The ability of burdock fructooligosaccharide (BFO), a type of linear fructooligosaccharide extracted and isolated from the roots of Arctium lappa, to induce systemic acquired resistance (SAR) was studied in cucumber seedlings. BFO strongly induced changes in salicylic acid (SA) and SA-glucoside (SAG) in BFO-treated leaves, and similar changes of SA and SAG were also found in untreated leaves of the same seedling. The level of SA in the first leaves sprayed with BFO (5.0 g ⁄ l) increased by 3.6 times after 24 h and then gradually declined from 48 to 96 h and finally decreased to a nadir at 120 h. The SAG level increased by 2.1 times at 24 h and then continued to increase to about 10.0 times as much as that in control from 96 to 120 h. The levels of SA in the untreated leaves of the same seedling only increased by 1.6-1.9 times during the period of 24-72 h followed by a decrease at 120 h, while SAG increased by 1.1 times at 24 h but steadily continued to increase to its maximum from 24 to 120 h. In summary, the patterns of expression of SA and SAG in the untreated leaf were similar to that of the treated leaf of the same seedling, while the pattern of expression of SAG was quite different from that of SA both in the treated and untreated leaves. Pretreatment with BFO reduced the lesions caused by Colletotrichum orbiculare by 56.8%. Additionally, the amount of lignin and the activities of some defensive enzymes including peroxidase, superoxide dismutase, polyphenoloxidase and b-1,3-glucanase significantly increased in the first leaves pretreated with BFO and followed with C. orbiculare inoculation. These results demonstrate that BFO can enhance the contents of endogenous SA, the resistance against C. orbiculare, and the activities of defensive enzymes of cucumber seedlings.

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Firstly, the parameters of cohesive zone model in ABAQUS software are calibrated through the cohesive constitutive model determined by cohesive potential energy, which is provided by Oriz and Pandofi（1999）. Then, the validity and liability are verified by the single element example which compares extended finite element simulation with experimental results. Lastly, it puts forward the model of FEM based on the highway pre-sawed cracks. The curve of CMOD with changing temperature is obtained, and the curve can be divided into three stage segments. The middle stage segment changes dramatically for the local cracking in the crack tip field between asphalt surface and base. The research results illustrate the cracking mechanisms of asphalt pavement under changing temperature.

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Asphalt pavement with semi-rigid base is the major structure adopted in the new built highway and municipal roads in China. So as to reduce the unfavorable impact on the rehabilitation of municipal roads which require quick resumption of traffic, better base materials should be adopted. If a pavement base fails, the flexible base, i.e. large stone asphalt mixture (LSAM), should be employed in the pavement rehabilitation practice. Focusing on the practice pavement sections using LSAM as base in Hangzhou municipal roads, the effect factors of subgrade modulus, base modulus and base thickness on surface deflection and bending strain in base bottom is analyzed. That work is done through finite element method of software BISAR3.0. The results provide a practice reference for municipal roads rehabilitation needing to open traffic early.