黑麂(Muntiacus crinifrons)和贡山麂(M. gongshanensis)的比较细胞遗传学研究

本工作采用多种染色体显带技术较为详细地研究了黑麂和贡山麂的细胞遗传学特性。结果表明：（1）黑麂和贡山麂的染色体数目相同，均为2n = 8♀、9♂。染色体形态相似，两者雄性的常规核型很相似，几乎无法区分。（2）黑麂与贡山麂的X染色体均易位至常染色体，形成复合X染色体。但它们易位的常染色体不同。由于X染色体易位至不同的常染色体，可能造成杂种减数分裂配对异常，这对生死隔离和物种形成有着特殊重要的意义。（3）黑麂和贡山麂染色体的G带具有较高同源性。染色体长臂G带几乎完全相同。复合X染色体的短臂即X染色体均为三条暗带。差异主要在染色体短臂。G带的差异可能涉及一次相互易位、一次倒位、异染色质的变化以及染色体片段的丢失。（4）黑麂和贡山麂均有两对NORs，都分别位于No.1染色体臂和No.3染色体为同源染色体。因而，进一步证明了黑麂和贡山麂染色体具较高的同源性。（5）黑麂和贡山麂的C带显示的结构异染色质位于着丝粒区域，为着丝粒异染色质。贡山麂的着丝粒异染色质含量明显少于黑麂。C带分布与CMA_3荧光带在着丝粒区域的分由基本一致，说明着丝粒异染色质富含GC序列。在某些着丝粒区域也有DA/DAPI带分布，说明着丝粒异染色质也可能包含－部分富含AT序列。（6）黑麂和贡山麂的限制性内切酶AIuI、HaeIII的C样带表明，X染色体有相同的酶带分布，其余染色体的差异与C带的一致。在酶带区域内，无AIuI、HaeIII两种酶的识别序列，指示富含AT序列。此推论得到DA/DAPI荧光带的证实。各种带型分析比较表明，黑麂和贡山麂染色体具较高的同源性。它们可能有一个共同的祖先。

Spatial and seasonal distributions of carbonaceous aerosols over China

IEECAS SKLLQG

Evolution of the Ordos Plateau and environmental effects

IEECAS SKLLQG

Isolation and characterization of photosystem II from the filamentous sporophyte of Porphyra yezoensis

Thylakoid membranes were isolated and purified from diploid filamentous sporophytes of Porphyra yezoensis Ueda using sucrose density gradient ultracentrifugation (SDGUC). After thylakoid membranes were solubilized with SDS, the photosystem II (PSII) particles with high 2, 6-dichloroindophenol (DCIP) photoreduction activity were isolated by SDGUC. The absorption and fluorescence spectra, DCIP photoreduction activity and oxygen evolution activity of the thylakoid membranes and PSII particles were determined. The polypeptide composition of purified PSII particles was distinguished by SDS-PAGE. Results showed that PSII particles of sporophytes differed from the gametophytes in spectral properties and polypeptide composition. Apart from 55 kDa D1-D2 heterodimer, CP47, CP43, 33 kDa protein was also detected. However, cyt c-550, 20 kDa, 14 kDa and 16 kDa proteins found in PSII particles from gametophytes were not detected in the sporophytes.

Comparison between compsopogon coeruleus and porphyra yezoensis in their O-2 evolution rates and phycobilisome composition

In order to investigate the possible effects of the ecological environment on photosynthetic activity and the major light harvesting complex, the oxygen evolution rates and composition of phycobilisome from marine red alga Porphyra yezoensis Ueda and freshwater red alga Compsopogon coeruleus (Balbis) Montagne, which could grow and reproduce under salinity up to 35 ppt, were studied. The results showed that the oxygen evolution rate of P. yezoensis in seawater was significantly higher than that of C. coeruleus in freshwater, and P. yezoensis tolerated inorganic ions at a relatively higher concentration than C. coeruleus. Moreover, the phycoerythrin (PE) of P yezoensis was R-phycoerythrin containing alpha, beta, and gamma subunits comprised phycoerythrobilin and phycourobilin. In contrast, the PE from C. coeruleus consisted of alpha, beta, and gamma subunits comprised only phycoerythrobilin but not phycourobilin, suggesting that the PE from C. coeruleus was of a new type.

Seasonal and interannual variation in water vapor and energy exchange over a typical steppe in Inner Mongolia, China

In this study, we conducted eddy covariance (EC) measurements of water vapor exchange over a typical steppe in a semi-arid area of the Inner Mongolia Plateau, China. Measurement sites were located within a 25-year-old enclosure with a relatively low leaf area index (similar to 1. 5 m(2) m(-2)) and dominated by Leymus chinensis. Energy balance closure was (H + LE) = 17.09 + 0.69 x (Rn - G) (W/m(2); r(2) = 0.95, n = 6596). Precipitation during the two growing seasons of the study period was similar to the long-term average. The peak evapotranspiration in 2004 was 4 mm d(-1), and 3.5 mm d(-1) in 2003. The maximum latent heat flux was higher than the sensible heat flux, and the sensible heat flux dominated the energy budget at midday during the entire growing season in 2003; latent heat flux was the main consumption component for net radiation during the 2004 growing season. During periods of frozen soil in 2003 and 2004, the sensible heat flux was the primary consumption component for net radiation. The soil heat flux component was similar in 2003 and 2004. The decoupling coefficient (between 0.5 and 0.1) indicates that evapotranspiration was strongly controlled by saturation water vapor pressure deficit (VPD) in this grassland. The results of this research suggest that energy exchange and evapotranspiration were controlled by the phenology of the vegetation and soil water content. In addition, the amount and frequency of rainfall significantly affect energy exchange and evapotranspiration upon the Inner Mongolia plateau. (c) 2007 Published by Elsevier B.V.