共查询到20条相似文献，搜索用时 140 毫秒
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《中南林业科技大学学报(自然科学版)》2016,(8)
确定森林群落中林下草本植物的分布及其对光照的响应,不仅能揭示草本植物对光的生态需求,而且能为其引种和利用提供关键参考。在东源康禾自然保护区的常绿阔叶林内设置2 hm~2样地,样地划分为50个20m×20 m样方,在样方内设置小样方进行林下草本植物(包括禾本科竹亚科植物)调查。用半球面影像技术测定林下光照指标,进而分析草本植物分布与林下光环境的关系。结果表明,林下光环境的变异为草本植物的生长提供了多样的小生境,不同光照需求的物种在样地内均广泛分布;林下散射光与林下草本分布的除趋势对应分析(DCA)排序轴的相关性高于直射光与排序轴的相关性,说明林下散射光与林下植物的分布关系更为密切;不同光照总立地因子的样方组间草本植物的多度和丰富度没有显著差异,但非参数回归分析的结果清晰地反映了不同草本植物对光照响应的差别,如山麦冬Liriope spicata喜阴且不耐强光,黑莎草Gahnia tristis、箬竹Indocalamus tessellatus在不同光照条件下生长变化不大,说明物种对光照的变化不敏感、适应性更强。在草本植物的引种和利用过程中,可以结合目标地点的光照条件选择适生的物种。 相似文献
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文净香草是澳大利亚植物学家迪克小组,10多年来通过生物工程技术,改变天竺葵植物的染色体结构,从而获得具有新的遗传结构的芳香类天竺葵属多年生观叶植物。1形态特征文净香草植株高1m左右,叶片肥大深绿,1盆冠幅20～30cm,蚊净香草的驱蚊面积为10～20m2。2生长习性喜阴,生长期不能强光照,尤其在夏季应加强遮 相似文献
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北美枫香Liquidambar styraciflua为金缕梅科落叶乔木,原产北美,在美国东南部有大量分布。大型阔叶树种,树高可达30m,叶片5~7裂,互生,长10~18cm,叶柄长6.5~10cm;春夏叶色暗绿,秋季叶色变为黄色、紫色或红色;落叶晚,在部分地区叶片挂树直至次年2月。北美枫香喜光照、耐湿润,耐低温,可耐-23.℃低温。年生长量0.6~1m左右,寿命在100年左右。成龄树耐部分遮荫,根深抗风,适应性强。栽植在肥沃、潮湿、冲积性粘土和江河底部的肥沃粘性微酸土地生长最好,但种植在山地和丘陵地区也有良好表现。因其生长迅速,花型独特,秋叶色彩斑斓,于田间道旁与其他… 相似文献
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This study investigated the dynamic modulus of elasticity (DMOE) of wood panels of Fraxinus mandshurica, Pinus koraiensis, and Juglans mandshurica using the natural frequency measurement system of fast Fourier transform (FFT). The results were compared with the static
modulus of elasticity (E
S) tested by a mechanical test machine. The results show a significant correlation between E
S, transverse vibration DMOE (E
F), and longitudinal vibration DMOE (E
L). For all of these species, the correlation between E
S, E
F and E
L is more significant than the individual species, which indicated that the FFT method is universal. The correlations between
E
S and sample’s density (ρ) are significant, but the correlation coefficient of E
S and ρ is lower than those between E
F, E
L and E
S. The E
S of wood is more accurately tested by the analysis based on FFT measurement than by the estimation based on density.
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Translated from Scientia Silvae Sinicae, 2005, 41(6): 126–131 [译自: 林业科学, 2005, 41(6): 126–131] 相似文献
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Wu Xingyin Zhang JinghuaForest Pest Control Quarantine Station of Archeng City of Heilongjiang ProvinceXiang Cunti Li Guisheng '''' Shao Zhongwen Liu Xiaoguang Ma LiyaNortheast Forestry UniversityZhang Xianwen Li Zhuo Xie Guicai Dang WenqiangArcheng Forestry Bureau of Heilongjiang Province 《林业研究》1991,2(2):7-16
The poplar bacterial canker caused by Erwinia sp is a serious disease spreading inmost parts of Northeast China,where poplars are cultivalted.The disease seriously infects thosepoplars belonging to section Aigeiros or the intersection hybrids of section Tacamahaca and section Aigeiros and their clones.Five fine poplar cultivars resistant to the bacterial canker have been ob-tained by screening tests.They are Lz_2(Populus simonii×nigra var.italica),A_(15)(P.×sp.)613(P.×sp.),A_(102)and A_(98)(P.simonii×sp.)T following chemicals are obviously effective,such as:50％DT germicide ,40％ XF-136 and 10％ C.C.M.A.or 12.5％ ramphencol and 50,000 ppm/mlvalidamycin,with which the stems or roots can be watered. 相似文献
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Hitoshi Sakio 《Journal of Forest Research》2005,10(4):341-346
The effects of flooding on growth of seedlings were compared over a 7-month period (April–November) among six different woody species: Aesculus turbinata, Cercidiphyllum japonicum, Fraxinus platypoda, Pterocarya rhoifolia, Pterostyrax hispida, and Quercus mongolica var. grosseserrata. Flooding reduced the shoot length of F. platypoda, P. rhoifolia, C. japonicum, P. hispida, and Q. mongolica var. grosseserrata seedlings but did not affect that of A. turbinata seedlings. Among control seedlings, shoot elongation occurred once in A. turbinata and twice in F. platypoda and Q. mongolica var. grosseserrata; the other species continued to grow from April to August. Among the flooded plants of all species, shoot elongation occurred only once at the beginning of the growing season. On August 25, flooding significantly reduced the number of developed leaves as compared with control plants except for A. turbinata. In the flooded plants except for F. platypoda, leaf fall began on June 30; in controls, by contrast, the number of developed leaves increased until August 25. Flooding reduced the total dry weight increment in all species. The survival ratio of flooded plants after the experiment differed with species. All of the F. platypoda and A. turbinata seedlings survived the flooding treatment, while only 20% of P. hispida and 30% of Q. mongolica var. grosseserrata survived. Flooding seriously affected the growth of riparian pioneer species including P. rhoifolia, C. japonicum, P. hispida, and Q. mongolica var. grosseserrata. The effects of flooding on growth of the seedlings differed with the tree species because of differences in leaf-emergence pattern and physiological flood tolerance. The responses of tree seedlings to flooding reflected species habitats and growth patterns. 相似文献
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Four regions of chloroplast DNA were sequenced as a prospective genetic marker to identify Japanese representatives of Cyclobalanopsis: Quercus acuta, Q. sessilifolia, Q. salicina, Q. myrsinaefolia, Q. glauca, and Q. gilva. We found that Q. gilva was distinguished from other species based on both the trnL-trnF and trnT-trnL intergenic spacers. The evidence shows good coincidence with the fact that Q. gilva has several peculiar morphological features distinguishable from those of other species. There was no difference in trnL intron and matK. Both trnT-trnL and trnL-trnF intergenic spacers are capable of being used as genetic markers to identify Q. gilva among Cyclobalanopsis species.Part of this paper was presented at the 48th annual meeting of the Japan Wood Research Society, Shizuoka, April 3–5, 1998 相似文献
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落叶松水浸液对胡桃楸幼苗生长的影响 总被引：3，自引：0，他引：3
YANG Li-xue 《林业研究》2005,16(4):285-288
A study was conducted to detect the effect of water extracts from different parts such as root, bark, branch and leaf, of adult larch, Larix gmelini, trees on growth of Manchurian walnut, Juglans mandshudca, seedlings and the allelopathy between the two tree species. Four concentrations （100 g. kg i, 50 g. kg^-1, 25 g. kg^-1 and 12.5 g. kg^-1） were prepared for each kind of extracts. Result showed that the water extracts with low and moderate concentrations accelerated the growth of collar diameter and increased biomass and root/shoot ratio of walnut seedlings. The water extracts from branches and barks with low and moderate concentrations accelerated the height growth of the seedlings, while those from leaves and roots slightly decreased the height growth of seedlings. The fact that application of water extracts of larch improved the growth of Manchurian walnut attributes possibly to the allelopathy between the two tree species. 相似文献
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C. Saint-Pierre 《Agroforestry Systems》1991,13(2):159-176
A review of agroforestry practices in one lowland and one highland community of Xishuangbanna [Yunnan, P.R. China] has been carried out. Multilayer homegardens and taungya for fuelwood in the lowlands, tea shaded by natural forest and shellac production in a swidden farming system in the highlands are described. The extention of these agroforestry systems in Xishuangbanna is analyzed.Farming systems are facing problems related to shifting cultivation and to a rapid development of rubber which induce a negative evolution of these agroforestry systems.New agroforestry patterns based on Chinese research work, with rubber trees or with shade medicinal plants, are in extension in villages and in state farms.
Résumé Un inventaire des systèmes agroforestiers du Xishuangbanna [Yunnan, R.P. Chine] a été réalisé: jardins à plusieurs étages et production de bois feu par système de taungya dans un village de plaine, thé à l'ombre de forêt naturelle et production de gomme-lacque dans un système d'agriculture sur brûlis dans un village de montagne.Les systèmes de production sont confrontés aux problèmes liés à l'agriculture sur brûlis, et au développement de l'hévéa. Il en résulte des évolutions négatives de ces practiques agroforestières.De nouveaux modèles agroforestiers, à base d'hévéa ou de plantes médicinales d'ombre, se développent dans les villages et dans les fermes d'état á la suite des travaux de la recherche chinoise.相似文献
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Shuang-Huang-Lian (SHL), a traditional Chinese formula containing Lonicerae japonicae flos (LJF), Scutellariae radix (SR) and Forsythiae fructus (FF), is commonly used to treat acute upper respiratory tract infection, acute bronchitis and light pneumonia. Forsythoside A is one of the main active ingredients in Forsythiae fructus, a key herb in SHL. In the present study, effects of different compositions in SHL on the intestinal absorption of forsythoside A were investigated. The observations from in situ intestinal circulation model showed that A/%(h− 1) of forsythoside A in FF + LSF, FF + SR and SHL were all reduced greatly compared with that in FF. However, in pharmacokinetics study, Cmax and AUC0 → 1440 of forsythoside A all increased and T1/2 prolonged in SHL, FF + LJF and FF + SR compared with FF. The results indicated that the different compositions of SHL decreased absorption but increased bioavailability of forsythoside A, which may be related to its metabolism inhibited in intestine or liver. 相似文献
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[目的]模式植物在木本植物中鉴定的许多重要调控因子家族在木本植物中出现了基因家族成员扩张,但ARRs家族作为细胞分裂素响应调节因子在杨树基因组中成员数量反而减少,其在木本植物中如何行使功能需要进一步研究。[方法]本研究通过生物信息学构建PtRRI启动子与GUS融合表达载体,检测植物激素处理后PtRRI表达量和检测PPtRRI::GUS转基因植株在生根过程中GUS信号等方法,对杨树PtRRI基因的组织特异性表达模式进行分析。[结果]表明:PtRRI在杨树根部、形成层、木质部表达量相对较高,PtRRI转录受6-BA激素诱导,与其在不定根发育过程中激素调控下的表达相一致。[结论]PtRRI基因可能参与杨树的次级生长。 相似文献
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[目的]分离并量化土壤自养呼吸和异养呼吸,探讨各自贡献率及其随季节变化的动态特征。[方法]采用壕沟法和气体红外分析法,研究黄河小浪底库区山地栓皮栎人工林土壤总呼吸、自养呼吸和异养呼吸速率的季节动态变化、贡献率和环境影响因子。[结果]表明:栓皮栎人工林总土壤呼吸、自养呼吸和异养呼吸均呈夏季速率高、冬季速率低。栓皮栎土壤总呼吸、自养呼吸及异养呼吸速率与5 cm土壤温度均呈极显著指数相关,温度敏感性系数Q_(10)值大小为自养呼吸(3.40)异养呼吸(2.90)土壤总呼吸(2.45);栓皮栎土壤总呼吸、自养呼吸、异养呼吸速率与0 10 cm土壤体积含水量均显著线性相关;土壤总呼吸、自养呼吸速率与0 10 cm土壤电导率显著相关。土壤总呼吸和异养呼吸的温度敏感系数Q_(10)值均在冬季最大,夏秋季最小;而自养呼吸的Q_(10)值则呈相反的变化趋势。栓皮栎人工林自养呼吸和异养呼吸对土壤总呼吸的月贡献率为13.23%37.33%和62.67%86.76%,且自养呼吸的贡献率与土壤温度的季节变化规律相似。土壤总呼吸、异养呼吸与自养呼吸的CO2年通量分别为1 616.41、1 199.39、417.02 g·m~(-2)·a~(-1)。[结论]经过区分与定量化土壤总呼吸及其组分,确定异养呼吸为本研究区栓皮栎人工林土壤总呼吸的主要组分,作用于异养呼吸的生物与非生物因子均能显著影响整个森林生态系统表层CO_2总排放通量的大小,进一步为该研究区森林生态系统碳循环与能量流动的进一步量化研究提供参考。 相似文献