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1.
裂叶沙参与泡沙参种群分布格局分形特征的分析   总被引:23,自引:0,他引:23       下载免费PDF全文
 裂叶沙参与泡沙参种群在不同海拔区域分布格局的计盒维数与其在群落中占据空间的能力成正比,并且与环境因素密切相关。在裂叶沙参与泡沙参种群较为适生的区域,海拔2700~3100m,两者在群落中占据空间的能力最强,他们的计盒维数达到最高。在低于海拔2700m或高于海拔3100m,环境条件严酷的区域,裂叶沙参种群与泡沙参种群占据空间的能力不同程度的下降。在不同的海拔区域,广布种泡沙参种群占据空间的能力均比裂叶沙参种群高,而其受环境因素影响较弱。在海拔2700m以下地区,泡沙参种群水平分布格局的计盒维数比裂叶沙参种群高4.5倍;在两种群较为适生的区域,海拔2700~3100m,泡沙参计盒维数比裂叶沙参种群高1.5倍,差异最小;在泡沙参与裂叶沙参种群分布的上限,海拔3100m以上地区,两者计盒维数差异又增加,泡沙参计盒维数比裂叶沙参种群高1.8倍。这说明裂叶沙参种群的内在适应力、竞争力比泡沙参种群相对较弱。  相似文献   

2.
 基于构件理论,采用灰色关联度分析技术,对四川缙云山1989年风灾迹地林窗内大头茶(Gordonia acumenata)幼苗种群构件结构及其与环境因子的关系进行了研究。结果表明,四川缙云山大头茶幼苗种群构件结构主要分为一级枝、二级枝、当年生枝、空间结构、叶片等几大部分。分别可以以一级枝数或茎粗或长度、二级枝数或茎粗或长度、当年生枝数、3年生一级枝数、总叶数等的变化特征来表达其动态特点。前四者间的相关性亦很高,后者(包括主茎上叶面积)和主茎上第一级枝离地面高、主茎上第一叶距地高为比较稳定的特征,受其它生态因子作用影响不十分显著。相对而言,土壤全N、全P、全K、有机质含量及其pH值是比较关键的环境因子;而海拔高度和林窗大小及地形坡度却比较次要。灰色关联度分析不失为一种比较简捷而有效的分析植物种群构件结构特征间及与环境因子间关系的方法。  相似文献   

3.
太白红杉顶芽与分枝格局的适应性分析   总被引:3,自引:1,他引:2  
王孝安  赵相健 《生态学报》2004,24(11):2616-2620
野外调查发现太白红杉 (L arix chinensis)枝条顶芽死亡比例较高 ,顶芽死亡对分枝格局产生较大影响 ,可形成 3种分枝类型 : 型、 型和 型。对 3种分枝类型枝条的芽数量、计盒维数以及植冠不同部位的分枝类型比例、顶芽死亡比例、主侧枝平均枝长和主侧枝总数量分别进行了统计分析。结果显示 ,芽数量 : 型 (115 .3) < 型 (15 4 .8) < 型 (2 0 9.9) ;计盒维数 : 型(1.30 5 ) < 型 (1.4 0 0 ) < 型 (1.5 37) ;顶芽死亡比例由树冠上层至下层逐渐提高 ,而冠层东南西北 4个方向的顶芽死亡比例无显著差异 ;主侧枝平均枝长由树冠上层至下层逐渐增加 ,而主侧枝总数量则逐渐降低 ;由于风、光照、坡度和坡向的影响 ,冠层4个方向间的主侧枝平均枝长和总数量均存在显著差异 ; 型分枝使植冠半径扩大 , 型分枝快速扩展植冠的横向空间 , 型分枝在扩展空间的基础上并实现对空间的有效占据。研究表明太白红杉枝条中一定比例的顶芽死亡增加了分枝形态的多样性 ,表现出顶芽和分枝格局的环境适应性 ,有利于提高树冠的空间占据能力  相似文献   

4.
云雾山自然保护区优势植物种群分布格局的分形特征   总被引:3,自引:0,他引:3  
李鹏远  程积民  万惠娥  彭少邦  景艳 《生态学报》2008,28(10):5161-5165
对宁夏云雾山草原自然保护区植物种群分布格局的分形计盒维数进行了研究。结果表明:本氏针茅、铁杆蒿和百里香是该区的优势种。3种优势种的计盒维数在1.7左右,表明它们具有较大的空间占据能力。但是它们的计盒维数最大值出现的时间不同,本氏针茅、百里香计盒维数最大值出现存封育20a的样地中,铁杆蒿出现在封育25a的样地中。  相似文献   

5.
元宝山南方红豆杉克隆种群分布格局的分形特征   总被引:1,自引:0,他引:1       下载免费PDF全文
 南方红豆杉(Taxus chinensis var.mairei)是提取抗癌药物紫杉醇的珍贵资源植物。分布于广西元宝山自然保护区的南方红豆杉,自然状态下 以克隆繁殖方式进行种群更新,研究其种群克隆生长的空间分布格局,可揭示种群克隆繁殖特性和生态适应机制,对南方红豆杉这一珍稀濒危 物种的保护和管理具有重要意义。利用分形理论中的计盒维数和信息维数,对元宝山的南方红豆杉克隆种群空间分布格局的分形特征进行了分 析,结果表明:种群空间分布格局存在分形特征,其计盒维数介于0.993 1~1.353 1之间,信息维数介于1.350 8~1.652 1。南方红豆杉克隆 种群格局的计盒维数远离最大理论维数值2,种群总体对空间的占据能力较弱。克隆构型指数与种群计盒维数密切相关。分析结果显示,克隆构 型趋于“密集型”的种群具有较强的空间占据能力,而克隆构型趋于“游击型”的种群其空间占据能力较弱。信息维数与种群的集聚强度密切 相关,其差异反映了种群格局强度的变化,较大的信息维数反映种群个体的集聚强度较高,而较小的信息维数则反映出种群个体间的集聚强度 较弱,其维数值大小与分株种群数量、分株种群斑块的空间配置密切相关。  相似文献   

6.
云贵鹅耳枥种群分布格局的分形特征   总被引:14,自引:2,他引:12  
应用分形理论中的计盒维数和信息维数探讨了贵阳喀斯特山地贵鹅耳枥种群分布格局的分形特征。结果表明,贵鹅耳枥种群的分布格局具有分形特征,其计盒维数为1.1853-1.7419,信息维数为1.1961-1.7051。集群型的贵鹅耳枥种群的计盒维数和信息维数均比随机型的高。计盒维数定量地反映了贵鹅耳枥种群占据生态空间的能力,信息维数则揭示了该种群格局强度的尺度变化程度和表征了种群个体分布的非均匀性。这两种维数方法都适用于贵鹅耳枥种群分布格局分形特征的定量描述。  相似文献   

7.
为摸清提前钩梢对雷竹地上构件生物量积累与分配及其异速生长模式的影响,为雷竹林合理钩梢提供参考,调查了5月(提前钩梢)、6月(常规时间钩梢)钩梢和未钩梢雷竹林新竹当年(1年生立竹)和第2年(2年生立竹)秆、枝、叶生物量,分析了立竹地上构件生物量积累与分配特征及其异速生长。结果表明:钩梢使雷竹1年生立竹秆、枝、叶生物量显著下降,秆生物量分配比例显著升高,枝、叶生物量分配比例显著下降,枝、叶-总生物量异速生长指数显著增大,秆-总生物量异速生长指数显著减小,且常规时间钩梢立竹叶生物量及其分配比例和出叶强度均显著高于提前钩梢立竹。钩梢也导致雷竹2年生立竹秆、枝、叶生物量明显下降,但秆、枝、叶-总生物量异速生长指数均显著增大,常规时间钩梢立竹叶生物量仅略低于未钩梢立竹,且叶生物量分配比例及出叶强度均显著高于未钩梢和提前钩梢立竹。研究表明提前钩梢对雷竹叶生物量及其分配比例、出叶强度及异速生长均有明显的负面影响,不利于雷竹林光合能力的发挥,因此,雷竹林不宜提前钩梢。  相似文献   

8.
黑松不定芽的增殖   总被引:1,自引:0,他引:1  
以无菌条件下萌发22 d的黑松幼苗子叶/胚轴材料为起始外植体,在GD 3 mg·L~(-1)6-BA 0.3 mg·L~(-1)NAA培养基中诱导黑松不定芽的形成,其诱导率为96%。进一步探讨生长调节物质水平、基本培养基种类和继代周期对黑松不定芽增殖影响的结果表明:6-BA浓度为2 mg·L~(-1)、NAA浓度为0.2 mg·L~(-1)时的增殖率最高,达100%,增殖倍数也最高,为4.88;在5种基本培养基(GD、DCR、WPM、1/2MS和1/2GD)中,GD培养基比较适合不定芽的增殖,可以形成健壮有效的不定芽;此种条件下培养30 d的黑松不定芽增殖率可达4.6倍。  相似文献   

9.
兴安落叶松种群格局的分形特征:计盒维数   总被引:37,自引:1,他引:36  
分形维数是分形体填充空间程度的度量 ,种群格局计盒维数能够揭示出种群格局的空间占据程度及其尺度变化规律 ,拐点尺度指示出个体聚集尺度。本文应用计盒维数对大兴安岭主要森林类型中兴安落叶松种群空间格局进行的研究表明 ,兴安落叶松种群格局均具有统计自相似性。各类兴安落叶松林中兴安落叶松种群格局具有较高的计盒维数 ( >1 .5 ,接近 2 ) ,对空间占据程度较高 ,建群和优势地位明显 ,空间占据程度的强弱次序为越桔—兴安落叶松 ( 1 .82 9) >草类—兴安落叶松林 ( 1 .72 0 ) >杜鹃—兴安落叶松 ( 1 .70 5 )杜香—兴安落叶松林 ( 1 .5 1 3)。兴安落叶松—白桦林中 ,兴安落叶松处于劣势伴生地位 ,种群格局的计盒维数较低 ( 1 .371 ,远离2 ) ,空间占据程度低。通过对天然森林类型中兴安落叶松种群格局的计盒维数与兴安落叶松人工林的比较发现 ,兴安落叶松种群空间占据程度由高至低的次序为兴安落叶松人工林 ( 1 .86 8) >兴安落叶松天然林 ( 1 .6 92 ) >兴安落叶松—白桦林 ( 1 .371 ) ,揭示出兴安落叶松种群在不同森林类型中地位和作用的差异。  相似文献   

10.
辽东栎芽库统计:芽的命运   总被引:10,自引:3,他引:7  
孙书存  陈灵芝 《生态学报》2001,21(3):385-390
植物体是一个构件集合体,植物的枝系伸展可由芽库出生率、死亡率的统计学过程来分析。在东灵山地区,应用随机枝取样法调查了辽东栎芽的命运,并对其与枝长、叶数、果数等的关系进行了统计分析。结果表明:(1)辽东栎的芽或保持休眠状态,或死亡后脱落,或分化为营养枝、生殖枝(包括雄花枝、雄花序、雌花枝和两花枝)等;(2)不同生境中芽的命运不同,生活在林窗中的幼树上的芽分化为具有生殖功能的枝条的比例显著高于郁闭林中的幼树,而与成熟个体接近;(3)芽的命运还受其它因子的影响,如上层枝条上、或叶数多的长枝上的芽分化为生殖枝的可能性大于其它的芽,另外还发现结实枝的枝长、枝上叶数都明显高于非结实枝。  相似文献   

11.
Insect herbivory can negatively or positively affect plant performance. We examined how a stem gall midge Rabdophaga rigidae affects the survival, growth, and bud production of current year shoots of the willow Salix eriocarpa. In mid-May, the gall midge initiates stem galls on the apical regions of shoots. The following spring, galled shoots had thicker basal diameters and more lateral shoots than ungalled shoots. Although galled shoots were on average 1.6 times longer than ungalled shoots, there were no significant differences in shoot length or in the numbers of reproductive, vegetative, and dormant buds per shoot. However, the subsequent survival of galled shoots was significantly higher than that of ungalled shoots, probably because of the thicker basal diameter. This increased shoot survival resulted in approximately two times greater reproductive, vegetative, and dormant bud production on galled shoots compared with ungalled shoots in the following spring. These results suggest that the willow regrowth induced by galling can lead to an increase in bud production through increased shoot survival.  相似文献   

12.
To examine plastic willow regrowth response to herbivory, we studied the effect of a boring insect, the swift moth Endoclita excrescens (Hepialidae: Lepidoptera), which does not remove apical meristems, on shoot growth in three willow species—Salix gilgiana, S. eriocarpa, and S. serissaefolia−by direct observations and experiments in the field. We hypothesized that the stem-boring could initiate new lateral bud activation, and result in secondary shoot regrowth without the removal of the primary apical meristems. There were significantly more lateral shoots on naturally attacked than unattacked stems, and a significant positive correlation between lateral shoot density and the number of swift moth tunnels per tree was observed for all three willow species. Artificial boring, and larval infestation, resulted in an increase in the number of lateral shoots, but did not affect growth of current-year shoots. The length of lateral shoots differed between species, being significantly longer in S. gilgiana than S. eriocarpa and S. serissaefolia. The results of this study show that compensatory regrowth can result even if herbivory does not remove the apical meristem. We argue that this type of plant compensatory response is probably widespread, given that the stem-boring is a common feeding type of insect herbivores.  相似文献   

13.
J. B. Fisher 《Planta》1971,97(3):257-268
Summary The axillary buds in the leaf crown of Cyperus alternifolius seedlings remain completely inhibited although the shoot is determinate and has no active apex. Buds can be released by detachment of the crown from the plant or by direct application of aqueous enzyladenine (BA), and grow out as inflorescences or vegetative shoots. These arise from activated growth centers of the primordial reproductive branch system which is enclosed within the prophyll of the inhibited bud. Buds are also released by the growth retardant, (2-chloroethyl) trimethylammonium chloride (CCC). Gibberellic acid maintains bud inhibition in detached crowns and inhibits bud release caused by CCC or BA. Naphthaleneacetic acid somewhat reduces BA-induced bud release and causes abnormal root proliferation in CCC-treated crowns. It is suggested that a high level of gibberellin within the crown, possibly in relation to a low level of cytokinin, maintains bud inhibition.  相似文献   

14.

Backgrounds and Aims

Shoot demography affects the growth of the tree crown and the number of leaves on a tree. Masting may cause inter-annual and spatial variation in shoot demography of mature trees, which may in turn affect the resource budget of the tree. The aim of this study was to evaluate the effect of masting on the temporal and spatial variations in shoot demography of mature Betula grossa.

Methods

The shoot demography was analysed in the upper and lower parts of the tree crown in mature trees and saplings over 7 years. Mature trees and saplings were compared to differentiate the effect of masting from the effect of exogenous environment on shoot demography. The fate of different shoot types (reproductive, vegetative, short, long), shoot length and leaf area were investigated by monitoring and by retrospective survey using morphological markers on branches. The effects of year and branch position on demographic parameters were evaluated.

Key Results

Shoot increase rate, production of long shoots, bud mortality, length of long shoots and leaf area of a branch fluctuated periodically from year to year in mature trees over 7 years, in which two masting events occurred. Branches within a crown showed synchronized annual variation, and the extent of fluctuation was larger in the upper branches than the lower branches. Vegetative shoots varied in their bud differentiation each year and contributed to the dynamic shoot demography as much as did reproductive shoots, suggesting physiological integration in shoot demography through hormonal regulation and resource allocation.

Conclusions

Masting caused periodic annual variation in shoot demography of the mature trees and the effect was spatially variable within a tree crown. Since masting is a common phenomenon among tree species, annual variation in shoot demography and leaf area should be incorporated into resource allocation models of mature masting trees.  相似文献   

15.
The architectural development ofViburnum dilatatum andV. wrightii was investigated quantitatively. In both species, the major axis is developed from terminal buds of vegetative shoots and from axillary buds on the most distal nodes of reproductive shoots. The architecture of the two species is formed mainly by four branching patterns: a monopodial pattern (M), a sympodial pattern producing a pair of opposite daughter shoots (SP), a sympodial pattern producing a single daughter shoot (SS), and a pattern terminated with a dormant or dead bud (D). In the process of the architecture formation, four successive stages are recognized: 1) height growth, where the M pattern is dominant; 2) crown formation, in addition to the M pattern, the SP pattern occurs frequently; 3) crown expansion, the M and SP patterns are also frequent; 4) over mature, the M pattern becomes dominant again. These four stages are common to the two species, butViburnum wrightii proceeds with the crown formation stage more rapidly and stays in the crown expansion stage for a longer time thanV. dilatatum. The crown ofViburnum wrightii is thus more branched than that ofV. dilatatum.  相似文献   

16.
Developmental preformation can constrain growth responses of shoots to current conditions, but there is potential for flexibility in development preceding formation of the preformed organs. Mayapple (Podophyllum peltatum) is strongly heteroblastic, producing rhizome scales, bud scales, and either a single vegetative foliage leaf or two foliage leaves on a sexual shoot. To understand how and when preformation constrains growth responses, we compare (1) how leaf homologs of the renewal shoot differ in development, (2) whether there are differences in shoot development that occur in advance of morphological determination of shoot type, and (3) whether there are points of developmental flexibility in renewal shoot growth prior to preformation of the foliage and floral organs. We use scanning electron microscopy and histology to show that the three vegetative leaves (both types of scale leaves and the vegetative foliage leaf) are similar in the initial establishment of an encircling and overarching leaf base. Differences among them are found in the timing of differentiation of the leaf base and in the relative timing and degree of growth of the lamina and petiole. In contrast, foliage leaves on sexual shoots show less expression of the leaf base and precocious growth of the lamina and petiole. Prior to shoot type determination, there are no morphological differences in the sequence or position of leaf homologs that predict final shoot type. In this colony, leaves at positions 12 and 13, on average, appear to be identical in development until they are between 700 and 800 μm in length, when it becomes possible to distinguish leaves that will become vegetative foliage leaves from additional bud scale leaves on vegetative or sexual shoots. We suggest that late developmental determination of leaves at positions 12 and 13 reflects ontogenetic sensitivity to a transition to flowering. Thus, in mayapple, heteroblasty appears to facilitate developmental flexibility prior to the point where shoot growth becomes constrained by preformation of determined aerial structures.  相似文献   

17.
Leaf and bud demography and shoot growth were studied in 10 evergreen (ES) and 15 deciduous (DS) tree species occurring between 600 and 2200 m elevation in the central Himalayan mountains in India. Results were analyzed to help explain why ES prevail in the vegetation of this region, even though the number of ES is no greater than for DS. Although each species had its own pattern with regard to leaf and bud demography and seasonality of shoot extension and radial growth, it was possible to group the species on the basis of shoot growth phenology. In most species, leaves emerged during March-April, at the onset of warm and dry summer season. The ES recruit leaves in shoots more rapidly than the DS. Across all species, peak number of leaves per shoot (5.8–20.7), peak leaf area per shoot (116.2–1559.2 cm2), peak number of vegetative buds per shoot (1.9–14.5), bud survival per shoot (23–84%), shoot extension growth (6.4–40.8 cm) and shoot extension period (13–30 weeks) varied considerably. The peak leaf area per shoot (587.7 vs. 246.7 cm2) and shoot extension growth (19.3 vs. 11.2 cm) were significantly greater for DS than for ES, and these two functional groups of species were clearly separable with regard to shoot growth characteristics.Results indicate that rapid recruitment of leaf crop in the shoots, longer leaf life-span, and access to ground water due to deep roots were some of the advantages, the ES had over the DS, that may have likely enable them to maintain growth for a longer period in this region of warm winters and longer winter day length as compared to temperate climates. In the shallow rooted DS, shoot growth seems to be much affected by a seasonal drought in winter and they are likely to be affected more in the event of failure of monsoon rains in this region.  相似文献   

18.
The effects of simulated herbivory (early or late defoliation and cutting of the flowering shoot) on the growth and reproduction of three species of monocarpic composite forbs (Crepis pulchra, Picris hieracioides and C. foetida) with different inflorescence architectures were studied in experimental plots. For the three species studied, early defoliation had no significant effect on subsequent growth. In contrast, late defoliation, occurring at the start of the season of drought, had a negative effect on growth and reproduction in the two Crepis species, particularly C. foetida, but had less effect on P. hieracioides. Sexual biomass was more clearly affected by late defoliation than was vegetative biomass, although the effects differed markedly among species possibly as a result of differences in phenology. Clipping the flowering shoot removed about 3 times less biomass than late defoliation and had little effect on vegetative biomass. It had much greater effects on the sexual biomass in P. hieracioides and C. pulchra, and resulted in the production of many shoots sprouting from the rosette, allowing the treated plants to regain a vegetative biomass close to that of control plants. Clipping did however lead to the production of shorter shoots and a reduction in the number of capitula formed. In C. foetida, much branching occurred even when the main shoot was not cut; the architecture of individual plants was therefore only slightly changed by clipping the apical bud and the sexual biomass of this species was not affected by ablation of the flowering shoot. Overcompensation was found in only two families of C. pulchra for vegetative biomass. No over-compensation was found for sexual biomass, despite an increase in the number of flowering shoots in C. pulchra and P. hieracioides following clipping. However situations close to compensation for the vegetative biomass in the three species and in P. hieracioides for the sexual biomass were recorded. The response of the three study species to simulated herbivory were related to their architecture and to the time of defoliation.  相似文献   

19.
BACKGROUND AND AIMS: Plants have complex mechanisms of aerial biomass exposition, which depend on bud composition, the period of the year in which shoot extension occurs, branching pattern, foliage persistence, herbivory and environmental conditions. METHODS: The influence of water availability and temperature on shoot growth, the bud composition, the leaf phenology, and the relationship between partial leaf fall and branching were evaluated over 3 years in Cerrado woody species Bauhinia rufa (BR), Leandra lacunosa (LL) and Miconia albicans (MA). KEY RESULTS: Deciduous BR preformed organs in buds and leaves flush synchronously at the transition from the dry to the wet season. The expansion time of leaves is <1 month. Main shoots (first-order axis, A1 shoots) extended over 30 d and they did not branch. BR budding and foliage unfolds were brought about independently of inter-annual rainfall variations. By contrast, in LL and MA evergreen species, the shoot extension rate and the neoformation of aerial organs depended on rainfall. Leaf emergence was continuous for 2-6 months and lamina expansion took place over 1-4 months. The leaf life span was 5-20 months and the main A1 shoot extension happened over 122-177 d. Both evergreen species allocated biomass to shoots, leaves or flowers continuously during the year, branching in the middle of the wet season to form second-order (A2 shoots) and third-order (A3 shoots) axis in LL and A2 shoots in MA. Partial shed of A1 shoot leaves would facilitate a higher branching intensity A2 shoot production in LL than in MA. MA presented a longer leaf life span, produced a lower percentage of A2 shoots but had a higher meristem persistence on A1 and A2 shoots than LL. CONCLUSIONS: It was possible to identify different patterns of aerial growth in Cerrado woody species defined by shoot-linked traits such as branching pattern, bud composition, meristem persistence and leaf phenology. These related traits must be considered over and above leaf deciduousness for searching functional guilds in a Cerrado woody community. For the first time a relationship between bud composition, shoot growth and leaf production pattern is found in savanna woody plants.  相似文献   

20.
To elucidate the significance of the simultaneous growth of vegetative and reproductive organs in the prostrate annual Chamaesyce maculata (L.) Small (Euphorbiaceae) from the standpoint of meristem allocation, we investigated plant architecture, meristem allocation, and the spatial and temporal patterns in vegetative growth and reproduction in the reproductive stage. The numbers of secondary and tertiary shoots successively increased by branching in the reproductive stage, and the sum of shoot length was greater in secondary shoots than in primary shoots. The specific shoot length (shoot length per shoot biomass) was greater in lateral shoots than in primary shoots, indicating efficient lateral shoot elongation. The internode length was shorter in secondary shoots than in primary shoots, increasing the number of nodes per shoot length in secondary shoots. Many nodes on a shoot generated two meristems, one of which committed to a flower and one to a lateral shoot. The number of reproductive meristems was greatest in tertiary shoots, and 96% of total reproductive meristems on shoots were generated in lateral shoots. On almost all nodes, the reproductive meristem developed into a flower, and 95–98% of the flowers produced a fruit. Therefore, vegetative growth by branching in the reproductive stage contributed to the increase in reproductive outputs. From the standpoint of meristem allocation, the simultaneous growth of vegetative and reproductive organs in prostrate plant species might be important for increasing the number of growth and reproductive meristems, resulting in the increase in reproductive outputs.  相似文献   

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