Induced resistance has been evidenced as one of mechanisms of Trichoderma to control plantdiseases, however, no study showed the change of host proteomics in Trichoderma-induced resistance ofmaize against damping-off caused by Pythium ultimum Trow. The mechanism of Trichoderma harzianumRifai for controlling maize seedling disease caused by Pythium ultimum Trow was investigated firstly byproteome technique and the result suggested that T. harzianum strain T22 was not only able to promoteseedling growth but also protein accumulation. One-dimensional electrophoresis assay showed that morebands appeared on the gel with T22 or T22 combined with P. ultimum (T22 + P. ultimum) treatment than withother treatments. Enzyme assay showed that two chitinases of the root sample were more activated in thetreatments with T22 than in the other treatments without T22. Proteins in the seedling roots from the varioustreatments were separated through protein extraction and 2-D electrophoresis technique. In the seedlingsproduced from the T22-treated seeds, there were 104 up-regulated proteins and 164 down-regulated pro-teins relative to the control, and 97 and 150, respectively, after treatment with T22 + P. ultimum; however,with P. ultimum alone the values were much lower than with the other two treatments. The correlationcoefficient values were 0.72, 0.51 and 0.49 for the comparison of protein spot distribution on gel amongcontrol with T22, P. ultimum and T22 + P. ultimum, respectively. So it seemed that P. ultimum infection wasmore effective than T22 in interfering with the host proteome profile. Furthermore, analysis with MALDI-TOF-MAS showed that some important proteins associated with defensive reactions were identified in T22or T22 + P. ultimum treatments, including endochitinase, pathogenesis-related protein PRMS (pathogenesis-related maize seed), GTP-binding protein, isoflavone reductase and other proteins related to respiration. Allthose proteins are probably part of the network of resistance or development-related proteins.
The age of the alkali basalt from Daxizhuang in Jiaozhou, eastern Shandong, was determined to be 73.5±0.3 Ma by 40Ar-39Ar technique. The basalt gave high eNd(t) values of +7.5 and +7.6, suggesting that the primitive magma was derived from depleted asthenospheric mantle with a formation depth of about 65—95 km. Spinel-lherzolite xenoliths have been discovered in the basalt. The Fo values of olivine from the xenoliths range from 88 to 89. The estimated equilibrium P-T conditions of spinel-lherzolite xenoliths are about 2.0 GPa and 1010—1140℃, suggesting an equilibrium depth of about 65 km. Geochemical characteristics of the Late Mesozoic (125—115 Ma) mantle-derived rocks in Shandong Province suggest an enriched lithospheric mantle along the southern margin of the North China block. However, geochemical characteristics of the Late Cretaceous basalts in Daxizhuang and the equilibrium P-T condition estimated from the xenoliths suggest that the lithosphere at 73 Ma ago was as thick as that of the Cenozoic in the region. Additionally, the xenoliths are rich in basaltic-component, suggesting a derivation from a newly-formed lithosphere. Therefor, lithospheric thinning took place at a time interval between about 120 and 73 Ma along the southern margin of the North China block.
YAN Jun, CHEN Jiangfeng, XIE Zhi & ZHOU Taixi School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026, China
AMS14C dating and grain-size analysis for Core DD2, located at the north of the Yangtze River-derived mud off the Zhejiang-Fujian coasts in the inner shelf of the East China Sea, provide us a high-resolution grain-size distribution curve varying with depth and time. Data in the upper mud layer of Core DD2 indicate that there are at least 9 abrupt grain-size increasing in recent 2000 years, with each corresponding very well with the low-temperature events in Chinese history, which might result from the periodical strengthening of the East Asian Winter Monsoon (EAWM), including the first-revealed maximum temperature lowering event at around 990 a BP. At the same time, the finer grain size section in Core DD2 agrees well with the Sui-Tang Warming Period (600-1000 a AD) defined previously by Zhu Kezhen, during which the climate had a warm, cold and warm fluctuation, with a dominated cooling period of 750-850 a AD. The Little Ice Age (LIA) can also be identified in the core. It starts around 1450 a AD and was followed by a subsequent cooling events at 1510, 1670 and 1840 a AD. Timing of these cold events revealed here still needs to be further verified owing to some current uncertainty of dating we used in this study.
A novel process for electrodeposition of hydroxyapatite coating on titanium substrate was developed. The mechanism of the electrochemical reaction on the cathode was changed by adding H2O2 into the electrolyte. The evolution of H2 gas was erased. And owing to the fact that H2O2 posesses high tendency of being reduced, a fairly high cathodic current can be gained at a more positive potential than -1.0V. During the electrodeposition, 6%H2O2 is added, the temperature of deposition is fixed at 55℃ and pH of electrolyte is adjusted to 5.5. Dense and homogeneous film is crystallized at high rate. The mechanism of crystallize process was discussed.
