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1.
Biochemical changes associated with flowering in Bambusa arundinacea Linn and Bambusa nutans Wall.ex Munro were analyzed.Gregarious flowering was initiated in natural areas and plantations of B.arundinacea in late 2014 and reached full bloom in early 2015,whereas sporadic flowering recorded during 2014–2015 in vegetatively propagated plants of B.nutans.Leaf and nodal shoot samples from flowering culms/shoots and nonflowering culms/shoots were collected in February 2015 at the initiation of fruit filling,then analyzed and compared for soluble sugars,phenols and peroxidase activity.In both species sugars were higher in leaves of flowering culms/shoots and lower in nodal shoots of flowering culms/shoots compared to the nonflowering.Phenols were lower in leaves and nodal shoots of flowering B.arundinacea,but higher in leaves and decreases in nodal shoots of B.nutans.Peroxidase activity increases in leaves and nodal shoots of B.arundinacea after flowering but increases in nodal shoots and decreases in leaves of B.nutans.  相似文献   

2.
It is critical to understand how forests regenerate after the exclusion of human induced disturbances because the regenerating species drive the renewal of resources and ecosystems,which in turn support human beings locally and globally.This study of forest regeneration was conducted in the tropical coastal forest ecosystems of Tanzania at Uzigua Forest Reserve(24,730 ha)in the Pwani Region.We collected data from adult trees in 47 sampling plots(25×25 m)randomly established in closed forest sites(control)and in sites disturbed by farming and livestock grazing.Sapling and seedling data were collected and analyzed in 2×2 m nested subplots.Plots in the closed forest had higher mean basal area and volume for adult trees than those in sites disturbed by farming and livestock grazing.Plots in sites disturbed by farming had the highest Shannon–Wiener index for seedlings and saplings,followed by closed forest and livestock grazed sites.Closed plots and farmed plots had higher Simpson’s index for seedlings and saplings than in grazed sites.Plots in farmed and livestock-grazed sites had a higher Simpson index for adult trees than in closed sites.Equitability of seedlings and saplings was highest in closed forest sites,followed by farmed and livestock grazed sites.Plots disturbed by farming had higher equitability for adult trees than in livestock-grazed and closed sites.Moreover,plots disturbed by farming and grazing had a higher importance value index for seedlings than in closed sites.Plots in closed forests had higher sapling importance values than in farmed and grazed sites.Again,plots in closed forest had a higher importance value for adult trees than in farmed and grazed sites.The differences in tree species subcategories of regeneration across land-use indicates that farming and livestock grazing disturbances create heterogeneous microhabitats,which positively or negatively affects regeneration capacity of species after exclusion.  相似文献   

3.
Continuous increases in anthropogenic nitrogen(N) deposition are likely to change soil microbial properties, and ultimately to affect soil carbon(C) storage.Temperate plantation forests play key roles in C sequestration, yet mechanisms underlying the influences of N deposition on soil organic matter accumulation are poorly understood. This study assessed the effect of N addition on soil microbial properties and soil organic matter distribution in a larch(Larix gmelinii) plantation. In a 9-year experiment in the plantation, N was applied at100 kg N ha~(-1) a~(-1) to study the effects on soil C and N mineralization, microbial biomass, enzyme activity, and C and N in soil organic matter density fractions, and organic matter chemistry. The results showed that N addition had no influence on C and N contents in whole soil. However,soil C in different fractions responded to N addition differently. Soil C in light fractions did not change with N addition, while soil C in heavy fractions increased significantly. These results suggested that more soil C in heavy fractions was stabilized in the N-treated soils. However,microbial biomass C and N and phenol oxidase activity decreased in the N-treated soils and thus soil C increased in heavy fractions. Although N addition reduced microbial biomass and phenol oxidase activity, it had little effect on soil C mineralization, hydrolytic enzyme activities, d13 C value in soil and C–H stretch, carboxylates and amides, and C–O stretch in soil organic matter chemistry measured by Fourier transform infrared spectra. We conclude that N addition(1) altered microbial biomass and activity without affecting soil C in light fractions and(2) resulted in an increase in soil C in heavy fractions and that this increase was controlled by phenol oxidase activity and soil N availability.  相似文献   

4.
The feeding habits of the Great Spotted Woodpecker (Picoides major) were surveyed by field observations and trace checking from 2005 to 2007, in Wulate Qianqi County, Inner Mongolia Autonomous Region, China, during which the woodpecker performed fourteen types of foraging techniques. Pecking and hammering were most common in winter; gleaning and probing were most common at times of high food availability at the trunk and tree branches during the breeding season and in summer. The woodpecker gleans arthropods and insect larvae in the breeding season and summer, seeds and nuts mainly in the winter and pokes holes for sap-sucking in winter. The main diet consisted of arthropods and plant seeds. The diet was significantly different between seasons The Great Spotted Woodpecker primarily consumes defoliators and the food on tree trunks from March to October. The contribution of wood borers to the diet was higher in winter, lower in the breeding season and summer. The proportion of the food on ground was small in the breeding season and high in the Summer and winter.  相似文献   

5.
This paper deals with the chemical components and the chemical structure of lignin of Chinese fir and Poplar I-214 from plantationforest. The results revealed that the contents ofchemical component in heart wood and sapwood were almost the same except ethanol-benzene extract both in Chinese fir and in Poplar I-214, The contents of ash, holocellulose, α -cellulose, pentosan, ethanol-benzene extract and cold-water extract in Poplar I-214 were higher than that in Chinesefir, The content of lignin in Poplar I-214 was lower than that in Chinese flr. Vanillin, vanillic acid and p-hydroxybenzaldehyde were found in Chinesefir while vanillin and vanillic acid, p-hydroxybenzoic acid, syringaldehyde and syringic acid werefound in Poplar I-214 in investigation of the chemical structure of lignin by using nitrobenzene oxidization method.  相似文献   

6.
Our presentation focuses on some important issues associated with ecotourism in nature reserves in mainland China. Conducting ecotourism in certain areas in nature reserves is important for its protection. However, some problems do exist because of special conditions in our society and in the current projects of nature reserves themselves, such as water and air pollution, unplanned construction of roads and facilities, damage of core zones and buffer zones, and confused ownership of nature reserves. These problems are discussed and solutions are proposed in detail, and we emphasize the participation of local communities in order to help residents fight against poverty.  相似文献   

7.
This article dealt with the amounts and species of rhizosphere and non-rhizosphere micoorganism of the 1st and 2nd generation of Chinese fir in Shanxia and Shangcun Farms of Sub-tropical Forestry Center, CAF in Fenyi County, Jiangxi Province. It was found that the amounts and species of the actinomycetes in soil of second generation Chinese fir plantation are obviously lower than those in the first generation’s,so do the Bacillus, Azotobacter and Cellulomonas in the bacteria. But in the second generation Chinese fir plantation, the amounts of fungi and the percentage of Agrobacterium, Micrococcus and Chromobacferium in soil bacteria, Penicillium in soil fungi are much higher than those in the first one’s. The amounts of rhizosphere actinomycetes are lower than those in the non-rhizosphere’s of both 1st and 2nd generation Chinese fir plantation, yet the amounts of rhizosphere bacteria are the opposite.  相似文献   

8.
Carbon (C), nitrogen (N), and phosphorous (P) levels and their stoichiometry in plant components (leaves, branch trunks, roots) of trees in a karst forest and non-karst forest are compared. The results show that the C contents, C:N and C:P ratios of dominant species in the karst forest were lower than those in the non-karst forest, but the N and P and the N:P ratio were higher;C:N:P ratios in plant organs of trees in the karst forest were in the order of trunks>roots>branches>leaves. However, C:N:P ratio in the non-karst forest trees were trunks>branches>roots>leaves. Moreover, ratio of C:N:P in trunks was highest and lowest in leaves in both forests. In non-karst forest trees, N:P was in the order of leaves> roots>branches>trunks. There were no significant differences in the ratio of N:P in different plant components of trees in the karst forest. However, in karst and non-karst forest trees, the ratio of N:P in leaves was highest;positive correlations between N and P contents, and N and N:P ratios were observed in both karst and non-karst forests (p<0.001). Negative correlations between P and N:P ratios (p<0.05) were observed in karst forest trees, while positive correlations were observed in non-karst forest trees.  相似文献   

9.
Convenient and effective methods to determine seasonal changes in individual leaf area(LA) and leaf mass(LM) of plants are useful in research on plant physiology and forest ecology.However,practical methods for estimating LA and LM of elm(Ulmus japonica) leaves in different periods have rarely been reported.We collected sample elm leaves in June,July and September.Then,we developed allometric models relating LA,LM and leaf parameters,such as leaf length(L) and width(W) or the product of L and W(LW).Our objective was to find optimal allometric models for conveniently and effectively estimating LA and LM of elm leaves in different periods.LA and LM were significantly correlated with leaf parameters(P0.05),and allometric models with LW as an independent variable were best for estimating LA and LM in each period.A linear model was separately developed to predict LA of elm leaves in June,July and September,and it yielded high accuracies of 93,96 and 96%,respectively.Similarly,a specific allometric model for predicting LM was developed separately in three periods,and the optimal model form in both June and July was a power model,but the linear model was optimal for September.The accuracies of the allometric models in predicting LM were 88,83 and 84% for June,July and September,respectively.The error caused by ignoring seasonal variation of allometric models in predicting LA and LM in the three periods were 1–4 and 16–59%,respectively.  相似文献   

10.
Although afforestation of farmlands has been proposed as an effective method of carbon(C) sequestration, there remain uncertainties that deter us from developing a clear picture of C stocks in plantation ecosystems.This study investigated the dynamics of stand structure and plant diversity, and C and nitrogen(N) pools in trees,herbs, litter, and soil(0–100 cm depth) in black locust plantations aged 9, 17, 30, and 37 years, and in newly abandoned farmlands as pre-afforestation sites, on the Loess Plateau, China. Stand density decreased significantly, while tree diameter at breast height and height increased during stand development. The dominant species of the herb layer differed with age. Afforestation resulted in slight increases in tree C and N storage in plantations from 9 to 30 years of age, and then significantly increased from 30 to 37 years. Compared to pre-afforestation, C and N storage in soil decreased to minimum values in stands aged 17 and 9 years, respectively. The soil re-accumulated C and N during stand development, attaining equilibrium levels similar to those in pre-afforestation when stands reached about 30 years of age. Soil C and N storage in 37-year stands were 29 and 16% higher, respectively, than in pre-afforestation levels. However, C and N concentrations in the subsoil(20–40 cm) were still less than the preafforestation levels for stands of all ages(from 9 to 37 years). The relative contribution to the total ecosystem C and N pools increased in trees and decreased in soil during the observed period. Our results indicate that afforestation reduced soil C and N storage during the early stages of stand development. We conclude that the growing phase of an afforested stand over its initial 30 years is important for C and N sequestration by black locust due to the C and N storage that result from recovered soil quality and an increase in tree biomass.  相似文献   

11.
Understanding the interaction between canopy structure and the parameters of interception loss is essential in predicting the variations in partitioning rainfall and water resources as affected by changes in canopy structure and in implementing water-based management in semi arid forest plantations.In this study,seasonal variations in rainfall interception loss and canopy storage capacity as driven by canopy structure were predicted and the linkages were tested using seasonal filed measurements....  相似文献   

12.
Forest landscape ecology and its applications in China   总被引:2,自引:0,他引:2  
Landscape ecology is playing an increasingly important role in resources management and landuse planning in recent decades and attracting much attention from resource managers and scientists in China as well as in the world. Reviews of landscape ecology development in China have been well documented, whereas forest landscape ecology and its applications receive relatively fewer reviews. In this paper, we first present a brief review of the historical development and current advances of landscape ecology in China and then introduce the applications of landscape ecology to forest park designs, urban greenspace planning, ecological restoration, biodiversity conservation and forest eco-hydrology. Finally, the problems with the application of forest landscape ecology in China, such as inadequate synthesis and integration, lack of basic research on patterns and processes, basic data shortage and model usage problem are discussed on the basis of which we suggest a future direction of forest landscape ecology in China.  相似文献   

13.
A qualitative gender assessment of household-based bamboo industries was conducted in Zhuyuan and Lagadi villages in Laochang Township, Xinping County in Southwest China's Yunnan Province. Results showed that both women and men were actively involved in the production and marketing of bamboo products in the two villages. There were gender differences in bamboo-based rural industries that were closely associated with the ethnic habits, traditional norms of the rural society, the differences of educational levels that women and men achieved, and the gender blind-spots in the enforcement of laws and policies. It is evident that women were "equal" partners in the production of bamboo products, but "unequal" when the rights of access to and control over resources and personal independence are concerned. Suggestions are made to achieve a gender-balanced production system of bamboo products in rural areas of bamboo producing counties in Yunnan Province, China.  相似文献   

14.
The first issue of Chinese Forestry Science and Technology, which is the only academic Journal in English issued by Chinese Academy of Forestry (CAF), is now formally published and presented to our readers. Chinese Academy of Forestry is China's tiptop research organization in forestry, and was founded in 1912. Now it consists of 19 research institutes and centres that are distributed in major provinces and autonomous regions in China, and has a total of over  相似文献   

15.
To explore the physiological and biochemical mechanism of the occurrence of vitrified shoots of Populus suaveolens in tissue culture, the changes in water, chlorphyll, lignin, H202, phenylalanine ammonialyase (PAL), malonaldehyde (MDA), protective enzymatic systems, and some key enzymes involved in the ascorbate- glutathione cycle were comparatively studied in both normal and vitrified shoots of P suaveolens. The results show that the lower activities of peroxidase (POD), catalase (CAT), ascorbate peroxidase (APX), dehydroascorbate reductase (DHAR), glutathione reductase (GR) and PAL, and the less contents of chlorphyll, lignin, ascorbate (ASA) and reduced glutathione (GSH) as well as the lower ratios of ASA / DHA and GSH / GSSG are observed in vitrified shoots than in normal ones during the whole culture period, While in comparison with normal shoots, the higher activity of superoxide dismutase (SOD) and the more concentrations of water, H2O2, MDA, dehydroascorbate (DHA) and oxidized glutathione (GSSG) are found in vitrified shoots. Statistical analysis indicates that the enhanced activity of SOD and the decreased activities of CAT and POD as well as some enzymes involved in the ascorbate-glutathione cycle might be closely correlated to the accumulation of H202. The less regeneration of ASA and GSH and the lower capacity of the ascorbate-glutathione cycle observed in vitrified shoots might be due to a significant decrease in APX, MDAR, DHAR and GR activities and a decline in redox status of ASA and GSH. The decreases in chlorphyll content might result in a decline in photosynthesis. The lower activities of POD and PAL could result in the decrease of lignin synthesis and cell wall ligination, which might be the key factor leading to the increase in water content. It is concluded that the deficiency of detoxification capacity caused by the lower capacity of the ascorbate-glutathione pathway and the decreased activity of protective enzymatic system might lead to the large accumulation of H2O2 and the enhancement of membrane lipid peroxidation, which might be the main cause leading to the occurrence of vitrifying shoots of P.suaveolens in tissue culture.  相似文献   

16.
CO_2concentrations in different plant communities(larch, birch, lilac, and grassland) were measured during the growing season in the Heilongjiang Forest Botanical Garden to study diurnal variation, seasonal and annual dynamics and factors that impact CO_2 concentration in different spaces. CO_2 concentration in different communities in green lands had an obvious diurnal variation,chronically decreasing, and temperature influenced the lilac area and the grassland. Seasonally, CO_2 was lowest in the larch green land(344.03 ± 23.03 μmol/mol) and highest in the grassland(360.13 ± 22.43μmol/mol). The overall trend in CO_2 concentration was autumn springsummer; temperature is the main factor controlling variation in CO_2 concentrations during the growing season; the CO_2 concentration at the larch, birch, lilac, and grassland types of sites was negatively correlated with land surface temperature and air temperature, and the CO_2 concentration at the larch and birch sites was positively correlated with atmospheric pressure. Without any obvious annual change law, further study and observation are needed.  相似文献   

17.
Soil fauna can sensitively respond to alterations in soil environment induced by land-use changes.However,little is known about the impact of urban land-use changes on earthworm communities.In this study,three land-use types(i.e.,forest,nursery and abandoned lands)were chosen to identify differences in diversity,abundance and biomass of earthworm community in Kunming City.Urban land-use had a pronounced difference in species composition,evenness and diversity of earthworm communities.Forest land had the highest density,biomass and diversity of the earthworm communities.Total abundance was dominated by endogeic species in nursery land(70%)and abandoned land(80%),whereas in the forest land,the earthworm community comprised epigeic,endogeic and anecic species.Temporal changes in earthworm density and biomass were also significantly affected by land-use change.Total density and biomass of earthworms in the forest and nursery lands were highest in September,but highest in the abandoned land in October.The influence of soil physicochemical properties on the earthworm density and biomass also varied with land-use types.Soil temperature significantly affected earthworm density and biomass in the three land-use types.Soil pH was positively correlated with earthworm biomass in the forest land,but negatively associated with earthworm density in the abandoned land.Soil organic matter was positively correlated only with density and biomass of earthworms in the nursery and abandoned lands.Our results suggest that the species composition,abundance and biomass of earthworm communities can be determined by the modification of soil properties associated with urban land-use type.  相似文献   

18.
The anatomy characteristics of cell wall and lignin distribution in different anatomical regions for 12-month-old bamboo species Pseudosasa amabilis was investigated.The lignin distribution was studied by means of optical microscope and confocal laser scanning microscope and the color reaction. In addition,the distribution of lignin in different tissues(fiber,parenchyma and vessel) was investigated by visible-light microspectrophotometry coupled with the Wiesner and Maule reaction.The cell walls of different tissues were all lignified and the lignin was widely distributed in different tissues, in which there was a difference between tissues and anatomical regions in lignin content.Guaiacyl lignin and syringyl lignin unit could be found in cell wall of fiber,parenchyma and vessel through Wiesner and Maule reaction and the absorbance peak of spectrum. There was no regular variation in lignin content with different radial location of culms and different location in fiber strands.The lamellation of the fiber cell wall was generally had as alternating broad and narrow layers with alternating low and high concentration of lignin.  相似文献   

19.
The chemical compositions of the dichloromethane extracts of inner and outer barks from six Pinus species(P.elliotii,P.oocarpa,P.caribeae,P.merkusii,P.montezumae,and P.insularis) grown in Indonesia were investigated by GC and GC–MS.Generally,the amounts of extractive contents were higher in the inner bark than in the outer bark except for P.merksuii.Fatty acids,monoterpenes,sesquiterpenes,resin acids,triterpenoids,and steroids were detected and quantified.Inner and outer barks differed not only in content of these compounds but also in their composition.Fatty acids and alcohols were the major classes of lipophilic compounds in the outer bark of P.caribeae, P.insularis,and P.montezumae.Steroids and triterpenoids were the dominant compounds identified in the inner bark of P.elliotii,P.insularis,and P.merkusii.Resin acids were the most abundant group in the inner bark of P.oocarpa whereas monoterpenes and sesquiterpenes were recorded in minor quantities in both bark layers of all species.  相似文献   

20.
This paper describes the geographical distribution, utilization, cultural value and ex-situ conservation of bamboo resources in Xishuangbanna, Yunan Province, China. Sixty species of bamboo in 19 genera are recorded in Xishuangbanna. The area of natural bamboo forest is 14319 ha, accounting for 5.92% of whole area of Xishuangbanna. The abundant resource of bamboo plays an important role in the economics and culture of national minorities in Xishuangbanna. Xishuangbanna Tropic Botanic Garden, Chinese Academy of Sciences (CAS), started to introduce bamboo species in 1961 and established the ex-situ conservation reserve (8 ha) of bamboo in 1981. Up to now, 211 species in 27 genera collected from tropic and sub-tropic of China and South-east Asia have been planted in the bamboo reserve, of which 11 species have bloomed and seeded, and their seeds were cultivated in Xishuangbanna Tropical Botanic Gardens, CAS, China.  相似文献   

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