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1.
Specimens from Scotland, S. and C. Norway were grown in the botanical garden of Bergen, Norway. Some of the Scottish specimens came from a meristem tissue culture. The specimens were compared by a principal component analysis of lipids and related compounds, and of morphological characters from leaves and flowers. The populations differed from each other, but some overlap was found in leaf characters. The results are discussed in relation to distribution and immigration history, and it is argued that the differences among the populations may have evolved in postglacial time. 相似文献
2.
人工樟子松—差不嗄蒿植被及其固沙作用 总被引:6,自引:2,他引:4
植物固沙是整治沙漠和沙漠化土地的一种有效措施。人工植被的建立是植物固沙的必然结果。人工植被的演替、稳定性及其对环境的影响直接关系到流沙的固定程度。因此,本文旨在探讨人工樟子松(Pinus sylvestris var. 相似文献
3.
<正> 多年生草本,茎直立,褐黄色或淡紫褐色,仅上部具着生头状花序的分枝,此枝长3—10厘米。茎、枝、叶面微被淡黄色短柔毛或近无毛;叶面具稀疏白色腺点及小凹点,背面具稀疏的蛛丝状薄绒毛;茎下部叶末见;中部为上部叶具短柄或近无柄,叶片卵形或近圆形,长、宽3.5—4.6厘米,(三一)二回羽状全裂,每侧裂片4—6枚,每裂片常再分裂,每侧具 相似文献
4.
Mountain big sagebrush steppes in Wyoming have strong spatial patterning associated with topography. We describe the spatial variability of vegetation in a sagebrush steppe, and test the relationship between topography and vegetation using canonical correlation. Results of the analysis suggest that the main control over vegetation distribution in this system is wind exposure. Exposed sites are characterized by cushion plant communities and Artemisia nova, and less exposed sites by the taller sagebrush species Artemisia tridentata ssp. vaseyana. Topographic depressions and leeward slopes are characterized by aspen stands and nivation hollows. Measurements of soil microclimate suggest that a major influence of topographic position on vegetation is snow redistribution and its effect on soil moisture and temperature.Abbreviations ARNO
Artemisia nova
- ARTRW
Artemisia tridentata ssp. wyomingensis
- ARTRV
Artemisia tridentata ssp. vaseyana
- PUTR
Purshia tridentata
- RIP
riparian community
- POTR
Populus tremuloides
- NIV
nivation hollow community 相似文献
5.
Callus formation from protoplasts of Artemisia sphaerocephala Krasch and some factors influencing protoplast division 总被引:2,自引:0,他引:2
Round wormwood (Artemisia sphaerocephala Krasch) seeds were germinated on Murashige & Skoog (1962) medium without plant growth regulators. The hypocotyls of seedlings were sliced and cultured on M1 medium with 2,4-dichlorophenoxyacetic acid (9.05 M) to induce callus. The induced calluses were subcultured on the same medium. Ten day old calluses were used to isolate protoplasts in an enzyme solution with 0.65 M mannitol. Protoplast yield strongly depended upon the state of callus cultures. Certain amount of hemicellulase could improve protoplast isolation. Purified protoplasts were cultured in modified Kao & Michayluk (1975) medium with 0.60 M mannitol as osmoticum, suggesting that protoplasts of A. sphaerocephala need a high initial osmolarity. Protoplasts generally divided evenly and the percentage of first division could reach 10%. Kinetin exhibited a positive effect on initial cell division. Furthermore, we studied the effect of protoplast density and vitamin C on sustained growth of protoplasts. After forty days, 1 mm calluses in diameter formed.Abbreviations CH
casein hydrolysate
- 2,4-D
2,4-dichlorophenoxyacetic acid
- KM8P
Kao & Michayluk (1975) protoplast medium
- MS
Murashige & Skoog (1962) medium
- MES-2
(N-morpholino)ethanesulfonic acid 相似文献
6.
Paula Tatiana Lopes Seixas Antonio Jacinto Demuner Luiz Claudio Almeida Barbosa Cristiane Isaac Cerceau Daiane Einhardt Blank Marcelo Henrique Dos Santos Elizeu de Sá Farias Marcelo Coutinho Picanço 《Journal of Applied Entomology》2023,147(2):116-125
Aedes aegypti L. (Diptera: Culicidae) is a vector for serious diseases in tropical regions. This pest is mainly controlled by commercial larvicides but the application of such products has led to environmental problems. Essential oils (EO) have been consistently reported as molecules with insecticidal activity and can be used to produce more environmentally friendly larvicides in the control of A. aegypti. In this study, the larvicidal effect of essential oils (EO) from the leaves of three Artemisia species was evaluated against A. aegypti. The oils were obtained from steam distillation and their chemical composition was determined by gas chromatography–mass spectrometry. The EO of Artemisia camphorata was the most active in the screening bioassay and presented LC50 and LC95 of 64.95 and 74.18 μg ml−1, respectively. In addition, we found that germacrene D-4-ol was the constituent responsible for the toxicity of this EO. Artemisia camphorata EO and its major constituent, germacrene D-4-ol, are promising for the development of natural larvicides against A. aegypti. 相似文献
7.
陕北黄土高原蒿属植物的分类与分析 总被引:1,自引:0,他引:1
陕北黄土高原有蒿属植物30种1变种,居该地产种子植物属中所含种数的首位。所产蒿属植物在不同的植被带中梯度变化明显,替代现象显著。在生态类型上,旱生类型从南向北递增,中生类型从南向北递减。在区系组成上可分为6种分布区类型,即:我国特有分布,3种;温带亚洲分布,14种1变种;北温带及中亚分布各4种;旧世界温带分布,3种;东亚分布的2种。可见陕北黄土高原蒿属植物种类丰富,梯度变化明显,旱化现象显著,地理成分复杂,但以温带亚洲分布类型为主,兼有其它成分,属典型的温带性质。 相似文献
8.
Abstract. Single species and bivariate distribution patterns in a semi-arid shrubland in southeastern Spain, dominated by the tall leguminous shrub Retama sphaerocarpa, were investigated by second-order spatial analysis based on Ripley's K-function. Shrubs were significantly clumped because of a strong association of dwarf shrubs, mostly Artemisia barrelieri, under the canopy of Retama. Retama shrubs were randomly distributed, but when different size-classes were analysed separately, the pattern changed from significantly clumped to random and then to regular with increasing canopy diameter, suggesting increasing intraspecific competition with shrub size. Artemisia was significantly clumped at all scales because of aggregation under the canopy of large Retama shrubs. The association between the species became stronger with increasing canopy diameter of Retama shrubs, suggesting that facilitation prevailed over interspecific competition because of niche separation in different tiers, both above and below ground. Retama shrub size thus determined both the type of pattern for its own size class and tier, and the scale and intensity of the association with its understorey shrubs. 相似文献
9.
10.
Rick G. Kelsey Jerry W. Thomas Thomas J. Watson Fred Shafizadeh 《Biochemical Systematics and Ecology》1975,3(4):209-213
The sesquiterpene lactones and chromosome numbers for three chemical races of Artemisia tridentata ssp. vaseyana have been examined from four populations in western Montana. TLC analysis of the sesquiterpene lactones in the seeds and seed producing parents demonstrated that genetic exchange does occur between sympatric sesquiterpene lactone chemical races. However, other evidence suggests that introgression between these races is restricted to zones of sympatry. There appears to be no correlation between chromosome numbers and sesquiterpene lactone races. 相似文献