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101.
为了揭示青藏高原高寒草原优势物种青藏苔草(Carex moorcroftii)和紫花针茅(Stipa purpurea)对高原特殊环境的适应性,该文研究了 它们的叶片结构在自然环境梯度下的变化以及这些变化与生态因子之间的关系。结果表明:这两个物种叶片的大多数结构特征在各个样地间变 化显著,其结构特征与环境因子间存在显著的相关关系。紫花针茅叶肉细胞大小随土壤有效K含量的增高而减小,下表皮细胞厚度和韧皮部面积 随生长季云盖度的增高而增加,单一导管半径和导管平均面积随生长季月均湿度的增加而增大;青藏苔草上表皮细胞厚度随生长季月均最低温 的降低而增厚,泡状细胞厚度(径向直径)随大陆度的增强而增加,上表皮细胞大小随土壤pH值的增大而增大,导管总数和韧皮部面积随土壤 速效P含量的增高而增加。青藏苔草的保护组织、光合组织以及综合指标变异系数明显大于紫花针茅,仅维管组织指标变异系数小于紫花针茅。 相似文献
102.
采用PCR-SSCP方法检测猪胰岛素样生长因子2 (insulin-like growth factor 2,IGF2)基因外显子3多态性,分析其对初生重、断奶重、6月龄重和背膘厚的遗传效应.根据猪IGF2基因的DNA序列(AY044828)设计引物,结果在其扩增片段上检测到多态性,对纯合子进行测序,发现IGF2-ex3-A36T和IGF2-ex3-G109A两个多态性位点,并且这2个多态性位点完全连锁,检测到3种基因型(A36A/G109G,A36T/G109A 和 T36T/A109A).统计结果表明,基因型在各品种中分布不一致,长白猪和大白猪与莱芜猪、大薄莲猪、沂蒙黑猪和里岔黑猪比较基因型分布差异极显著(P<0.01);其它猪种间基因型分布差异均不显著(P>0.05).固定效应模型分析结果表明,初生重和背膘厚基因型间差异显著(P<0.05),而断奶重和6月龄重基因型间差异不显著(P>0.05).最小二乘分析结果表明,A36A/G109G基因型个体同A36T/G109A和 T36T/A109A基因型个体比较初生重和背膘厚的差异显著(P<0.05),3种基因型初生重的大小排列顺序为A36A/G109G < A36T/G109A < T36T/A109A,背膘厚的大小排列顺序为A36A/G109G > A36T/G109A >T36T/A109A.因此,推测IGF2基因对个体的初生重和胴体瘦肉率存在一定的影响,将IGF2基因应用于猪育种过程中的标记辅助选择,将可以改善猪肉品质,加快猪的育种进程. 相似文献
103.
104.
《中国科学:生命科学英文版》2008,(12)
The responses of the early development of Laminaria japonica collected from Kiaochow Bay in China to enhanced ultraviolet-B radiation (UV-B, 280—320 nm) were studied in the laboratory. The low UV-B ra-diations (11.7—23.4 J·m-2·d-1) had no significant effects on zoospores attachment, but when the UV-B dose > 35.1 J·m-2·d-1 the attachment decreased significantly compared with the control. Germination of embryospores was >93% under the low (11.7—35.1 J·m-2·d-1) doses, and in the range of 78.5%—88.5% under the high (46.8—70.2 J·m-2·d-1) UV-B doses, indicating a significant radiation effect. Under the higher UV-B exposure (35.1—70.2 J·m-2·d-1), all of the few gametophytes formed from embryospores died 120 h post-release. After exposure to the low UV-B radiation (11.7—23.4 J·m-2·d-1), the formation of sporophytes decreased and the female gametophyte clones increased compared with the control. However, the sex ratio and the relative growth of female gametophytes/sporophytes had not signifi-cantly changed. According to the results, enhanced UV-B radiation has a significant effect on the early development of L. japonica under laboratory conditions, suggesting that the UV-B radiation could not be overlooked as one of the important environmental factors influencing the ontogeny of macroalgae living in marine ecosystems. 相似文献
105.
Bioassay-guided investigation was performed to identify the active constituents from a methanol extract of Polygala japonica, a folk medicinal plant widely used in China to treat inflammatory diseases. The n-BuOH and EtOAc fractions of the P. japonica methanol extract, which show significant anti-inflammatory activity in in vivo test, were further subjected to column chromatography to afford six triterpene glycosides, marked here as saponins 1–6. All compounds were evaluated for their anti-inflammatory activity in the carageenan-induced mouse paw edema test, and saponins 1, 4 and 5 showed significantly anti-inflammatory effects on both phases of carageenan-induced acute paw edema in mice. Saponin 5 was also found to significantly inhibit the production of inflammatory mediators – nitric oxide (NO) in LPS-stimulated RAW264.7 macrophages, with no obvious effects on macrophage viability. 相似文献
106.
Li-MingFAN Hong-PingHE Yue-MaoSHEN Xiao-JiangHAO 《植物学报(英文版)》2005,47(1):120-123
Two new hetisine-type C20-diterpenoid alkaloids named spiraqine (1) and 6-hydroxylspiraqine (2), and four known alkaloids, namely spiredine (3), spiradine A (4), spiradine B (5), and spirasine V/VI (6),were isolated from Spiraea japonica L. f. var.fortunei (Planchon) Rehd. The structures of the alkaloids were elucidated using nuclear magnetic resonance analysis (1H-NMR, ^13C-NMR, DEPT, HMQC, and HMBC) and mass spectrometry data. 相似文献
107.
108.
Synthesis of (R)-2-trimethylsilyl-2-hydroxyl-propionitrile via asymmetric transcyanation of acetyltrimethylsilane with acetone cyanohydrin in an aqueous/organic biphasic system catalyzed by (R)-hydroxynitrile lyase from Prunus japonica seed meal was successfully carried out for the first time. The optimal volume ratio of aqueous to organic phase, buffer pH value and reaction temperature were 15% (v/v), 5.0 and 30°C, respectively, under which both substrate conversion and product enantiomeric excess (ee) were 99%. Silicon atom in the substrate showed great effect on the reaction. Acetyltrimethylsilane was a much better substrate for (R)-hydroxynitrile lyase from Prunus japonica than its carbon analogue. 相似文献
109.
The Japenese eel, Anguilla japonica, is generally assumed to be composed of a single population with wide distribution range, and some genetic studies using allozyme or mitochondrial DNA methods supported this population model. However, one genetic study suggested the existence of multiple populations in this species, and thus, more detailed studies on the population structure is needed. Here we characterized a total of 11 microsatellite markers of the Japanese eel. These will serve as powerful tools for detailed population study for the Japanese eel, though two of them showed the significant departure from the Hardy–Weinberg expectations. 相似文献
110.
V. Debacker A. Rutten T. Jauniaux C. Daemers J-M. Bouquegneau 《Biological trace element research》2001,82(1-3):87-107
Combined effects of heavy-metal contamination (Cu, Zn, and CH3Hg) and starvation were tested on common quails (Coturnix coturnix japonica) and used as a model for comparison with a wild common guillemot (Uria aalge) population found stranded at the Belgian coast. Appropriate heavy-metal levels were given to the quails to obtain concentrations
similar to those found in the seabirds’s tissues. The contaminated animals were then starved for 4 d to simulate the evident
malnutrition symptoms observed at the guillemot’s level. In such conditions, food intake and total-body weight are shown to
decrease in contaminated individuals with simultaneous significant hepatic and renal increase of the heavy-metal concentrations.
Like guillemots, higher heavy-metal levels were observed in those contaminated quails that had also developed a cachectic
status characterized by a general atrophy of their pectoral muscle and complete absence of subcutaneous and/or abdominal fat
depots. Although likely the result of a general protein catabolism during starvation, it is suggested that these higher metal
levels could as well enhance a general muscle wasting process (cachectic status). 相似文献