首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 7 毫秒
1.
On the arable land of the Rosovka Stream alluvium in the Czech Republic, a windbreak containing native woody species, was planted within a restoration project. This study evaluates the effect of that planting of three different tree sizes, on the rate of growth. The sizes of transplants employed in this study included small (1.0–1.5 meters tall), medium-sized (2.0–2.5 meters tall) and large (with a trunk circumference of 0.1–0.12 meters). The following native tree species, from the Eurosiberian region, were used: Quercus robur L., Carpinus betulus L., Fraxinus excelsior L., Acer campestre L., Acer pseudoplatanus L., Tilia cordata Mill., and Prunus avium L. Growth rates were monitored over a five-year period. Small transplants had the highest growth; they grew approximately 0.4 meters more than transplants from the other size categories. Our results show that the selection of the size of transplant has a significant impact on development and growth. However, differences in the post-transplant responses of individual species were found.  相似文献   

2.
为了探明秸秆覆盖栽培对西瓜产量及土壤水分的影响,选用玉米秸秆在生育期设置地表全覆盖(WM)、行间覆盖(SM)和根域覆盖(RM)3个覆盖处理,以不覆盖为对照(CK),研究不同秸秆覆盖方式对旱作西瓜不同生育时期土壤总贮水量、不同深度土壤含水量及产量的影响.结果表明:秸秆地表全覆盖和根域覆盖处理显著提高了西瓜全生育期根域和行间0~120 cm的土壤含水量和贮水量,且伸蔓后期以后的土壤贮水量根域高于行间;秸秆覆盖处理对西瓜伸蔓后期至膨大前期的土壤含水量影响最大,随着西瓜的生长发育,秸秆覆盖处理提高根域土壤含水量的幅度增加,深度下延.秸秆覆盖处理提高西瓜产量主要受根域土壤水分条件改善的影响;各覆盖处理均显著提高了西瓜的产量和水分利用效率,WM、SM和RM处理的增产幅度分别为24.8%、11.5%和15.1%,水分利用效率分别提高了42.7%、24.3%和294%.以地表全覆盖13500 kg·hm-2秸秆量的处理蓄水保墒、提高西瓜产量和水分利用效率的效果最显著.  相似文献   

3.
Types of the daily course of transpiration rate were studied in two-year old seedlings ofPinus silvestris L.,Picea excelsa L.,Larix decidua L.,Tilia cordata Mill., andAlnus glu-tinosa (L.) Gaertn. The curves illustrating the daily development of transpiration rate (Figs. 3 - 8) may be grouped in two types, showing a midday maximum (one-peak curves) and a midday depression (two-peak curves). Unlike herbaceous plants, the seedlings ofPinus silvestris L. were found to show, during the night-time, lower but not negligible values for the rate of transpiration (see Figs. 3 and 8). The following times are considered most suitable in determining the rate of transpiration for both herbs and woody species during the daylight: 09.0, 12.0, 14.0, and 17.0 hours. For the forest species seedlings further times are suitable for the night-time, as follows: 23.0, 01.0, and 06.0 hours. The rate of transpiration in the seedlings of Pinus silvestris attained very low levels at 3 and between 6 and 8 a.m. and between 6 and 8 p.m. (see Figs 3 and 8).  相似文献   

4.
As Iran is one of the main origins of Prunus germplasm. In this study, ISSR markers were used for genetic diversity evaluation of 39 accessions of subgenus Cerasus belonging to six species i.e. Prunus avium L., Prunus cerasus L., Prunus mahaleb L., Prunus incana Pall., Prunus microcarpa Boiss., and Prunus brachypetala Boiss.. With 12 ISSR primers, 151 polymorphic bands were detected with polymorphism ratio range of 81.8%–100%. The lowest similarity (0.04) was found between P. avium and P. microcarpa genotypes and the mean of similarity between all genotypes was 0.28. Cluster analysis separated improved cultivars from wild accessions. Improved cherry cultivars and rootstocks were placed closer to the P. avium than the other species. The principal coordinate analysis (PCoA) supported the cluster analysis results. The wild accessions were separated according to their species and collection sites. ISSR markers are useful techniques for genetic diversity evaluation in Prunus subgenus Cerasus.  相似文献   

5.
Maize (Zea mays L.) is an important grains cereal crop. Lots of farmers using tillage and mulching practices influence the final yield, to maintain up with the growing demand for food, fuel and feed. Field experiments were conducted to investigate the effects of tillage practices (i.e. conventional tillage CT, reduced tillage RT, deep tillage DT) and wheat straw mulching (i.e. no mulch and wheat straw mulch of 4, 8 and 12 Mg ha−1, SM0, SM1, SM2 and SM3 respectively) on the growth, yield and yield components of maize and some of soil physical properties. The results showed that compared with RT, DT and CT decreased soil bulk density, as well as led to increase soil water content. Application of mulch treatments increased soil water content. DT and CT have been associated with greater plant height, yield components, grain and biomass yield than RT treatment. Plant height, yield components, grain and biomass yield as well as soil water content increased following mulching treatments. Mulching treatment of SM2 had the largest positive effects on maize yield. DT and CT that have potential to break the compacted zone in soil leading to a better soil environment and crop yield. The application of wheat straw mulch could be an efficient soil management practice for corn production in arid subtropical climate region.  相似文献   

6.
Nurse-plant effects have been used as an effective reforestation and restoration strategy, and mulching has also effectively ameliorated soil-adverse conditions. However, use of nurse plants is limited by the presence of suitable nurse species before trees are planted, and use of mulching depends on availability of appropriate materials. The effects of Lupinus elegans as a nurse plant and pine-bark mulch were tested on three conifer species: Pinus montezumae, Pinus pseudostrobus, and Abies religiosa. We tested if nurse-plant type effects occurred if the lupines and the conifers were planted simultaneously. Overall survival was 53%, and significant differences among species were found. Survival regardless of cover type was significantly higher (P < 0.01) for P. pseudostrobus 17-month-old seedlings at planting (81%), followed by P. montezumae 7-month-old seedlings at planting (71%), P. pseudostrobus 7-month-old seedlings at planting (42%) and finally A. religiosa 7-month-old seedlings at planting (17%) the differences among the treatments were significant (P < 0.01). As a soil shading agent, lupines had a significant effect (P = 0.02), because they increased survival of P. pseudostrobus and A. religiosa, the effect of mulching with pine bark was not significant. The effects of a shading agent on growth differed among species. In particular lupines reduced height and stem diameter for P. montezumae and P. pseudostrobus, between 22% and 33%, and had no effect on growth of A. religiosa. The positive effects of the simultaneous planting of L. elegans on the survival of the trees suggests that nurse-plant facilitation can be used in areas where no suitable nurse plants are already present.  相似文献   

7.
We examine the effect of mulches on the soil volumetric water content (SVWC), pH, carbon (C), total and mineral (NH4 and NO3) nitrogen (N), total and bicarbonate phosphorus (P), and on the survival and relative growth rate of three species, Ipomea wolcottiana Rose, Lonchocarpus eriocarinalis Micheli and Caesalpinia eriostachys Benth, in a degraded seasonally dry tropical forest (SDTF) area. Our study year was unusually dry, with only half of the mean annual rainfall. Sixteen plots (5 × 6 m) for each of our four treatments, mulches with alfalfa (Medicago sativa L.) straw, forest litter (SDTF litter), polyethylene and bare soil (control), were used. In each plot, 20 tree saplings were planted of each species. The SVWC was higher in plots mulched with polyethylene than in bare soil plots. The soil pH did not change with mulching, and there were no differences between treatments in the concentrations of soil organic C, total N, NO3 and total P. However, soil concentrations of NH4 were highest in plots with alfalfa straw and of bicarbonate P in plots with polyethylene. Sapling survival was higher in polyethylene mulch plots than in other mulching treatments, in the order I.␣wolcottiana > C. eriostachys > L. eriocarinalis. Sapling survival under organic mulches, alfalfa straw and forest litter were similar, and lowest in bare soil. The relative growth rate followed the order L. eriocarinalis < C. eriostachys < I. wolcotiana, and the growth rate of all species was greatest under polyethylene mulch. We conclude that a combination of polyethylene mulch with species of high growth rate is best for restoring seasonally dry tropical areas.  相似文献   

8.
The genus Crataegus is well distributed in Turkey as a wild plant, with numerous, inherently variable species and genotypes. RAPD markers were used to study 17 hawthorn genotypes belonging to Crataegus monogyna ssp. monogyna Jacq (2 genotypes), C. monogyna ssp. azarella Jacq (1), Crataegus pontica K.Koch (3), Crataegus orientalis var. orientalis Pallas Ex Bieb (3), Crataegus pseudoheterophylla Pojark (1), Crataegus aronia var. dentata Browicz (1), C. aronia var. aronia Browicz (4), and Crateagus × bornmuelleri Zabel (2). The 10 RAPD primers produced 72 polymorphic bands (88% polymorphism). A dendrogram based on Jaccard’s index included four major groups and one outgroup according to taxa. The lowest genetic variability was observed within C. aronia var. aronia genotypes. The study demonstrated that RAPD analysis is efficient for genotyping wild-grown hawthorns.  相似文献   

9.
The photosynthetic capacity of woody plants in the urban environment was evaluated from the level of reduced assimilates. Marked inhibition of carbohydrate synthesis was observed in Siberian mountain ash (Sorbus sibirica Hedl.) and small-leaved linden (Tilia cordata Mill.) during vegetation, which was negatively correlated with the total atmospheric pollution in different districts of the city. It is concluded that this index of photosynthetic capacity can be used as an indicator of overall urban air pollution, and Tilia cordata as an environmental indicator species.  相似文献   

10.
Straw mulching is an effective measure to conserve soil moisture. However, the existence of straw on the soil surface also affects soil temperature, which in turn influences crop growth, especially of winter crops. Five‐year field experiments (2000–2005) investigated the effects of straw mulching and straw mass on soil temperature, soil evaporation, crop growth and development, yield and water use efficiency (WUE) of winter wheat (Triticum aestivum L.) at Luancheng Station on the North China Plain. Soil is a moderately well‐drained loamy soil with a deep profile at the station. Two quantities of mulch were used: 3000 kg ha?1 [less mulching (LM)] and 6000 kg ha?1 [more mulching (MM)], representing half and all of the straw from the previous crop (maize). In the control (CK), the full quantity of mulch was ploughed into the top 20 cm of soil. The results showed that the existence of straw on the soil surface reduced the maximum, but increased the minimum diurnal soil temperature. When soil temperature was decreasing (from November to early February the next year), soil temperature (0–10 cm) under straw mulching was on average 0.3°C higher for LM and 0.58°C higher for MM than that without mulching (CK). During the period when soil temperature increased (from February to early April, the recovery and jointing stages of winter wheat), average daily soil temperature of 0–10 cm was 0.42°C lower for LM and 0.65°C lower for MM than that of CK. With the increase in leaf area index, the effect of mulching on soil temperature gradually disappeared. The lower soil temperature under mulch in spring delayed the development of winter wheat up to 7 days, which on average reduced the final grain yield by 5% for LM and 7% for MM compared with CK over the five seasons. Mulch reduced soil evaporation by 21% under LM and 40% under MM compared with CK, based on daily measuring of microlysimeters. However, because yield was reduced, the overall WUE was not improved by mulch.  相似文献   

11.
Tilia cordata Mill. is a valuable tree species enriching the ecological values of the coniferous‐dominated boreal forests in Europe. Following the historical decline, spreading of Tilia sp. is challenged by the elevated inbreeding and habitat fragmentation. We studied the geographical distribution of genetic diversity of Tilia cordata populations in Lithuania. We used 14 genomic microsatellite markers to genotype 543 individuals from 23 wild‐growing populations. We found that Tilia cordata retained high levels of genetic diversity (population F IS = 0–0.15, H o = 0.53–0.69, H e = 0.56–0.75). AMOVA, Bayesian clustering, and Monmonier''s barrier detection indicate weak but significant differentiation among the populations (F ST = 0.037***) into geographically interpretable clusters of (a) western Lithuania with high genetic heterogeneity but low genetic diversity, bottleneck effects, (b) relatively higher genetic diversity of Tilia cordata on rich and most soils of midland lowland, and (c) the most differentiated populations on poor soils of the coolest northeastern highland possessing the highest rare allele frequency but elevated inbreeding and bottleneck effects. Weak genetic differentiation among the Tilia cordata populations in Lithuania implies common ancestry, absence of strong adaptive gradients, and effective genetic exchange possible mediated via the riparian networks. A hypothesis on riparian networks as gene flow mediators in Tilia cordata was raised based on results of this study.  相似文献   

12.
Latent pathogenic fungi (LPFs) affect plant growth, but some of them may stably colonize plants. LPFs were isolated from healthy Houttuynia cordata rhizomes to reveal this mechanism and identified as Ilyonectria liriodendri, an unidentified fungal sp., and Penicillium citrinum. Sterile H. cordata seedlings were cultivated in sterile or non-sterile soils and inoculated with the LPFs, followed by the plants’ analysis. The in vitro antifungal activity of H. cordata rhizome crude extracts on LPF were determined. The effect of inoculation of sterile seedlings by LPFs on the concentrations of rhizome phenolics was evaluated. The rates of in vitro growth inhibition amongst LPFs were determined. The LPFs had a strong negative effect on H. cordata in sterile soil; microbiota in non-sterile soil eliminated such influence. There was an interactive inhibition among LPFs; the secondary metabolites also regulated their colonization in H. cordata rhizomes. LPFs changed the accumulation of phenolics in H. cordata. The results provide that colonization of LPFs in rhizomes was regulated by the colonizing microbiota of H. cordata, the secondary metabolites in the H. cordata rhizomes, and the mutual inhibition and competition between the different latent pathogens.  相似文献   

13.
Five species of larval parasitoids were reared fromRhagoletis pomonella (Walsh) infested fruit of hawthorn,Crataegus, collected from several locations in southwest Washington over a four year period. A braconid,Biosteres melleus (Gahan), parasitized larvae infesting fruits of a native hawthorn species,Crataegus douglasii Lindl. Another braconid,Opius downesi Gahan, emerged exclusively fromR. pomonella pupae reared from fruits of an introduced species of hawthorn,Crataegus monogyna Jacq. A pteromalid,Pteromalus sp., and two eulophids,Tetrastichus spp., attackedR. pomonella larvae infesting fruits of both hawthorn species. No parasitoids emerged from a total of 4385 pupae reared from apple. Percent parasitism ofR. pomonella was higher inC. monogyna compared toC. douglasii fruits. The highest average levels of parasitism ofR. pomonella inC. monogyna andC. douglasii fruits were 90% and 23% respectively. The kinds of parasitoids, their relative abundances and timing of parasitization on the two hawthorns was related to differences in fruit ripening patterns and its effect on the development ofR. pomonella on these two hosts. Parasitization ofR. pomonella byTetrastichus spp. is a new host record. The detection of these species andPteromalus sp. in southwest Washington are the first records of ectoparasitoids attacking this tephritid.  相似文献   

14.
为探明保护性耕作对蔗田土壤及甘蔗生长的影响,该研究设置2种耕作方式(常规耕作、粉垄耕作)与2种施肥水平(减量施肥20%、常规施肥),并于甘蔗苗期后在甘蔗行间近根部覆盖豆科秸秆,以第二年宿根蔗为研究对象,采用染色示踪法测定秸秆覆盖下蔗田土壤优先流特征,同时测定分析甘蔗株高、茎围、地下根系生物量、产量及品质等重要农艺性状。结果表明:(1)粉垄耕作方式下蔗田土壤优先流发生速度快且活跃,添加秸秆覆盖降低了土壤优先流发生程度,增加了土壤水分在10~25 cm土层的横向运移能力,在一定程度上提高了土壤蓄水能力。(2)粉垄保护性耕作在秸秆覆盖下提高了甘蔗根系生物量和产量,秸秆覆盖下粉垄免耕宿根蔗根系生物量提高了8.97%~25.54%,并且减量施肥处理中秸秆覆盖宿根蔗伸长期地下根系生物量显著高于无秸秆覆盖,秸秆覆盖下甘蔗株高提高了4.2%~13.1%; 在减量施肥处理中,粉垄耕作添加秸秆覆盖甘蔗产量提高了16.27%,并且添加秸秆覆盖较常规施肥中无秸秆覆盖,产量提高了5.95%。(3)粉垄保护性耕作利于提高甘蔗品质,对比无秸秆覆盖处理,粉垄耕作下秸秆覆盖后显著提高了甘蔗蔗汁视纯度,并且宿根蔗纤维分、蔗汁锤度、转光度和蔗糖分均有提升。综上认为,免耕秸秆覆盖可作为粉垄红壤坡耕地蔗田保护性生产调控方式。  相似文献   

15.

Background and Aims

In the UK, the flowers of fruit-bearing hedgerow plants provide a succession of pollen and nectar for flower-visiting insects for much of the year. The fruits of hedgerow plants are a source of winter food for frugivorous birds on farmland. It is unclear whether recent declines in pollinator populations are likely to threaten fruit-set and hence food supply for birds. The present study investigates the pollination biology of five common hedgerow plants: blackthorn (Prunus spinosa), hawthorn (Crataegus monogyna), dog rose (Rosa canina), bramble (Rubus fruticosus) and ivy (Hedera helix).

Methods

The requirement for insect pollination was investigated initially by excluding insects from flowers by using mesh bags and comparing immature and mature fruit-set with those of open-pollinated flowers. Those plants that showed a requirement for insect pollination were then tested to compare fruit-set under two additional pollination service scenarios: (1) reduced pollination, with insects excluded from flowers bagged for part of the flowering period, and (2) supplemental pollination, with flowers hand cross-pollinated to test for pollen limitation.

Key Results

The proportions of flowers setting fruit in blackthorn, hawthorn and ivy were significantly reduced when insects were excluded from flowers by using mesh bags, whereas fruit-set in bramble and dog rose were unaffected. Restricting the exposure of flowers to pollinators had no significant effect on fruit-set. However, blackthorn and hawthorn were found to be pollen-limited, suggesting that the pollination service was inadequate in the study area.

Conclusions

Ensuring strong populations of insect pollinators may be essential to guarantee a winter fruit supply for birds in UK hedgerows.Key words: Blackthorn, bramble, Crataegus monogyna, frugivorous birds, hawthorn, Hedera helix, hedgerows, ivy, insect pollination, Prunus spinosa, Rubus fruticosus, Rosa canina  相似文献   

16.
Multi‐species mixed plantations can be designed to meet social, economic, and environmental objectives during forest restoration. This paper reports results from an experiment in southern Sweden concerning the influence of three different fast growing nurse tree species on the cover of herbaceous vegetation and on the performance of several target tree species. After 10 years, the nurse trees had reduced the competing herbaceous vegetation but the effect was weak and it may take more than a decade to achieve effective vegetation control. The nurse tree species Betula pendula and Larix x eurolepis did improve stem form in some target tree species, but had a minor effect on survival and growth. The open conditions before crown closure of nurse trees strongly influence seedling performance and so delayed planting of target tree species may provide a means to avoid those conditions. Survival and growth differed greatly among the tree species. Besides the two nurse tree species mentioned above, high survival was found in Picea abies and Quercus robur and intermediate survival in Fagus sylvatica, Tilia cordata, and in the N‐fixing nurse tree Alnus glutinosa. Survival was low in the target tree species Fraxinus excelsior L. and Prunus avium. For restoration practitioners, our results illustrate the potential of using nurse trees for rapidly building a new forest structure and simultaneously increase productivity, which might be a cost‐effective strategy for forest restoration.  相似文献   

17.
In a field study, conducted at Lucknow ( 26.5 degrees N, 80.5 degrees E and 120 m altitude), India for two years (1996-1997 and 1997-1998), eight treatment combinations of two variables of organic mulch (paddy straw at 7 t/ha and no mulch) and four levels of fertilizer nitrogen (0, 80, 160 and 240 kg/ha) were examined to observe the effect of organic mulching on N-use efficiency and essential oil yield in a multi-harvested geranium crop. Results revealed that application of paddy straw mulch increased the herb and essential oil yields in geranium by 23% and 27%, respectively, over the unmulched control at planted crop harvest. Corresponding values at regenerated crop harvest were 18.7% and 19.2%. A significant response to N was observed with 160 kgN/ha in mulched plot over the same level of N in the unmulched plot. Using paddy straw mulch, nitrogen uptake by plants of planted and regenerated crops was increased by 33% and 28.4%, respectively, over the unmulched control. Apparent N recoveries by planted and regenerated crops were estimated to be 33.7% and 22.7% for the unmulched control, as against 40% and 29.2% with paddy straw mulch at 160 kgN/ha. The quality of essential oil of geranium in terms of its major constituents, citronellol and geraniol, was not affected by the use of organic mulching and nitrogen fertilization and these constituents were found to be of a standard acceptable in international trade.It was concluded from this study that use of an organic mulch with 160 kgN/ha proved better in terms of economising 80 kgN/ha to produce an economic yield of 96.1 kg geranium oil from two harvests under subtropical conditions of the north Indian plains. At 160 kgN/ha, paddy straw mulch application permitted the geranium crop to produce 18.4 kg/ha more oil which gave an additional return of Rs. 53,600/ha than that of unmulched control. Paddy straw mulch and nitrogen fertilization had no adverse effect on the quality of essential oil of geranium.  相似文献   

18.
Inoculation tests were carried out in the greenhouse on wild cherry (Prunus avium) and Italian alder (Alnus cordata) seedlings, to determine their susceptibility to certain Phytophthora species (P. citrophthora, P. alni, P. megasperma and P. cinnamomi) that are commonly present in the soil. Host susceptibility was evaluated in accordance with a disease index, with the lesion length after stem inoculation, and with a root system disease index. Wild cherry was found to be highly susceptible to P. citrophthora, and was also found to be susceptible to P. alni, although to a lesser extent. Italian alder was very susceptible to P. alni, but had only low susceptibility to P. citrophthora. The other Phytophthora species caused only modest symptoms. The danger to alder and wild cherry is all the greater because these trees not only share the same pathogens, but also commonly planted together in mixed stands. The results will now have to be confirmed by using a more natural inoculation method.  相似文献   

19.
Antibodies to phase related proteins in juvenile and mature Prunus avium   总被引:1,自引:1,他引:0  
In the search for biochemical and molecular markers of juvenility in trees proteins have been identified which are preferentially or differentially expressed in either the juvenile or the mature phases of Prunus avium cv. Stella. These fall into two classes: those which are phase-related and those which may be affected by root-shoot distance. N-terminal amino acid sequence data from some of these proteins were used to produce polyclonal antibodies to corresponding synthetic peptides in order to determine if they could be used as markers of phase state in woody plants. Western blot analysis was performed on proteins extracted from three sources; juvenile trees, mature trees and rooted cuttings from mature trees. The results showed that the antibodies recognised differentially-expressed proteins. In particular, one antibody to a juvenile specific protein cross-reacted with a polypeptide of approx. 28 kDa which was present in greater amounts in shoot tips of juvenile P. avium cv. Stella seedlings compared with rooted cuttings of mature plants placed in the same growth environment.  相似文献   

20.
The rehabilitation of vegetation on structurally crusted soils by triggering termite activity through mulch was studied on three soil types in northern Burkina Faso, West Africa. A split-plot design was used in a fenced environment for the experiment. Insecticide (Dieldrin) was used at a rate of 500 g a.i. (active ingredient)/ha to create nontermite and termite plots. Three mulch types consisting of straw (Pennisetum pedicellatum), woody material (Pterocarpus lucens), and a composite mulch (straw and woody material) applied at a rate of 3, 6, and 4 tons/ha, respectively, were used to trigger termite activity. The grasses and woody species on the plots were surveyed. Nontermite plots responded weakly to mulch treatments, but even in the first year vegetation established on termite + mulch plots. Termite activity resulted in the increase of plant cover, plant species number, phytomass production, and rainfall use efficiency. Infiltrated water use efficiency and plant diversity were not statistically different among treatments during the first 2 years but were in the third. Woody species established only on termite plots. The three types of mulch plots showed greater vegetation development than bare plots, which remained bare throughout the experiment. Analysis of the termite and mulch interaction indicated that mulch plots without termites did not perform better than bare plots, especially in the case of woody plant regeneration. Vegetation rehabilitation was best with composite and straw mulches with termites, followed by woody mulch with termites; it was worst on bare plots.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号