, Ca~(2+), Mg~(2+) and SO_4~(2–)) were measured at different soil depths and at different distances from the trunk of T. ramosissima in May, July, and September 2016. The soil water content at the 20–80 cm depth was significantly lower in July and September than in May, indicating that T. ramosissima plants absorb a large amount of water through the roots during the growing period, leading to the decreasing of soil water content in the deep soil layer. At the 0–20 cm depth, there was a salt island effect around individual T. ramosissima, and the EC_e differed significantly inside and outside the canopy of T. ramosissima in May and July. Salt bioaccumulation and stemflow were two major contributing factors to this difference. The SAR_e at the 0–20 cm depth was significantly different inside and outside the canopy of T. ramosissima in the three sampling months. The values of SAR_e at the 60–80 cm depth in May and July were significantly higher than those at the 0–60 cm depth and higher than that at the corresponding depth in September. The distribution of Na~+ in the soil was similar to that of the SAR_e, while the concentrations of K~+, Ca~(2+), and Mg~(2+) showed significant differences among the sampling months and soil depths. Both season and soil depth had highly significant effects on soil water content, EC_e and SAR_e, whereas distance from the trunk of T. ramosissima only significantly affected EC_e. Based on these results, we recommend co-planting of shallow-rooted salt-tolerant species near the Tamarix plants and avoiding planting herbaceous plants inside the canopy of T. ramosissima for afforestation in this semi-arid saline region. The results of this study may provide a reference for appropriate restoration in the semi-arid saline regions of the upper Yellow River.  相似文献   

2.
丛枝菌根真菌(Arbuscular Mycorrhizal Fungi,AMF)对植物抗旱、养分吸收等有重要作用,但在特定环境胁迫下不同生活型植物对AMF的响应存在差异。本文以塔里木河下游荒漠河岸林的优势灌木多枝柽柳(Tamarix ra?mosissima)和常见半灌木疏叶骆驼刺(Alhagi sparsifolia)为研究对象,分析了干旱胁迫处理下(对照组土壤相对含水量为70%±5%、实验组土壤相对含水量为20%±5%)接种AMF(对照组不接菌M-、实验组接菌M+)对多枝柽柳与疏叶骆驼刺混合种植(对照组单一种植)根系生长状况和氮素吸收分配的影响。结果表明:(1)植物遭受干旱胁迫时,多枝柽柳幼苗和疏叶骆驼刺菌根侵染率均降低了,混合种植显著增加了多枝柽柳幼苗的菌根侵染率(P<0.05);(2)干旱胁迫下,混合种植M+处理显著增加了多枝柽柳幼苗的地上、地下生物量;(3)干旱胁迫下,AMF使不同种植模式下两种植物的细根根长和细根表面积均显著增加,使疏叶骆驼刺的比根长显著减小,且混合种植M+处理显著减小了多枝柽柳幼苗的细根比根长;(4)相比单一种植,干旱胁迫下AMF显著增加了混合种植多枝柽柳幼苗的氮摄取量和地上部分氮分配比率。因此,AMF对于干旱胁迫下与疏叶骆驼刺混生的多枝柽柳幼苗的生长和氮素吸收具有明显的补偿作用,能够帮助塔里木河下游多枝柽柳幼苗较好地度过生长脆弱期。  相似文献   

3.
干旱地区的荒漠植被根系发达,其保持岸坡稳定和固土护堤的作用优为重要。在塔里木河流域选取红柳、芦苇和胡杨等典型荒漠植被根系,研究植被根系对塔里木河岸坡坡稳定性的影响,对于促进防治塔里木河水土流失和建设良好生态环境具有重要的现实和理论意义。文中以实测数据和水槽试验结果为基础,运用BSTEM模型,对植被根系对塔里木河岸坡坡稳定性的影响过程进行了模拟。结果表明:(1)在竖直、倾斜、相交三种布置方式下,红柳根系体积密度RVD为8%时,安全系数Fs分别为1.29、1.27及大于1.3,当根系体积密度在8%~28%时,岸坡安全系数全都大于1.3;芦苇和胡杨根系结果也类似,说明随着RVD增大,岸坡安全系数会增大,从而岸坡越稳定;(2)不同根系放置方式对岸坡稳定性影响不同,如RVD为8%时,红柳根系竖直、倾斜和相交放置的安全系数分别提高了33%、30.9%和40.2%,所以提高岸坡稳定性大小次序为:相交﹥竖直﹥倾斜;(3)从根系类型看,提高岸坡安全系数次序为:红柳﹥胡杨﹥芦苇;(4)与无根系相比,有植被根系岸坡稳定性均比无植被根系有一定程度增加,相同植被根系下相交放置提高岸坡安全系数最显著,相同布置方式下红柳根系提升岸坡稳定性最明显。  相似文献   

4.
CHEN Juan 《干旱区科学》2022,14(9):1038-1054
Water is a limiting factor in the restoration and construction of desert steppe. Exploring plant water sources is necessary to understand soil-plant interactions and species coexistence; however, water sources of major plant communities within the desert steppe of Ningxia Hui Autonomous Region, China remain poorly understood. In this study, we analyzed the water uptake of plants in four typical communities: Agropyron mongolicum Keng.; Sophora alopecuroids Linn.; Stipa breviflora Griseb., and Achnatherum splendens (Trin.) Nevski communities. Stable isotopes δD and δ18O in the xylem of plant and soil water at different soil depths were analyzed. An IsoSource model was used to determine the soil depths from which plants obtained water. Results showed that A. mongolicum community obtained water predominantly from 0-20 and 40-80 cm depth, S. alopecuroids community from 0-20 cm depth, S. breviflora community from 0-40 cm depth, and A. splendens community from 0-20 and 80-140 cm depths. S. alopecuroides had a wider range of soil depths for water extraction, i.e., utilizing different water sources depending on habitat, and the plasticity of its water uptake pattern determined its role in different communities. Water source of plants relayed heavily on the distribution of their roots. Competition for soil water exists between different plant life forms in the sierozem habitat (A. mongolicum, S. alopecuroids, and S. breviflora communities), and in the sandy soil habitat (A. splendens community). The use of soil water by A. splendens community is more spatially differentiated, and shrubs and herbs can coexist stably. Under the pattern of extended drought period in the future, sierozem habitat may be more favorable for the formation of a dominant monoculture community type of perennial fibrous plants. In aeolian sandy soil habitat, A. splendens had a strong competitive advantage, and the growth of shallow-rooted plants was easily suppressed.  相似文献   

5.
策勒绿洲前沿两种植物的水分生理生态特征   总被引:20,自引:6,他引:14  
20 0 3年夏季 ,在策勒绿洲前沿地区同一生境条件下 ,研究了骆驼刺 (Alhagisparsifolia)、多枝柽柳(Tamarixramosissima)水势和蒸腾作用的日变化及其与环境因子的关系。结果表明 :在相同土壤水分条件下 ,多枝柽柳的水势低于骆驼刺的水势。多枝柽柳的蒸腾作用与得到充分水分供应的植物一致 ,而骆驼刺则表现为中午限制供水的植物类型。多枝柽柳和骆驼刺气孔导度的变化是影响蒸腾速率最主要的因子 ,环境因子中气温、大气相对湿度与蒸腾速率的相关性最显著 ;有效光合辐射与水势的相关性最高。大气相对湿度与水势呈正相关 ,与蒸腾速率呈负相关。从两种植物表现出的水势和蒸腾作用的特点看 ,多枝柽柳较骆驼刺更适应所处的生境条件  相似文献   

6.
压砂地土壤导水特性空间格局及影响因子   总被引:3,自引:0,他引:3  
采用10 m×10 m网格布点的方式对宁夏压砂田0~10 cm和10~20 cm深度下土壤饱和导水率(Ks)及其相关因素的空间变异规律进行研究。经典统计结果表明:2个采样深度下土壤容重、总孔隙度和毛管孔隙度表现为弱变异,饱和含水量和土壤有机质含量表现为中等变异;0~10 cm深度下K_s表现为中等变异,10~20 cm深度下K_s表现为强变异;10~20 cm深度下土壤各种性质的平均值均大于0~10 cm深度。Pearson相关性分析可知,影响K_s的主要因素是毛管孔隙度,其次为容重、总孔隙度、饱和含水量和有机质含量。地统计结果表明,0~10 cm深度下K_s表现为纯块金效应,主要受随机性因素的影响,10~20 cm深度下K_s主要受结构性因素的影响;在2个采样深度下容重主要受随机因素的影响。从空间分布图可以看出,2个采样深度下K_s和容重存在高度的负相关关系,与饱和含水量、总孔隙度和毛管孔隙度存在高度的正相关关系。  相似文献   

7.
西北干旱区山地—绿洲—荒漠系统信息传递耦合关系   总被引:11,自引:0,他引:11  
在干旱区的山盆体系中,胡杨、柽柳等天然植被的繁衍过程,是对热量、水分、土壤、气候等环境要素综合信息的反馈。太阳辐射量的变化,制约了生物和相关环境要素的分布格局。水资源的形成、转化、消耗过程中,与环境中的土壤、大气及生物发生水力联系,并输送了大量的泥沙、矿物质及无机盐类;地表水、地下水、土壤水、植物需及其相互转化过程中,存在着极其复杂的关系。无论是水分的蒸散、渗漏、运移及植物吸收,还是N、P等矿质元素的循环,都随地理环境的不同而有所不同,土壤微生物在整个过程中,发挥着极其重要的作用,人为的灌溉、开垦、施肥、管理措施,直接给土壤赋以附加信息。各种自然地理要素和人文因素的发展变化,沟通和联系着山地、绿洲及荒漠系统间的复杂关系。  相似文献   

8.
黄土高原藓结皮覆盖土壤导水性能和水流特征   总被引:1,自引:0,他引:1  
生物结皮具有特殊的水文物理性质,为探究其对土壤水分渗透性和水流特征的影响,以黄土高原风沙土和黄绵土上3种典型地表覆盖类型(裸地、藓结皮、藓结皮-草本植物混合)为对象,采用环刀法和染色示踪法对其导水性质与水流特征进行探究。结果表明:藓结皮对2种土壤类型0~5 cm土层土壤理化性质影响较大,与裸地相比土壤容重降低了9.85%~10.00%,土壤黏粒含量增加了1.01~1.29倍,表层有机质含量提高了2.73~3.02倍;藓结皮使0~5 cm土层土壤饱和导水率降低了61.32%~88.89%,而在5~10 cm土层饱和导水率则有明显上升。另外,由于草本植物的影响,藓结皮-草本植物0~5 cm土层与藓结皮土壤相比土壤饱和导水率提高了1.32~6.43倍;黄绵土藓结皮与藓结皮-草本植物的染色面积比均高于裸地,且水分下渗深度增加了10 cm,而风沙土藓结皮与风沙土裸地的染色面积比差异不明显。综上所述,藓结皮和藓结皮-草本植物的存在改变了表层土壤水分渗透性以及水流运动特征和水分下渗深度,影响着黄土高原土壤水分保持和生态恢复。  相似文献   

9.
塔克拉玛干沙漠腹地人工绿地三种灌木的离子吸收特性   总被引:6,自引:1,他引:5  
塔克拉玛干沙漠腹地人工绿地长期使用矿化度 4.0g/L以上的地下水灌溉 ,柽柳、梭梭和沙拐枣三种灌木仍然能够正常生长 ,表现出较强的抗盐特性。通过对三种不同年龄的灌木及其根、茎和凋落物的盐分分析 ,表明 :不同种类和年龄灌木对可溶性离子的吸收特性存在较大的差异 ;同一种灌木不同器官的离子吸收特性差异显著 ,表现出三种灌木在抗盐机理方面不同的生理和生态学特性 ,即 :柽柳从土壤中吸收的大量盐分离子 ,通过叶片的泌盐腺排出体外 ,使植物体内的盐分离子含量保持在相对较低的水平 ,这类植物属于泌盐类植物 ;梭梭能够从外界环境吸收大量的盐分 ,在植物体内储藏 ,并且依靠植物肉质同化枝吸收大量的水分 ,使得植物体内的盐分浓度维持在一定的限度内 ,这类植物属于盐多汁类植物 ;而沙拐枣通过根部运输系统的超滤 ,使得过量的盐被阻止在体外 ,保持植物体内较低的盐分浓度 ,此类植物主动避开盐分 ,属于拒盐类植物  相似文献   

10.
甘肃黄土高原土壤水分预测及旱情预警模型研究   总被引:2,自引:0,他引:2  
2006年天水农业气象试验站在自然状态下进行了土壤水分的消退试验,根据试验数据,揭示了土壤水分的消退规律.结果表明,从最适宜土壤湿度的上限开始,土壤含水量随时间的消退为对数曲线.从最适土壤水分含量的上限到下限需5 d时间,土壤失水速度为13.4 mm/d;从轻旱上限消退至严重干旱需20 d时间,土壤水分散失速度为3.9 mm/d.在此基础上建立了100 cm土层土壤含水量的预测模型及土壤干旱预警模型,经不同降水年型土壤水分实测值的检验表明,土壤含水量预测模型准确率较高,土壤干旱预警模型在预测不同程度的土壤干旱时准确率比较高,有一定实用性.  相似文献   

11.
水分胁迫对柽柳植物可溶性物质的影响   总被引:58,自引:4,他引:54  
甘蒙柽柳(TamarixaustromongolicaNakai)、多枝柽柳(T.ramosisssimaLedeb.)、中国柽柳(T.chinensisLour)短穗柽柳(TlaxaWild.)刚毛柽柳(T.hispidaWild.)密花柽柳(T.arceuthoidsBge.)、甘肃柽柳(T.gansuensisH.Z.Zhang)和短毛柽柳(T.kareliniiBge.)在土壤缓慢水分胁迫  相似文献   

12.
新疆三种类型盐生植物矿质元素含量的特点比较   总被引:2,自引:1,他引:2  
通过比较生长在新疆极端干旱区的三种生态类型的盐生植物 ,即积盐植物 (以盐爪爪为代表 )、泌盐植物(以柽柳为代表 )和避盐植物 (以芦苇为代表 )地上部元素含量特点 ,发现盐爪爪属于Na>K >Ca >Mg型SO2 -4-Cl-盐生植物 ,柽柳属于Ca>Mg >Na>K型Cl--SO2 -4盐生植物 ,芦苇属于Ca >Na >K >Mg型的Cl--SO2 -4型盐生植物。Na、K、Cl-含量以盐爪爪 >柽柳 >芦苇 ,SO2 -4含量以芦苇 >柽柳 >盐爪爪 ,Mg2 + 含量柽柳 >盐爪爪 >芦苇 ,Ca含量为柽柳 >芦苇 >盐爪爪。这三种盐生植物体内元素含量特点与其生长的土壤盐分类型相反  相似文献   

13.

Reports on the dynamics of carbon and nitrogen at different depths in soil profiles usually describe a higher mineralization of both at upper horizons. Nevertheless, under Mediterranean climate, upper soil horizons are strongly affected by drought, especially in summer, and may offer pedoclimatic conditions less favorable to microbial activity than deep soil layers. Therefore, decomposition could be slower in the upper soil layers. To test this hypothesis, mixtures of Medicago sativa ground plants and soil material were incubated in the field, at 5, 20, and 40 cm depth, in nylon mesh bags. Mineralization of carbon and nitrogen was studied for two years. At 5 cm, mineralization of both elements was lower, and no differences were found between 20 and 40 cm. After two years of field incubation, the remaining carbon (as a percentage of the initial content) was 27.95 % +/- 0.88 at 5 cm depth, 19.87% +/- 0.77 at 20 cm, and 18.78 % +/- 1.19 at 40 cm. Mineralization of nitrogen exceeded that of carbon. After two years of field incubation, the remaining nitrogen (as a percentage of the initial content) was 17.62% +/- 3.06 at 5 cm depth, 12.17% +/- 0.94 at 20 cm, and 11.26% +/- 0.99 at 40 cm. The biodegradation rate in upper layers was lower for all biochemical fractions (water-soluble compounds, lipids, polysaccharides, lignin). This contrasts with the usual findings on this topic, but is consistent with our previous results with forest litter samples. Mineralization clearly followed double-exponential kinetics, with a labile and a recalcitrant pool of both carbon and nitrogen. The labile pool of carbon accounted for about 50% of the total initial carbon, whereas that of nitrogen accounted for about 60%. No clear effect of depth on the proportion between the labile and the recalcitrant pool was observed, neither for carbon nor for nitrogen. It was not possible to identify both pools with the biochemical fractions, suggesting that these pools should be interpreted in physical terms (unprotected vs. protected ). No direct effect of depth on the global retention of N was detected.  相似文献   

14.
Seedling emergence of Alopecurus myosuroides Huds., Stellaria media L. (Vill.), Galium aparine L. and wheat (Triticum aestivum L.) was compared at a range of depths of soil cover from 2 to 11 cm. The covering soil was a fertile agricultural soil with 60% clay content which had been sieved into four aggregate sizes. The aggregate sizes used were 26-50 mm. 14-25 mm. 6-13 mm and below 6 mm. Total emergence of all species was reduced with increased depth of sou cover. With A. myosuroides and S. media, total emergence was lowest in fine soil conditions. Alopecurus myosuroides showed a marked interaction whereby response to depth of sowing was least with fine tilth. The time to 50% emergence showed a similar response. With all four species, seedling emergence was slowest at greater depths of sowing and with the finest tilth, the differences tending to increase with increasing depth of sowing. A vert high proportion of the time to 50% emergence was accounted for by the lag time between sowing and the first recorded emergence.  相似文献   

15.
C3 plant Reaumuria soongorica and C4 plant Salsola passerina are super xerophytes and coexist in a mixed community in either isolated or associated growth, and interspecific facilitation occurs in associated growth. In the present study, the root traits including root distribution, root length(RL), root surface area(RSA), root weight(RW) and specific root length(SRL) of both species in two growth forms were investigated to clarify their response to facilitation in associated growth. Six isolated plants of each species, as well as six associated plants similar in size and development were selected during the plant growing season, and their roots were excavated at 0–10, 10–20, 20–30, 30–40 and 40–50 cm soil depths at the end of the growing season. All the roots of each plant were separated into the two categories of fine roots(2 mm diameter) and coarse roots(≥2 mm diameter). Root traits such as RL and RSA in the fine and coarse roots were obtained by the root analyzing system WinRHIZO. Most of the coarse roots in R. soongorica and S. passerina were distributed in the top 10 cm of the soil in both growth forms, whereas the fine roots of the two plant species were found mainly in the 10–20 and 20–30 cm soil depths in isolated growth, respectively. However, the fine roots of both species were mostly overlapped in 10–20 cm soil depth in associated growth. The root/canopy ratios of both species reduced, whereas the ratios of their fine roots to coarse roots in RL increased, and both species had an increased SRL in the fine roots in associated growth. In addition, there was the increase in RL of fine roots and content of root N for S. passerina in associated growth. Taken together, the root growth of S. passerina was facilitated for water and nutrient exploration under the interaction of the overlapped roots in both species in associated growth, and higher SRL allowed both species to more effectively adapt to the infertile soil in the desert ecosystem.  相似文献   

16.
不同土层深度苜蓿断根后对其株高生长的影响   总被引:1,自引:0,他引:1  
对苜蓿进行不同土层深度断根处理,以阻断其不同深层根系对土壤水分的吸收,研究苜蓿地上部分株高生长的反馈特征。结果表明:苜蓿在不同土层断根当年,各深度的断根处理均使苜蓿株高生长受到一定抑制,与对照相比有所降低。不同层次断根的苜蓿在断根当年浅层次断根(20、406、0 cm)受到的水分胁迫较其它处理严重。在断根初期(半个月)与对照呈极显著差异;在收获期株高与对照(26.70 cm)相比,株高分别降低了13.10、12.851、1.30 cm,表现为断根越浅,影响越大。各处理在断根的次年,苜蓿返青期的株高变化曲线十分平缓。收获期断根处理20、402、30 cm的苜蓿株高比对照(37.96 cm)分别降低了5.08、5.34、5.30 cm,较对照差异性极显著(P0.01),各断根处理较断根当年株高的生长量均有显著提高。两年的数据表明浅层次断根处理的株高生长受到水分胁迫较深层断根处理严重。不同土层断根处理的株高生长受抑制程度为:浅层次处理中层次处理深层次处理。  相似文献   

17.
土壤水分胁迫对柽柳体内膜保护酶及膜脂过氧化的影响   总被引:58,自引:4,他引:54  
甘蒙柽柳(Tamarix austrmongolica Nakai)、多枝柽柳(T.ramosissima Ledeb.)、中国柽柳(T.chinensis Lour.)、短穗柽柳(T.Laxa Wild.)、刚毛柽柳(T.hispida Wild.)、密花柽柳(T.arceuthoides Beg.)、甘肃柽柳(T.gansuensis H.Z.Zhang.)和短毛柽柳(T.karelinii Bge.)在土壤水分胁迫条件下,膜保护酶超氧化物歧化酶(SOD)、过氧化物酶(POD)活性在整个干旱处理过程中先上升而后下降,8种柽柳SOD、POD活性达最高的处理时间种间存在差异。膜脂过氧化产物丙二醛(MDA)含量在干旱处理中没有持续增加,其变化呈双峰型。  相似文献   

18.
荒漠结皮对土壤水分状况的影响   总被引:22,自引:1,他引:21  
本研究针对鄂尔多斯沙地生物结皮进行调查 ,利用人工喷水模拟降雨分析结皮对土壤入渗性能的影响。研究表明 :生物结皮能显著地降低土壤水分的入渗速率。在去掉结皮时 ,表层下 5 cm处的土壤含水量在 1 0分钟时即开始显著增加 ,而有结皮时 ,此处的含水量则在 1 5分钟时才开始显著增加。利用圆盘入渗仪测定有结皮和无结皮条件下的土壤饱和导水率表明 :固定沙丘间地有生物结皮的土壤饱和导水率范围是 :2 9.1 0 - 82 .2 1 mm/ h;半固定沙丘有微弱结皮时饱和导水率为 1 43.5 4 - 2 30 .2 5 ;去掉结皮后土壤的饱和导水率可显著上升数倍 ,无结皮的流沙的饱和导水率最高。  相似文献   

19.
Glasshouse experiments were conducted from March to July 2003 to determine the effects of sowing depth, and the time, duration, and depth of flooding on the emergence, survival, and growth of Fimbristylis miliacea (L.) Vahl. The treatments that were evaluated in the first experiment were three seeding depths (0, 0.5, and 1.0 cm), while in the second experiment, three flooding depths (saturated soil with no standing water and soil with water depths of 5 and 10 cm) and three flooding durations (7, 14, and 21 days from sowing) were evaluated. In the third experiment, three flooding depths (saturated soil with no standing water, and soil with water depths of 5 and 10 cm) and four flooding regimes (7, 14, 21 or 28 days after sowing [DAS]) were evaluated. Surface seeding gave the highest emergence rate compared to the 0.5 cm and 1.0 cm soil depths. A significantly higher emergence rate was recorded with the saturated conditions than with the flooded conditions. A flooding duration of ≥ 14 days showed a clear trend of reduced emergence with increasing flooding depth. A significantly higher survival rate, plant height, root length, number of leaves, and dry matter were recorded at soil saturation followed by the 5 cm and 10 cm flooding depths when flooding was simulated at 7 and 14 DAS. When the flooding was delayed to 21 and 28 DAS, the 10 cm flooding depth was required to suppress this weed. The results provide sufficient evidence to confirm that from deeper seed burial (1 cm sowing depth), flooding depths of ≥ 5 cm of durations of 14 and 21 days and at the onset of flooding within 14 DAS were effective in suppressing the emergence and growth of F. miliacea .  相似文献   

20.
新疆柽柳属植物(Tamarix L.)的分布与群落相似性聚类分析   总被引:13,自引:7,他引:13  
调查研究了新疆境内柽柳属植物的分布与群落类型。在前人工作基础上绘制了新疆柽柳属植物分布图。研究结果表明,地表水是柽柳群落繁衍的关键,地下水是柽柳群落生存的命脉。水是决定和影响柽柳属植物现代地理分布的关键环境因子。依据柽柳群落所处地形地貌、土壤类型和群落景观等环境特征将柽柳群落划分成9种不同的生态类型。依据群落间物种组成的相似性系数对群落进行了聚类分析,揭示了各类落间的内在关联性和演替规律。  相似文献   

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