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生命表、存活曲线和生存分析是研究种群动态的重要工具,其关键就是科学正确地划分龄级。该文研究了水灾迹地不同龄级划分方法对油松(Pinus abulaeformis)和华山松(P. armandii)种群存活曲线和生存分析函数曲线的影响。华山松以实际年龄作为龄级划分指标时,存活曲线为Ⅱ型;地径和树高作为划分指标时,存活曲线为Ⅲ型。生存函数和累计死亡率函数也发生类似的类型变化。油松实际年龄、地径和树高作为龄级的划分指标时,存活曲线(Ⅱ型)、生存率函数和累计死亡率函数类型一致,均为直线型。死亡率函数和危险率函数在不同树种和不同龄级划分方法间不存在明显差异。因此,华山松地径和树高作为龄级划分的代用指标不可行,而油松可行。其主要原因是华山松树高和地径与年龄的关系为指数函数关系,而油松则为直线函数关系。在此基础上把华山松地径和树高取自然对数后重新划分龄级,则存活曲线关系在地径、树高和实际年龄之间不存在差异,均为Ⅱ型。从而得出结论,地径、树高和年龄之间线性关系与否是地径和树高作为实际年龄代用指标可行性和准确性的关键。因此,在植物种群统计研究中,大小作为龄级划分代用指标要慎用。在未来研究中,种群个体年龄和大小关系及其影响因素的研究对植物种群数量动态分析和种群统计学的发展具有重要意义。 相似文献
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This paper emphatically deals with the ultrastructure of albuminous cells in different stages of development in the secondary phloem of Pinus bungeana. The secondary phloem of Pinus bungeana is composed of sieve cells, axial parenchyma cells, radial plates and rays. Among the constituents, most of upright ray cells and radial plate parenchyma cells are albuminous cells. Although the shape and distribution of this kind of albuminous cells may be different, they possess the following common cytological characteristics. These cells have dense cytoplasm with abundant mitochondria, ribosomes, rough endoplasmic reticula and a large nucleus, the nuclei of some albuminous cells are lobed in shape which increases the outer surface of the nuclei. Usually the albuminous cell contains some starch granules, the quantity of the starch granules in albuminous cells is less than the other parenchyma cells of the secondary phloem. All these cytological characteristics suggest that albuminous cells are active physiologically. The distinguishing characteristics of albuminous cells from other parenchyma ceils are that the albuminous cells are associated with sieve cells through unilateral sieve area and they died together with the sieve cells. 相似文献
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白皮松绒毡层细胞超微结构的研究 总被引:4,自引:1,他引:4
白皮松绒毡层细胞的细胞器是十分丰富的,其中粗糙内质网、核糖体和造粉体在减数分裂过程中达到高峰。小孢子形成时,绒毡层细胞开始解体,内质网和线粒体是最后衰老的细胞器。在单核花粉形成时,处于绒毡层细胞外切向壁上的周绒毡层膜特别明显。但是,孢粉素体却主要分布在内切向壁和径向壁上。有趣的是,绒毡层细胞中的造粉体结构与壁层细胞不同。而且,脂体在二分体阶段基本消失,相反,此刻孢粉素体却在质膜外大量聚集。推测脂体的消长可能与原乌氏体和孢粉素体的形成有关。 相似文献
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This paper deals with structures of the secondary phloem of Pinus bungeana Zucc. The sieve cells lived for only one growing season. Most of them formed in spring and summer and then died in the end of winter. However, some of them formed in autumn and died eventually in the end of next spring. Two types of albuminous cells: type A and type B were seen in radial plates and rays, which possessed the following common characteristics, there were unilateral sieve area connections between these and the sieve cells. These cells had larger nuclei, denser cytoplasm with abundant mitochondria and rich RNA-protein. Their death closely followed that of the sieve cells. Type A albuminous cells differed from type B in that the former collapsed before the contents of sieve cells accompanied with it dissppeared. But, type B did not collapse until complete disappearance of the contents of sieve cells. The cytological characteristics of albuminous cells, the relationship between radial plates and rays, and possible physiological significance are also disscussed. 相似文献
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为更好地恢复和保存白皮松天然林,在陕西省白皮松残存林地采集根际土壤,采用幼苗检测法获取土壤外生菌根真菌繁殖体,用形态观察分类与ITS-PCR-sequencing相结合的方法进行菌根鉴定,研究白皮松林地外生菌根真菌土壤繁殖体库的组成.结果表明: 在白皮松幼苗菌根中共获得73个特异性序列;按照97%的相似度阈值,将序列划分为12个可操作分类单元(OTUs);稀疏曲线分析表明,本研究基本获得了白皮松土壤外生菌根繁殖体库的多样性.常见种有土生空团菌、Tomentella sp.、Tuber sp.等.出现频率最高的一个OTU(80%)与已知种类相似度较低(75%),说明其可能是一个新的菌根菌种类.白皮松残存天然林地的外生菌根繁殖体库中具有其他松科植物土壤繁殖体库常见的种类,但是频率最高的种类未能鉴定到已知属或科,说明白皮松菌根繁殖体库具有其宿主特异性.这种群落特异构成也说明研究和利用白皮松土壤外生菌根真菌繁殖体库具有特殊性和重要性. 相似文献
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Except for Pseudolarix, which is endemic to China, the late embryogeny of tengenera of Pinaceae has been reported before in the diffferent degree. Among them the matureembryos of Keteleeria evelyniana are different from those of the others in having well-developedcotyledons and a very short hypocotyl. As far as information we have is concerned there arethree types in structure of the mature embryos of Pinaceae. The first type occurs in Keteleeriaand Cedrus, which have very well-developed cotyledons; the second one appears in Picea andLarix, in which the hypocotyl and the root cap are equal in length; the third one, to whichPinus bungeana belongs, includes all the other genera of Pinaceae. The last type is of a prominent hypocotyl in the mature embryos. It is interesting to note that the mature embryos of Torreya grandis and Keteleeria evelyniana are very similar in having specially developed cotyledons, while the proportions of the various tissues in the mature embryo in Fokienia of Cupressaceae as well as Taxus and Amentotaxus of Taxaceae are similar to those of Pinus bungeana.The pith and secretory cells are usually present in the mature embryos of Pinaceae. Althoughno pith is present in those of Metasequoia and Taiwania of Taxodiaceae, the secretory cells generally occur in their embryos in Fokienia of Cupressaceae and Taxus and Pseudotaxus of Taxaceae, neither pith nor secretory cells are present in their hypocotyl. From above, the structures of mature embryos among Pinaceae, Taxodiaceae and Cupressaceae are different from oneanother to some degree. The most outstanding feature of the matur embryos in Pinus bungeana is that the shootapex is very well developed, with a high H/D ratio, about 0.83 on an average, even up to 0.96in some case. Above-mentioned H/D ratio of Pinus bungeana is rare in the mature embryos ofconifers. Gifford (1943) reports that the average H/D ratio of shoot apex of Ephedra altissimais from 0.44 to 0.68, while in 5-year-old branch apex of Pinus ponderosa, the average ratio isabout 0.25, and that in l5-year-old branch apex is about 0.35. For the apex of the dormantshort shoots of Pinus densiflora the average ratio is about 0.35, but that of shoot apex is about0.52 when new buds have just formed. According to the present data about shoot apices of bothbranches and mature embryos, the average ratio of shoot apex of mature embryos in Pinus bungeana is the largest one. From the present investigation the shoot apex of mature embryos ofPinus bungeana exhibits four distinct tissue zones, i.e. the apical initials, the central mother cellzone, the peripheral tissue zone and the rib meristem. It is worthy of note that the shoot apexof Pinus strobus may be divided into five zones, including transition zone between central mothercells and rib meristem (Owston, 1968). Four zones are recognized in the shoot apex ofPinus lambertiana and P. ponderosa, without transition one (Sacher, 1954). From cytologicalzonation, the shoot apex of mature embryos in Pinus bungeana is rather similar to that of Pinuslambertiana and P. ponderosa. 相似文献
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甘肃省小陇山濒危珍稀植物白皮松群落种间关联 总被引:2,自引:0,他引:2
通过野外调查,选取小陇山白皮松群落50个样方的20个常见物种,运用多物种方差比值(VR),χ2检验,OI、DI、JI指数,AC、PC值以及Pearson相关系数和Spearman秩相关系数对其进行了种间关联分析。VR分析表明,白皮松林主要组成成分间的关系以正关联为主,说明白皮松群落的性质与其生存环境特征是一致的,白皮松林适应群落外环境;20个常见种种对关系表现出了不同的性质,是群落内环境的表现,也是由群落内环境异质性所致;综合植物的生态特征,划分出3个生态种组,发现白皮松群落的高负关联性是由林下喜阴灌木引起的,而群落较高的独立性则是由林缘植物引起的。种间关联的研究可以反映出由物种生态特征所形成的有机联系,研究结果对白皮松群落的保护与恢复有一定的指导意义。 相似文献
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蛋白酶体途径对花粉发育调控具有重要作用, 但花粉发育过程中蛋白酶体的分布及其活性的动态变化一直未见报道。蛋白酶体荧光底物结合荧光分光光度计分析表明, 蛋白酶体的活性从单核小孢子到具有2个原叶细胞的三细胞花粉逐渐增强, 而在成熟花粉中略有下降。免疫荧光标记结合共聚焦显微镜分析表明, 蛋白酶体不均匀地分布于细胞质和细胞核中, 并在花粉细胞不均等分裂过程中聚集分布于先后产生的2个原叶细胞内。总之, 蛋白酶体的活性及其分布在花粉发育过程中存在相关的时空动态变化, 表明裸子植物花粉中的蛋白酶体活性及其分布与花粉发育具有相关性, 并在原叶细胞的退化过程中起重要作用。 相似文献
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白皮松的保育遗传学研究Ⅰ.基因保护分析 总被引:3,自引:0,他引:3
在白皮松主要分布区抽取了10个天然群体进行酶电泳分析,共测定了16种酶系统,得到31个清晰酶位点和53个等位基因。按照基因频率进行分类,53个基因中有32个全局基因、14个广域基因、6个局域基因和1个特异基因。通过计算机模拟建立基因捕获曲线的结果表明,随机抽取5个群体可平均捕获99.9%的基因。群体的等位基因频率与地理生态因子的相关分析表明,Idh与Pgi-2两个位点的基因频率呈现明显的梯度变异。该项研究为有效保护白皮松天然群体的基因资源提供了依据。 相似文献
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白皮松的保育遗传学研究I.基因保护分析 总被引:3,自引:0,他引:3
在白皮松主要分布区抽取了10个天然群体进行酶电泳分析,共测定了16种酶系统,得到31个清晰酶位点和53个等位基因。按照基因频率进行分类,53个基因中有32个全局基因、14个广域基因、6个局域基因和1个特异基因。通过计算机模拟建立基因捕获曲线的结果表明,随机抽取5个群体可平均捕获99.9%的基因。群体的等位基因频率与地理生态因子的相关分析表明,Idh与Pgi—2两个位点的基因频率呈现明显的梯度变异。该项研究为有效保护白皮松天然群体的基因资源提供了依据。 相似文献
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The essential-oil composition of Pinus peuce Griseb. is reported at the population level. Macedonian pine is endemic high-mountain Balkan pine relict of an anthropogenically reduced area, with large morphological diversity and insufficiently clear taxonomic position. In the pine-needle terpene profile of two populations from Montenegro and one from Serbia, 78 compounds were detected, 56 of which are identified (Table 3). The dominant constituents were alpha-pinene (36.5%) and germacrene D (11.4%). The following 20 additional components were found to be present in medium-to-high amounts (0.5-10%): camphene (8.5%), bornyl acetate (6.8%), beta-pinene (6.8%), beta-caryophyllene (5.2%), beta-phellandrene (4.7%), terpinen-4-ol acetate (1.6%), (E)-hex-2-enal (1.5%), alpha-muurolene (1.2%), beta-gurjunene (1.1%), beta-myrcene (1.0%), alpha-terpinyl acetate (0.9%), alpha-phellandrene (0.8%), delta-cadinene (0.8%), alpha-humulene (0.8%), sabinene (0.7%), aromadendrene (0.6%), alpha-thujene (0.6%), gamma-muurolene (0.6%), gamma-cadinene (0.6%), alpha-terpinolene (0.5%), and one unknown component (0.5%). The similarity of the populations and the within-population variability were visualized by principle-component analysis (PCA) and genetic analysis of selected terpenes in 90 tree samples. Our study suggests a closer connection between populations II and III compared to population I. Based on the profile of the main terpene components, the studied populations are more similar to populations from Kosovo and Greece than to the population from Mt. Mokra (Montenegro) and the population in France. 相似文献
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HONG De-Yuan 《植物分类学报:英文版》1998,36(6):538-543
The history of exploration and classification of Paeonia rockii is reviewed in thepresent paper. Two allopatric subspecies in this species are recognized. The new subspecies,subsp, taibaishanica Hong, found on northern slope of the Qingling Range has leaflets ovateor rounded, totally or mostly lobed. P. rockii subsp, linyanshanii T. Hong et G. L. Ostiis found to be a superfluous name of P. rockii subsp, rockii. 相似文献
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白皮松和油松雌配子体愈伤组织的诱导和分化 总被引:11,自引:0,他引:11
以白皮松(Pinus bungeana Zucc.)和油松(P.tabulaeform is Carr.)的未成熟胚乳,即雌配子体为外植体进行培养,将雌配子体分别接种在添加不同激素种类和不同浓度配比的改良MS培养基上诱导愈伤组织。经过20多天的培养,在含有1—6 m g/L 萘氧乙酸(NOA)和0.5m g/L6-BAP及3% 蔗糖浓度的培养基上诱导产生了愈伤组织,愈伤组织的诱导频率最高为25% 。经细胞学观察证明:愈伤组织细胞确为单倍性的,染色体数目为n= 12,正常的体细胞染色体数目为2n= 24,并在含有ABA 的原诱导愈伤组织培养基上分化出绿色小芽 相似文献