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991.
Anatomic Study of Female Sterility of Pinus tabulaeformis Carr. 总被引:3,自引:0,他引:3
ChengPengjun LiFenglan ZhengCaixia 《中国林学(英文版)》2003,5(1):13-19
The anatomic research on the mutant clone of Pinus tabulaeformis Carr.in the seed orchard in Xingcheng,Liaoning Provinces was carried out.The female cone of the mutant clone looked like normal,but its ovules degenerated in early stage.This paper trics to find out the reason and time of ovule abortion.It seems that the ovule abortion is probably caused by female sterility because the microspores of this mutant clone were normal.Through the serial observations on the one-year-old macrosporangiates and the ovules of two-year-old female cones of mutant and normal clone,it is found that the reason of ovule abortion in mutant clone is the failure of the mitosis of free nuclei in the female gametophyte,and the time is about in the early April. 相似文献
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994.
Jian Zhang Zhanqing Hao I. -Fang Sun Bo Song Ji Ye Buhang Li Xugao Wang 《Annals of Forest Science》2009,66(2):204-204
995.
The pattern of species co-occurrence is instrumental for understanding community assembly rules. In this paper, we analyzed the co-occurrence of tree species in a 25-ha old-growth temperate forest plot in Northeastern China. The analysis was conducted at seven scales from 5 m × 5 m up to 100 m × 100 m in order to determine the patterns of co-occurrence at different spatial scales. Our analyses were conducted for all species, species with larger abundances, species with larger sizes, and five phylogenetic-based species groups. Our results showed that at smaller scales, the co-occurrence patterns of all species, species with larger abundances, and species with larger sizes were significantly higher than expected by chance, suggesting that strong interspecies competition exists in the community. At larger scales, there was no significant difference compared to randomized matrices. The result indicated that plant assembly rules are only found at small spatial scales. However, when co-occurrence metrics were restricted to phylogenetic groups, we could not find any clear evidence of interspecific competition within these groups. In conclusion, we found that competition is an important assembly rule at small scales in governing tree communities of our temperate forest, although it is not the only process involved. The importance of other processes should also be taken into account to explain species co-occurrence patterns. 相似文献
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997.
[目的]研究不同道路防护林的滞尘能力及滞尘的动态变化和空间分布规律。[方法]在春季对3种道路防护林(油松林、圆柏林、银杏林)距道路不同宽度的滞尘量进行连续观测,对比3种道路防护林滞尘能力,分析降雨、极大风速、相对湿度、PM10等因子对滞尘动态的影响以及3种道路防护林滞尘的空间分布特征。使用单位叶干质量滞尘量(mg·g-1)表征叶面滞尘能力。[结果]表明:(1)3种植物叶面滞尘能力差异显著,圆柏银杏油松,分别为4.79±0.20、2.48±0.07、1.42±0.04 mg·g-1,单株和单位林分面积滞尘量均为圆柏林油松林银杏林;(2)3种道路防护林在外界影响下滞尘量处于动态变化之中,油松林具有比银杏和圆柏林更高的滞尘稳定性;(3)降雨量较低时3种道路防护林滞尘量均增加,降雨量较高时3种道路防护林滞尘量均降低,油松和银杏林的滞尘量更容易受降雨影响而降低;随着风速增大,3种道路防护林滞尘作用不断加强,风速继续增大时,油松和圆柏林滞尘量均有减少,银杏林滞尘量仍有显著增加。(4)3种道路防护林滞尘量在五环路侧(北)均高于香山路侧(南),油松和圆柏林均呈现为道路防护林中间位置为最低点,银杏林中间位置滞尘量最高。(5)油松和圆柏林滞尘量外部比内部变化大,银杏林滞尘量内部比外部变化大。[结论]道路防护林的滞尘效益受树种、林分结构、所处环境、天气条件等多方面因素共同影响,在营建和管理过程中应充分考虑各种因素,充分发挥滞尘作用。 相似文献
998.
The extraction of Artemisia hedinii Ostenf. et Pauls(A. hedinii) were rough and further isolated by chromatographic separation technology, and the antifungal activity of the component was evaluated by the the spore germination method. Furthermore, the composition of antimicrobial components was analyzed by high performance liquid chromatography-mass spectrometry (HPLC-MS). The results showed that 13 kinds of components(Fr.1-Fr.13) were rough isolated from the extraction of A. hedinii, in which the component Fr.5 showed the best antifungal activity. Four kinds of components (Fr.5.1-Fr.5.4) were obtained by the further separation of the component Fr.5. The EC50 of A. hedinii crude extraction on Alternaria alternate (A.alternate) spores was 5.04 g/L, and that of the component Fr.5.2 was 0.57 g/L. The HPLC-MS results showed that the components of Fr.5.2 mainly contained deoxy double hydroxyl artemether (17 %),deoxy dihydroartemisinin (43.65 %) and deoxyartemisinin (16.15 %). The content of dihydroartemisinin of component Fr.5.2 was calculated as 40.95 % by using dihydroartemisinin as the standard. The EC50 of dihydroartemisinin on A.alternate was 2.70 g/L, indicating that the major antifungal matter in component Fr.5.2 was artemisinin derivatives. © 2018, Editorial Board of «Chemistry and Industry of Forest Products». All right reserved. 相似文献
999.
采取浸提法从丑橘、甜橙、甜心柚、血橙、芦柑5种柑橘属果皮中提取多糖并测定其含量。结果表明,血橙果皮中含糖量在5种果皮中最低,其次为甜橙果皮、甜心柚果皮、芦柑果皮,丑橘果皮中含糖量在5种果皮中最高。甜橙果皮和甜心柚果皮含糖量差距不大。 相似文献
1000.