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1.
峨参无性萌芽构件的空间格局研究及环境解释 总被引:1,自引:0,他引:1
用Ward聚类法按不同的群落环境类型将峨参的群落类型划分成4类;萌芽在所有区组都为集群分布,且所有样地中0.002区组、个别样地的其他区组(0.005和0.01)符合理论拟合随机分布,在环境和自身生物学特性上得到了解释。峨参萌芽构件的空间格局对群落环境有强烈的响应:典范对应分析(CCA)累积解释环境量为64.7%,发现峨参在群落尺度上或更小范围内应以光照条件和腐殖质层厚度(养分)为主。 相似文献
2.
Li Pengfei Zhang Ximing Hui Enxian Liu Zhifang Ge Yuxiang Wang Jun Wang Daojun Wu Changyou 《林业研究》1998,9(4):264-268
The spatial distribution pattern of needle bright disease was mathematically studied. The results showed that it is tally
with negative binomial distribution. The infected area and damaged amount can be forecasted with this spatial distribution
pattern. Through the study on probability distribution of spatial points for single tree, the method and equations for calculation
of the disease index of whole forest belt were determined.
(Responsible Editor: Chai Ruihai) 相似文献
3.
Yunchun Zhang Xiaojun Du Qiaoying Zhang Xianming Gao Zhixian Su 《Frontiers of Forestry in China》2006,1(2):142-149
There are two ways for Symplocos laurina to propagate: clonal reproduction and sexual reproduction. S. laurina adopted different ways to propagate and occupy space in different environments: under conditions with abundant water, nutrient
resources, and lower light such as in an evergreen broad-leaved or a bamboo forest; survival rates and the ability of both
clonal and sexual seedlings to occupy space, were relatively high. But clonal ramets took advantage both in terms of number
and space. Therefore, clonal propagation predominated in such an environment. However, in habitats lacking sufficient nutrition
and with higher light intensity, survival rates and space-occupying ability of two kinds of seedlings (sexual and asexual
produced) were low and the space would be preempted by grown-up plantlets. A bottleneck in sexual propagation appeared at
the stage from seed to seedling, while in clonal propagation it appeared during the period from an asexual plantlet to a ramet.
The way S. laurina invaded space was like that of a plantlet settled in a place and then occupied the space rapidly by clonal growth under conditions
of abundant water and nutrient resources and lower light such as in an evergreen broad-leaved forest or a bamboo forest. Clonal
seedlings showed a great advantage in the initial stages, but this advantage disappeared after 15 years.
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Translated from Chinese Journal of Applied Ecology, 2005, 16(9) [译自: 应用生态学报, 2005, 16(9)] 相似文献
4.
The spatial distribution of stolons ofWisteria floribunda DC. was investigated, and the ecological significance of clonal growth of this temperate liana is discussed. The study plot
(0.15 ha) was located in a secondary deciduous broad-leaved forest dominated byQuercus serrata in central Japan. The tree canopy was almost closed with a mean openness of 4.2%.W. floribunda was dominant among lianas accounting for 86% of their total basal area.W. floribunda stolons of three individuals branched numerous times and intersected among individuals, and showed a large horizontal “web-like”
extension on the ground. The total length of stolons was 66.0, 260.2, and 310.6 m, respectively, for each individual. A mean
of 25 ramets were established on stolons per individual, and one-third of the ramets obtained a host tree. These results suggested
that the expansion of stolons was effective in obtaining host trees forW. floribunda individuals. On the other hand, clonal growth ofW. floribunda did not always contribute to vertical growth of ramets in the study forest, since few ramets reached the forest canopy. Lack
of sub-canopy trees in this forest appeared to constrain the vertical growth ofW. floribunda ramets, since sub-canopy trees are thought to bridge lianas from smaller trees to canopy trees. 相似文献
5.
One 50 m × 50 m standard plot was sampled in a natural forest of Populus euphratica in Awati County, situated at the edge of the Tarim Basin, Xinjiang Uygur Autonomous Region, China. The field investigation
was conducted with a contiguous grid quadrate method. By means of a test of variance/mean value ratio, aggregation intensity
index and theoretical distribution models, the spatial distribution pattern and the dynamics of primary populations in P. euphratica forest were studied. The results showed that the spatial distribution pattern of two dominant arbor populations conformed
to clumped distribution. The aggregation intensity of the P. euphratica population was higher than that of P. pruinosa population. The spatial distribution pattern of two companion plant populations in the shrub layer also conformed to clump
type, though the aggregation intensity of Tamarix chinensis was higher. In the herb layer, the distribution patterns of Glycyrrhiza uralensis and Asparagus persicus conformed respectively to a clumped pattern and a random pattern. The results of a Taylor power method test and Iwao’s regression model also verified that both P. euphratica and P. pruinosa populations belong to a clumped pattern. Although the distribution pattern of P. pruinosa population at different development stages all belonged to a clumped distribution pattern, the aggregation intensity dropped
gradually along with age development. The distribution patterns of the P. euphratica population at different development stages changed from random type to clumped type, and further to random type. The differences
in spatial distribution patterns of different populations at different development stages were related not only to ecological
and biological characteristics of each species in the communities in the light of competitive exclusion principle among the
populations, but were also closely related to the habitats in which the species lived in.
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Translated from Journal of Southwest Forestry College, 2007, 27(2): 1–5 [译自: 西南林学院学报] 相似文献
6.
Spatial and environmental effects on plant communities in the Yellow River Delta, Eastern China 总被引:1,自引:0,他引:1
Types and structure of plant communities in the Yellow River Delta were investigated by using detrended canonical correspondence analyses (DCCAs) and a two-way indicator species analysis (TWINSPAN). The distribution pattern and influential factors of the plant communities were also analyzed by testing elevation, slope, soil characteristics, longitude and latitude of 134 vegetation samples collected by representative plot sampling methods. Results showed that all the 134 vegetation samples could be divided into seven vegetation groups, separately dominated by Robinia pseucdoacacia, Imperata cylindrical, Miscanthus saccharifleus, Suaeda salsa, Aeluropus sinensis, Phragmites australis and Tamarix chinensis. The vegetation distribution pattern was mainly related to elevation, ground water depth and soil characteristics such as salinity and soluble potassium. Among the factors affecting distribution pattern of the plant communities, the species matrix explained by non-spatial environmental variation accounts for 45.2% of total variation. Spatial variation and spatial-structured environmental variation explain 11.8%, and 2.2%, respectively. Remained 40.8% of undetermined variation is attributed to biological and stochastic factors. 相似文献
7.
8.
Based on the data collected from 27 plots of the Pinus armandii community in Qinling Mountains, we studied the spatial distribution pattern, scale, and gap characteristics of the P. armandii population. The results showed that the population had a clumped distribution before age 50. At the age range from 15 to
25, though the population tended to be distributed randomly, the distribution was still clumped. The population distribution
at the age range from 40 to 50 was at the transitional stage from clumped to random. After age 50, the population started
to be senesced, the distribution pattern turning from clumped to random. The distribution pattern scale of P. armandii always changes with the development stage of the population, being 100 m2 in general. The gap size of P. armandii population was similar to its distribution pattern scale, and the gaps of 80–130 m2 occupied 59% of the total. Because of the better light and nutrient condition in the gap, P. armandii seedlings grew well, which helped the population keep its stability through “mobile mosaic circling”.
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Translated from Chinese Journal of Ecology, 2006, 25(6): 652–656 [译自: 生态学杂志] 相似文献
9.
Softwood shoots were produced from 40 cm long stem segments placed horizontally in flat trays containing sterilized sand under natural light or shade conditions for subsequent rooting and micropropagation studies in teak (Tectona grandis L.). Higher number of shoots (6.17) per log was produced under natural light as compared to shade conditions. Forcing was also better in natural light as compared to shade in terms of shoot length, number of nodes or leaves. For rooting, 2–4 cm long softwood shoots were excised and treated with either indole-3-butyric acid (IBA) or α-naphthyl acetic acid (NAA) at 0, 1000, 2000 or 3000 μmol·L–1 each or with combinations (1000 + 1000, 2000 + 2000 or 3000 + 3000 μmol·L–1) and then placed in flat trays containing autoclaved sand at 25 ± 2ºC in 16 h photoperiod at 35 µmol·m–2·s–1. After 28 days, softwood cuttings treated with IBA + NAA (3000 + 3000 μmol·L–1) had highest rooting percentage (89.3%) with 5.5 mean roots. Shoot apex and nodal explants of softwood cuttings were pretreated with 0.1% (w/v) ascorbic acid, boric acid, activated charcoal, citric acid, glutamine or polyvinylpolypyrollidone (PVP) for 24 h to remove phenolic compounds before surface disinfestation. Glutamine (Gl) and PVP were equally effective resulting in 60% establishment of shoot apices on MS medium supplemented with 10 μmol·L–1 6-benzylaminopurine (BAP) + 5 μmol·L–1 NAA. Using shoot apices, highest (42.80) number of multiple shoots with 54.33 mm shoot length were obtained on MS + BAP (8.8 μmol·L–1) + IBA (2 μmol·L–1) after 45 days. Shoots were successfully rooted and acclimatized to greenhouse 相似文献
10.
Qiong Zhao Xingyu Liu Dehui Zeng Jinhuan Liu Yalin Hu 《Frontiers of Forestry in China》2009,4(1):85-89
In order to find out the best foliar diagnostic index of phosphorus (P) nutrition in Mongolian pine (Pinus sylvestris var. mongolica) in the southeastern Keerqin Sandy Lands, the concentrations of total nitrogen (N), inorganic P, organic P and total P in
needles of different ages and soil available P were examined. The results show that in the study area, soil available P was
rather low (0.12–0.63 mg/kg) and was significantly correlated with inorganic P (cPi) and total P (cPt) concentrations in current
year needles of Mongolian pine. The significant correlation between soil available P and needle cPt derived from the significant
correlation between cPi and cPt. Compared with cPt, cPi did reflect the level of soil P supply more accurately and more directly.
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Translated from Chinese Journal of Applied Ecology, 2008, 19(3): 494–498 [译自: 应用生态学报] 相似文献
11.
Spatial distribution characteristics of fine roots of Populus euphratica in a desert riparian forest
The soil-plant system is a very important subsystem of the soil-plant-atmosphere continuum (SPAC). The water uptake by plant
roots is an important subject in the research on water transport in this SPAC and is also the most active study direction
in the fields of ecology, hydrology and environment. The study of the spatial distribution pattern of fine roots of plants
is the basis of constructing a water absorption model of plant roots. Our study on the spatial distribution pattern of fine
roots of Populus euphratica in a desert riparian forest shows that the density distribution of its root lengths can be expressed horizontally as a parabola.
The fine roots are concentrated within the range of 0–350 cm from the tree trunk and their amount accounts for 91.9% of the
total root mass within the space of 0–500 cm. In the vertical direction, the density distribution of the fine root lengths
shows a negative exponential relation with soil depth. The fine roots are concentrated in the 0–80 cm soil layer, accounting
for 96.8% of the total root mass in the 0–140 cm soil layer.
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Translated from Chinese Journal of Ecology, 2007, 26(1): 1–4 [译自: 生态学杂志] 相似文献
12.
云斑白条天牛在黄河三角洲地区严重危害白蜡树,本研究应用聚集指标法、Taylor幂法则、Iwao m*-m回归分析法,对危害白蜡云斑白条天牛种群卵、幼虫、成虫的空间分布型和抽样技术进行了研究。结果表明:危害白蜡云斑白条天牛种群的卵、幼虫、成虫均呈聚集分布,其聚集性随密度的增加而增大。运用Iwao m*-m回归中的两个参数α和β值,建立了在不同精度下以刻槽、排粪孔和羽化孔为防治指标时的理论抽样数公式及序贯抽样数公式,计算出了抽样调查时的理论抽样数据表及序贯抽样数据表,在生产实践中可根据实际需要查询表中数据确定调查样本数。 相似文献
13.
沙棘木蠹蛾幼虫空间分布型及抽样技术 总被引:1,自引:0,他引:1
应用聚集度指标判断分析沙棘木蠹蛾幼虫空间分布型,结果为:沙棘木蠹蛾幼虫空间分布型属聚集分布。以平行线、对角线、五点式、Z字型4种取样方法调查,分别计算m(平均数)、s(标准差)、CV值,并与对照地进行比较,确认为对角线和五点式的取样效果最好。 相似文献
14.
Peroxidase activity and isoenzymes of fresh wood samples of the third shoot of 12-year old trees and from the sapwood, transition
zone and heartwood of c. 60-year old stems of Scots pine (Pinus sylvestris L.) were investigated. Wood samples were ground at −30°C, extracted, and the extracts concentrated c. 20-fold for peroxidase
activity assays (guaiacol method) and for IEF-PAGE. At least 11 major isoenzymes could be found in the gels. Even the heartwood
contained some peroxidase isoenzymes. Isoenzyme patterns of the juvenile wood did not change with the season. However, juvenile
wood showed the highest peroxidase activity at the end of the growing season. Peroxidase activity decreased from the outer
sapwood towards the heartwood. Thin sections of different wood zones stained for peroxidase revealed activity in ray parenchyma
and resin canal epithelial cells. Intensive staining was localised in the bordered pits of vertical and ray tracheids, and
in the end walls of ray parenchyma cells. 相似文献
15.
Andrzej Borkowski 《Journal of Forest Research》2007,12(5):358-364
Methods of spatial distribution of fallen shoots, pruned by pine shoot beetles, and estimation of efficiency of methods based
on collection of fallen shoots and used in forecasting of the occurrence of these insects, are presented in this paper. The
fallen shoots were distributed in clusters. The distribution was statistically different from random. Relative errors in estimation
of shoot-fall density were the smallest in study transects. Early and late autumn and the following spring, after the snow
melt, are the optimum seasons for collecting fallen shoots. 相似文献
16.
The aim of the study was to investigate dynamics and pattern of natural regeneration and the influence of seedbed and light
on germination and initial seedling survival of Scots pine (Pinus sylvestris L.) during three growing seasons. Four 5-m2 plots in a natural Scots pine forest in central Spain were randomly established at the beginning of the regeneration process.
Germination and seedling survival were recorded in 100 regeneration sampling subplots (0.25 m2) per plot, while seedbed type and the relative light intensity reaching the forest floor was characterised in 1-m2 subplots. The spatial correlations between survival, light conditions and organic matter depth were analysed through cross-variograms.
Germination and survival were highly variable both within and between plots (ranging from 0 to 89%) and affected by high summer
temperatures (33–35°C) in 2003. The spatial pattern characterisation of survival by Ripley’s K function showed a dominant cluster distribution. Occurrence tended to be clumped when abundance was greater than 15 seedlings,
whereas for lower densities, seedlings were randomly distributed. Seedlings and herbs occupied the same sites where environmental
conditions were appropriate for them to live. Spatial association occurred frequently for light and organic matter depth.
Results suggested that the Scots pine seedlings in our study in central Spain preferred moderate light conditions (Global
Site Factor <0.40). Thus, if this forest is to be naturally regenerated with Scots pine, the shelterwood system (whereby some
mother trees are left to provide shelter for at least 5 years), along with mechanical disturbance of the seedbeds, would promote
seed germination, as long as a seed source is present. However, regeneration success is affected by year-to-year conditions. 相似文献
17.
Effects of drought stresses induced by polyethylene glycol (PEG) (0.0%, 10%, 15%, 20%, 25%, and 30%, with four replicates)
on germination of Mongolian pine (Pinus sylvestris var. mongolica) seeds produced in plantations (southern Keerqin sandy land) and natural forests (Hulunbeier sandy plain) were observed.
The results indicated that the seeds from both provenances did not germinate when PEG concentration was more than 25%. The
time of initial germination and that of its completion of stressed seeds from both provenances were delayed when compared
with the unstressed seeds. The germination capacity and germination rate of natural seeds were significantly higher than those
of plantation seeds for all treatment levels (P < 0.05). The mean growth rates of radicle and hypocotyl from natural seeds were significantly higher than those from plantation
seeds at all treatment levels below 20% PEG treatment (P < 0.05). The ratios of radicle to hypocotyl of 20% PEG treatment were significant higher than those of the corresponding
controls for both provenances (P < 0.05). These results suggested that Mongolian pine seeds/seedlings had stronger resistance to PEG drought stresses; 10%
PGE stress did not significantly influence germination. Natural seeds exhibited more resistance to PEG stress than plantation
seeds. It was concluded that drought stress on seed germination might be one cause of obstructed natural regeneration of Mongolian
pine plantations on sandy land. It is recommended that natural seeds be used for afforestation, and light drought stress (e.g.,
10% PEG stress) may be useful in improving seed germination and the growth of radicles and hypocotyls. 相似文献
18.
Fixed quadrates were established in different stands. In continued six years, the occurring period, occurring amounts and
the relation between epidemic disease and environmental factors were investigated according to spraying laws of spores and
accounting measures of disease ranking. The occuring peak period of the disease was from the last ten days of May to the second
ten days of June. The epidemic period was from the last ten days of June to the second ten days of July and the initial decease
period was from the last ten days of July to the beginning of September. The change of the disease depended on air temperature,
relative humidity and precipitation. A multiple linear regression model was established using computer, which can predict
the disease index(Y) of 10 days later, with more than 95% reliability
(Responsible Editor: Chai Ruihai) 相似文献
19.
The spatial distribution patterns of the attack on fresh logs ofPasania edulis was studied for the oak borer,Platypus quercivorus (Murayama), and two species of Scolytid ambrosia beetles,Xylosandrus crassiusculus (Motschulsky) andXyleborus attenuatus Blanford, in 1994 and 1995. On the logs where onlyP. quercivorus attacked, the entry holes were distributed uniformly when attack intensity was low. However, the distribution pattern became
more aggregated with the increase in attack intensity. On logs where bothP. quercivorus and the two Scolytid species attacked, there was a negative association between the spatial distribution of the entry holes
ofP. quercivorus and that of scolytids. Simultaneous attack of two scolytids also increased the degree of aggregation of the entry holes ofP. quercivorus. The entry holes of scolytids were distributed in groups irrespective of the attack intensity of scolytids andP. quercivorus. These results suggest an asymmetrical interspecific relationship betweenP. quercivorus and scolytids. Concentration of the entry holes ofP. quercivorus in a small area may cause a considerable decline in the reproductive success in the galleries constructed there. 相似文献
20.
[目的]对云南松种群年龄结构和空间分布格局的变化以及不同生长阶段个体的空间分布格局及空间关联性进行了研究,从空间格局角度深入认识云南松林群落结构和分布格局及其形成的内在机制。[方法]基于云南省云龙县天池自然保护区云南松天然林的样地调查数据,基于云南松的种群径级结构,采用Ripley’s L函数点格局方法,对云南松自然种群的龄级结构、空间分布格局及其不同生长阶段空间关联性进行了系统分析。[结果]云南松自然种群径级和高度级结构完整,分布呈倒\"J\"型;云南松自然种群整体上在0 40 m的空间尺度上呈\"聚集-随机\"的分布格局;云南松自然种群个体在幼树和小树阶段,在较大的尺度上呈聚集分布,随着尺度的增加转变为随机分布,而在中树阶段完全呈聚集分布,随着龄级的递增,大树阶段的空间分布格局呈随机分布;云南松自然种群不同生长阶段个体间空间关联在所有尺度上基本都呈显著正相关。[结论]云南松自然种群结构属增长型种群;云南松自然种群不同生长阶段的个体呈现不同的分布格局,表现出强烈的空间动态特性;云南松种群各生长阶段间正向的关系,有利于种群的维持。 相似文献