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81.
草本植物根系对边坡浅层稳定性影响研究 总被引:1,自引:0,他引:1
为研究草本植物根系对边坡浅层稳定性的影响,在假设滑坡体为长方体的条件下,通过对植物根系加固边坡的力学原理进行分析,推导了植物根系对边坡浅层稳定性的安全系数公式,并计算分析了坡度、滑坡体尺寸以及根土面积比对边坡稳定性的影响。结果表明:随着边坡坡度及滑坡体尺寸的增加,边坡的稳定系数将减小。并且,植物护坡的坡体安全系数要大于无防护坡体的安全系数。随着根-土面积比的增大,坡体的稳定系数逐渐增加,说明植物根系能增加边坡的稳定性。 相似文献
82.
83.
本文主要利用三种发根农杆菌A4、15834、R1601诱导苦参产生毛状根,初步为建立苦参的毛状根培养体系提供参考。本实验采用共培养法,考察了不同外植体、菌种、培养时间对苦参毛状根诱导率的影响,并对苦参毛状根中氧化苦参碱进行初步的含量测定。研究结果表明,苦参毛状根的最佳诱导条件是以生长1周的苦参幼芽为外植体,R1601为菌株,添加100μmol/l的乙酰丁香酮,侵染20 min,(25±1)℃暗处诱导,最终测定诱导率最高为27.6%,存活率为45.8%,而苦参毛状根中氧化苦参碱的富集量为1.68mg/g(苦参毛状根干重),未检测到苦参碱。 相似文献
84.
Lingli Yang Naoko H. Miki Naoko Matsuo Guosheng Zhang Linhe Wang Ken Yoshikawa 《农业科学与技术》2014,(3):251-259
duniperus sabina Linnaeus, an evergreen shrub with prostrate life form, can effectively prevent sand moving and is an important tree species for reforestation in semiarid areas of China. It has laterally distributed adventitious roots and a deeply distributed main root system. To detect water movement between the main root system and adventitious roots, we adopted heat pulse sensors using the Heat Ratio Method, a high precision method for measuring low sap flow rates. Two sensors were implanted in each individual in the stem between the main root system and adventitious roots, and another two in lateral stems distal to all the roots. Positive sap flows during nighttime, even under saturated air moisture conditions, were detected only between the main root system and adventitious roots under drought conditions, and the rate of flow increased as drought progressed and decreased or disappeared after rain events. The results demonstrated the existence of water movement from the main root system to adventitious roots, and combined with the high contribution of nighttime sap flow to transpiration (11%-16%) the results indicate that it also involves the process of hydraulic lift, a water movement from moist subsoil to dry surface soils. Integrated water use strategy between the main root system and adventitious roots via the process of hydraulic lift of soil water maximizes water acquisition efficiency from both subsoil water and water from rain pulses on the soil surface; this increases survivability in the water-limited environment of semiarid areas. 相似文献
85.
基于形态参数的水稻根系三维建模及可视化 总被引:5,自引:1,他引:4
构建基于形态特征参数的水稻根系几何模型,实现不同生长条件下水稻根系生长动态的三维可视化。本文通过分析水稻根尖生长随生育进程的变化模式,构建了水稻单根三维显示模型,包括根节点初始位置和生长方向的确定以及根轴的空间模拟等;进一步结合水稻根系拓扑结构,以生长度日(GDD)为驱动因子,建立了水稻根系三维重构模型,包括不定根初始发生时间和位置、不定根初始伸展角度、不定根伸长速率、不定根空间分布模型等;然后在Visual C++环境下,结合可视化显示模块、场景控制模块、人机交互界面和数据库模块等,研制了水稻根系三维可 相似文献
86.
本文利用发根农杆菌A grobacterizum rhizogenes1.2556感染滇黄芩再生苗的茎段和叶片,建立了毛状根培养及其植株再生体系。毛状根可直接从受伤的茎、叶外植体表面产生,在无外源激素的MS固体和液体培养基上自主生长,表现出典型的发根特征。毛状根茎段的诱导率较叶片高,最高可达到14.44%;经rolB基因PCR分析和甘露碱纸电泳检测,证明Ri质粒T-DNA已整合到滇黄芩基因组中并表达;毛状根在附加6-BA2mg/L和NAA0.2mg/L的MS固体培养基上直接诱导不定芽,并在MS培养基上生根,形成再生植株。获得的毛状根系经MS液体培养基培养30d后通过HPLC都能检测到黄芩苷,其中1个转化系黄芩苷含量为2.59%,是药材黄芩的0.20倍,而从3年单位时间黄芩苷生成量计算,毛状根是药材黄芩的7.18倍。本研究建立的毛状根培养体系,将对滇黄芩转基因技术的完善和利用毛状根生产黄芩苷的生物转化提供了实验基础。 相似文献
87.
Negligible contribution from roots to soil-borne phospholipid fatty acid fungal biomarkers 18:2ω6,9 and 18:1ω9 总被引:1,自引:0,他引:1
The phospholipid fatty acid biomarkers 18:1ω9, 18:2ω6,9 and 18:3ω3,6,9 are commonly used as fungal biomarkers in soils. They have, however, also been found to occur in plant tissues, such as roots. Thus, the use of these PLFAs as fungal biomarkers in sieved soil, which may still contain small remains of roots, has been questioned. We used data from a recent beech tree girdling experiment to calculate the contribution of roots to these biomarkers and were able to demonstrate that not more than 0.61% of 18:1ω9 and 18:2ω6,9 in sieved soil samples originated from roots (but 4% of 18:3ω3,6,9). Additionally, the abundance of the biomarker 18:2ω6,9 in the soil was found to be highly correlated to ectomycorrhizal root colonization, which further corroborates its fungal origin. PLFA biomarkers were substantially reduced in vital roots from girdled trees compared to roots of control trees (by up to 76%), indicating that the major part of PLFAs measured in roots may actually originate from ectomycorrhizal fungi growing inside the roots. We calculated, that even a near to 50% reduction in fine root biomass - as observed in the girdling treatment - accounted for only 0.8% of the measured decrease of 18:2ω6,9. Our results demonstrate that both 18:1ω9 and 18:2ω6,9 are suitable biomarkers for detecting fungal dynamics in soils and that especially 18:2ω6,9 is a reliable biomarker to study mycorrhizal dynamics in beech forests. 相似文献
88.
Initial decomposition rates, changes in organic chemical components (acid-insoluble fraction, holocellulose, polyphenols, soluble carbohydrates) and nutrient dynamics (K, Mg, Ca, P, N) were examined for fine roots and leaves of Japanese cypress (Chamaecyparis obtusa). Litterbag experiments designed to evaluate the relative effects of litter type and position of litter supply in the soil were carried out, considering that root and leaf litter typically occupy different locations and have different substrate qualities. Litterbags of roots and leaves were placed at two positions (on the soil surface and in the humus layer), and collected every 3 months over one year. The mass loss rate and N release were slower during root decomposition in the humus layer than during leaf decomposition on the soil surface. These differences between root and leaf decomposition were mainly caused by the litter type, and the effect of the position on decomposition was relatively small. Root litter was less influenced by position related effects, such as differences in humidity, than leaf litter, and this recalcitrant trait to environmental effects may be responsible for the slower mass loss rate and N release in root decomposition. The results of the present study suggest that fine roots are persistent in the soil and serve an important role in N retention in forest ecosystems because of their litter substrate quality. 相似文献
89.
《Land Degradation \u0026amp; Development》2017,28(2):648-663
Preferential flow is expected to provide preferential channels for plant root growth and variations in soil water flow, but few studies were conducted to imply the impacts of these changes, particularly for preferential flow in stony soils. This study aimed to characterize soil water flow and plant root distribution in response to preferential flow paths and quantitatively describe the relation between plant root distribution and soil water flow. Field dye‐tracing experiments centered on experimental plants were conducted to determine the root length density and soil water flow process. Laboratory analyses were performed to characterize changes in the relative concentration of the accumulated effluent and the degree of interaction between plant roots and soil water flow. The amount of fine plant roots with preferential flow paths decreased with increasing soil depth for all experimental plots. The largest plant roots were recorded in the upper soil layers to a depth of 20 cm. The relative concentration of the accumulated effluent increased with time and decreased with soil depth under saturated soil conditions, whereas a distinct early turning point for the relative concentration of the accumulated effluent was observed in the 0–20‐cm soil columns, and the relative concentration of the accumulated effluent initially decreased and then increased with time under unsaturated soil conditions. This study provides quantitative information with which to characterize the interaction between plant roots and soil water flow in response to preferential flow paths in soil–plant–water systems. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
90.
在旱地覆膜栽培条件下,临丰116具有良好的苗型结构和产量结构,抗旱节水优势强,叶片功能期长,耐高温,抗干热风,根穗比值大,抗倒伏,不早衰,穗大,粒重,产量高。该品种是旱地覆膜栽培较理想的配套品种。同时探讨了覆膜栽培配套品种的育种目标。 相似文献