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1.
In the last decades, reforestation and afforestation programs are being carried out mainly with containerized seedlings. Container design determines the morphological and physiological characteristics of seedlings. However, container characteristics are often the same for plant species with very different growth strategies. The most commonly used nursery containers are relatively shallow and limit tap root growth; consequently, species relying on the early development of a long tap root to escape drought, such as those of the Quercus genus, might need to be cultivated in deep containers. The aim of this paper was to compare the morphological and physiological characteristics of Quercus suber L. seedlings cultivated in shallow containers (CCS-18, depth 18 cm) with seedlings cultivated in deep containers (CCL-30, depth 30 cm). Both container types used were made of high-density polyethylene, cylindrical in shape, open-bottomed, with a diameter of 5 cm, two kinds of vertical ribs on the inside wall showing a cultivation density of 318 seedlings/m2. At the end of nursery culture, the seedlings cultivated in the CCL-30 deep container presented a longer tap root, higher shoot and root biomass and higher Dickson Quality Index (DQI). Moreover, the CCL-30 seedlings showed a higher root growth capacity (RGC), they reached deep substrate layers faster and they presented higher root hydraulic conductance. These morpho-functional advantages improved the CCL-30 seedling water status, which was expressed by higher stomatal conductance during an imposed drought period.  相似文献   

2.
Polythene tubes are the most commonly used seedling containers and their adoption can be attributed to high water retention that enhances seedling establishment as well as the desire for low-cost readily-available containers by nursery operators. Polythene tubes have drawbacks, however, because they adversely affect seedling root growth and are an environmental hazard. This study was conducted in Meru, Eastern Kenya, to investigate whether small-scale tree nursery operators are likely to adopt biodegradable seedling containers (cellulose papers and banana sheaths). It was hypothesised that biodegradable containers are better for seedling growth and are more environmental friendly than the widely used polythene bags. The study assessed the frequency of watering and growth (height and basal diameter) of Calliandra calothyrsus seedlings produced in various biodegradable containers under three conditions with varying watering requirements, i.e. light tree shade, shade net and polythene chambers, the first being widely used by farmers. The performance of these seedlings was later monitored in the field. Seedlings produced in biodegradable containers required more frequent watering than those in polythene bags under light tree shade and shade nets but less frequent in polythene chambers. Seedlings produced in polythene tubes had higher growth rates in the nursery, but when transplanted to the field, they were overtaken by those grown in the biodegradable containers due to transplanting shock after the polythene containers were removed. Biodegradable seedling containers can therefore be adopted in areas where water is not very limiting, and evaporation rates could be reduced and water-use efficiency improved by raising seedlings in simple polythene structures.  相似文献   

3.
In Mediterranean climates, seedlings are frequently shaded in the nursery to avoid heat damage and save water. However, the impact of this shading on the seedling quality and transplanting performance of Mediterranean species is not well known. We studied the effect of nursery shading on pre-planting features and post-planting performance of two Mediterranean tree species: the shade-intolerant pioneer Pinus halepensis and the shade-tolerant late-successional Quercus ilex. We grew one-year-old seedlings of both species under 100, 40 and 5% full sunlight. Shade had a low impact on the morphology and physiology of Q. ilex seedlings. In pines, only the deep shade treatment produced low quality seedlings with poor root development. In both species, transference to high light at planting in autumn did not impose any additional stress than that caused by frosts, but initial root growth was impaired in the two shaded treatments in pine. Post-planting growth and survival of oak seedlings showed no difference between treatments. Pine seedlings grown in deep shade showed higher mortality and lower growth after planting than those grown in full sun and intermediate light treatments, while intermediate light only reduced growth. For the nursery culture of Q. ilex seedlings, we advise using low light levels during summer to save water without impairing field performance. In P. halepensis, seedlings should be cultured under full sunlight conditions to maximize post-planting growth, but they can be cultured under intermediate light without impairing survival.  相似文献   

4.
The growth and development of Pinus pinea seedlings grown in different containers was followed through one growing season in the nursery and 3 years following outplanting in the field. The variables studied in the nursery were height, diameter, biomass of shoots and roots, nutrient uptake and root density. The measured field variables, height and diameter increment and survival, were correlated with the nursery variables. Container volume had the greatest influence on plant morphology. Containers with larger rooting volume had seedlings with larger height and diameter, greater nutrient content, and better field performance. Growing density was correlated with seedling morphology and nutrient concentration in the nursery. Among the variables that influenced container volume, the diameter of the container was the most important, while the depth of the container had a minor influence on seedling morphology.The best indicator of seedling development in the nursery was the ratio of container depth to container diameter, and the optimum ratio was 4. All containers produced seedlings with some root spiralling, including those containers with ribs. There was no relationship between either the number of spiralling roots or the angle of spiralling and container characteristics. Furthermore, root spiralling did not influence seedling performance following outplanting. Root density (root biomass/cm3) was inversely correlated with container volume but there was no correlation with either depth or growing density. The largest plants were produced with container volumes of 300–400 cm3, depth/diameter ratios of 4, and growing densities of 200–300 seedlings/m2. These growing conditions will result in larger Pinus pinea seedlings coming out of the nursery, which will increase growth following outplanting.  相似文献   

5.
The tree species Alnus acuminata and Morella pubescens, native to South America, are candidates for soil quality improvement and afforestation of degraded areas and may serve as nurse trees for later inter-planting of other trees, including native crop trees. Both species not only form symbioses with arbuscular mycorrhizal fungi (AMF) and ectomycorrhizal fungi (EMF), but also with N2-fixing actinobacteria. Because tree seedlings inoculated with appropriate mycorrhizal fungi in the nursery resist transplanting stress better than non-mycorrhizal seedlings, we evaluated for A. acuminata and M. pubescens the potential of inoculation with mycorrhizal fungi for obtaining robust tree seedlings. For the first time, a laboratory-produced mixed AMF inoculum was tested in comparison with native soil from stands of both tree species, which contains AMF and EMF. Seedlings of both tree species reacted positively to both types of inocula and showed an increase in height, root collar diameter and above- and belowground biomass production, although mycorrhizal root colonization was rather low in M. pubescens. After 6 months, biomass was significantly higher for all mycorrhizal treatments when compared to control treatments, whereas aboveground biomass was approximately doubled for most treatments. To test whether mycorrhiza formation positively influences plant performance under reduced water supply the experiment was conducted under two irrigation regimes. There was no strong response to different levels of watering. Overall, application of native soil inoculum improved growth most. It contained sufficient AMF propagules but potentially also other soil microorganisms that synergistically enhance plant growth performance. However, the AMF inoculum pot-produced under controlled conditions was an efficient alternative for better management of A. acuminata and M. pubescens in the nursery, which in the future may be combined with defined EMF and Frankia inocula for improved management practices.  相似文献   

6.
In developing countries seedlings are often produced in small-scale nurseries as a means to raise tree planting materials and, provided they are of high quality, these can form the basis for successful forest plantation initiatives. This study uses morphological characteristics to assess the quality of seedlings of three tree species (Persea americana, Cola acuminata and Dacryodes edulis) in the Western Highlands of Cameroon. The growth characteristics and quality indicators of seedlings produced in two nursery categories were compared—three nurseries collaborating with the tree domestication program implemented by the World Agroforestry Centre (Category 1) and three nurseries collaborating with government and non-governmental projects (Category 2). Seedlings produced in nurseries in the first nursery category were found to be uniform in terms of growth characteristics and quality indicators. In the second category, there were relatively higher seedling proportions having measured parameters out of threshold standards for root to shoot ratio and for sturdiness quotient. Significant differences between nursery categories (at α = 0.05) were detected in root collar diameter of C. acuminata and D. edulis and in shoot dry weight of D. edulis. These differences could be attributed to better nursery management as a results of training and technical backstopping received by nursery operators in Category 1. The level of experience of nursery operators in both categories was found to be insufficient and greater exposure to skills and knowledge could enhance the production of high quality seedlings.  相似文献   

7.
Few pine species develop a seedling grass stage; this growth phase, characterized by strong, carrot-like taproots and a stem-less nature, poses unique challenges during nursery production. Fertilization levels beyond optimum could result in excessive diameter growth that reduces seedling quality as measured by the root bound index (RBI). We grew longleaf pine (Pinus palustris), a grass stage species, in containers of four different volumes (60–336 ml) either coated with copper oxychloride or left untreated and fertilized at low, medium, or high levels of nitrogen (N). In general, N concentration of tissues rose as N rate increased, with larger changes in concentration occurring between low and medium levels than between medium and high levels. N rate influenced root tissue N concentration less than it did stems and needles. Subtle needle color differences caused by N rate were significant, suggesting its potential utility during nursery production. As expected, seedlings grew larger as container volume increased and as N rate increased. Copper treatment, which we posited could influence the RBI, tended to increase root-collar diameter and tap root biomass and decrease total root volume. Chlorophyll abundance was affected more by N rate than by container volume or copper treatment, but photosynthesis was affected more by copper treatment than N rate or container size. Although RBI was 25 % greater for seedlings grown in small containers with high N rates than those grown in large containers with low N rates, RBI ranged only from 11 to 15 %, well below the critical 27 % threshold.  相似文献   

8.
《林业研究》2020,31(4)
Seedling quality is important for subtropical tree species endangered by the degradation of natural habitats in southern China.At present,the cultural regime for raising these seedlings involving fertilizer levels and size of container is not clear.In this study,seedlings of three endangered species,red-seed tree(Ormosia hosiei),Zhejiang phoebe(Phoebe chekian gensis),and Zhejiang camphor(Cinnamomum japonicum) were evaluated along with red-bark oak(Cyclobalanopsis gilva) as a reference,a species which is not endangered.Seedlings were raised in 2.8,3.6,5.1,and 6.3 L containers and fertilizer applied at 1.0,2.0,3.0 and 4.0 kg m-3.Seedling height and leaf biomass increased in response to higher fertilizer levels while larger containers resulted in greater stem and root biomass.Root biomass of endangered species seedlings did not respond to neither treatments.Zhejiang phoebe seedlings responded to nitrogen and phosphorus uptake but red-seed tree seedlings were unaffected by any nutrient levels.Red-bark oak seedlings had high nitrogen-use efficiency.Based on the results,it is recommended using at least 5.1 L containers to culture Zhejiang phoebe and Zhejiang camphor seedlings with fertilizer at 3.0 kg m~(-3).Red-bark oak and red-seed tree seedlings should be cultured with 2.0 kg m~(-3) in smaller containers.  相似文献   

9.
Rapid early growth of tree seedlings is critical to the success of plantation establishment. We investigated the effects of seedling size (small and large) and container types (small [Lannen 121], medium [Lannen 81] and large [Forestry Tube]) in the nursery and the effects of mammal browsing after planting on growth of Eucalyptus globulus in Tasmania’s Southern Forests. After planting, seedlings were either exposed to browsing or protected from browsing by wire-mesh cages until age 6 months. Low browsing pressure resulted in around 20% and 5–10% of foliage being browsed in the large and small size categories, respectively, between 1 and 3 months after planting the uncaged treatment. 6 months after planting, height growth increment was lower, and 4 years after planting, mortality was higher in uncaged large than caged large seedling treatments. Six and twelve months after planting, seedlings raised in Forestry Tube containers had significantly greater height increment and root collar diameter relative to other treatments. By 4 years after planting, trees of the small seedling treatment had significantly greater diameter than those of the large seedling treatment, but there was no effect of container type treatment. Four years after planting there was no effect on diameter growth by browsing of <30% of foliage up to 3 months after planting, although there was greater incidence of double leaders in trees that had been browsed as seedlings. Small seedlings produced more growth 4 years after planting than large seedlings of E. globulus.  相似文献   

10.
Abstract

This study compared the effects of container type on early root system morphology of jack pine (Pinus banksiana Lamb.) seedlings to determine impacts of container type on root characteristics that may be important for tree stability. Seedlings were grown for one season in Multipots®, Ventblocks®, Copperblocks®, Starpots® and Jiffy® pellets, and for a second season in sand culture in pots. After the first growing season, roots that had grown between Jiffy plugs were cut using a knife, either “early”, in September, or “late”, in November. Seedlings produced in non-pruning containers, Multipots and Ventblocks, had more vertical structural roots, less even root distribution and high shoot:root mass after a second season. Seedlings grown in pruning containers, Copperblocks, Starpots and Jiffy pellets, had more horizontal structural roots and more evenly distributed roots. Jiffy seedlings had high shoot:root mass after pruning, but ratios decreased to low levels similar to Starpots and Copperblocks after a second season in pots. Early pruning of Jiffy seedlings removed less root mass than late pruning, but total live root mass of early and late pruned seedlings was similar after the potting trial. Pruning containers thus produced structural root forms with more desirable characteristics for tree stability. These characteristics were evident after the first season and persisted after the second season in the potting trial.  相似文献   

11.
Most tree species in tropical mountain rain forests are naturally associated with arbuscular mycorrhizal fungi. Previous studies in southern Ecuador of 115 tree species revealed that only three species were not associated with arbuscular mycorrhizal fungi. Seedlings of tropical tree species raised in the nursery may need to be associated with arbuscular mycorrhizal fungi to survive transplantation shock in higher numbers. Methods for establishing plantations with native tree species are not yet established for Ecuador. Thus, we investigated the feasibility of using mycorrhizal roots of seedlings of Inga acreana, Tabebuia chrysantha, Cedrela montana and Heliocarpus americanus that had trapped mycorrhizal fungi from forest humus in the nursery to inoculate C. montana and H. americanus with native arbuscular mycorrhizal fungi. Inoculation with either a mixture of mycorrhizal roots from the four species or only with mycorrhizal roots from the same tree species were compared with effects of moderate fertilization. Assessment of plant growth and mycorrhizal status of 6-months-old Cedrela montana and Heliocarpus americanus revealed an improvement in growth and diverse associated fungi through mycorrhizal root inoculation in comparison with moderate fertilization. Moderate fertilization did not suppress mycorrhization.  相似文献   

12.
One of the main constraints of reforestation in the Mediterranean region is low summer water availability during the first years after out planting. Plant water availability depends on the precipitation regime, but also on the physical properties of the soil. Higher survival rates result when seedlings are soil acclimated. Our main goal was to describe the morpho-physiological responses of 6-, 10- and 18-month-old Quercus coccifera seedlings growing in a natural soil (terra rossa) or a standard nursery growing medium, and to assess in the nursery if seedlings growing in natural soil were more resistant to deficit irrigation. The high growth rate achieved after 10?C18 months by terra rossa-grown seedlings in contrast with those grown in the nursery substrate suggests that the former were acclimated to the soil. Higher photosynthetic rate (A), transpiration (E) and stomatal conductance (gs) were observed in terra rossa seedlings, mainly during the first months. The higher carbon availability may account for the higher root nitrogen concentration in terra rossa-grown seedlings, which could favor their later field growth. Low-watered seedlings showed a certain degree of hardening, since after 18 months, they showed higher A, E, gs and lower photoinhibition than well-watered seedlings, likely attributable to the sharp leaf-to-root biomass ratio reduction. Carbon isotope discrimination (??) values were similar to those of well-watered plants and indicated a non-stomatal component as the main factor controlling photosynthesis in these leaves. Eighteen-month-old low irrigated seedlings had the highest mortality. Overall, results suggest that nursery terra rossa-acclimated Q. coccifera seedlings with improved physiological status and hydraulic soil-root continuity would have a higher survival rate in the field.  相似文献   

13.
Larch tree species (Larix Mill.) are both ecologically and commercially valuable in their native range and are the focus of many restoration, afforestation, and commercial reforestation efforts in the boreal forests of the northern hemisphere. Land use change, shifting climate, and poor natural regeneration are making it increasingly difficult to establish the species; therefore, artificial regeneration is critical to ensure this timber species maintains its productive role on the landscape. New stocktypes are continually being developed to aid target seedlings for difficult sites, and critical, non-confounding evaluations of them are needed for target seedling development. This research evaluates the effect of container parameters on potential target seedlings. It examines tolerance thresholds of western larch (Larix occidentalis Nutt.) with respect to moisture and temperature status in the rhizosphere during early establishment. A suite of morphological measurements was used to assess seedling quality and relative performance following transplant. Modifying a commercially available container developed four distinct stocktypes of 111, 143, 175 and 207 ml that were paired with a volume-dependent nutrient regime at two culturing densities. Seedling phenotype was affected to a greater extent by container density than by container volume. Despite changes to container volume, root:shoot were found to be similar, indicating benefits of a tailored nutrient regime during nursery culture. Simulated field trials revealed that a low density growing arrangement improved post-transplant seedling growth, specifically root growth. Also, the 207 ml container facilitated greater growth in dry soil conditions compared to smaller containers. Lower (10 °C) rhizosphere temperature hindered root growth; however, seedling survival was 100 %, warranting the testing of earlier outplanting windows for this species. This evaluation of stocktype performance contributes to a greater body of work with this species and its congeners, which will ultimately benefit reforestation and afforestation efforts alike.  相似文献   

14.
Commercially produced vegetative inocula of Laccaria laccata and Hebeloma crustuliniforme successfully formed ectomycorrhizae with Douglas-fir transplanted container (plug+1) seedlings. After 4.5 months in containers, 83% and 90%, respectively, of short roots were mycorrhizal. L. laccata- or H. crustuliniforme-inoculated seedlings had significantly more mycorrhizal and total short roots than Pisolithus tinctorius-inoculated (4% mycorrhizal root tips) or uninoculated control seedlings. No significant differences were detected in seedling growth at the end of the container phase.After transplantation and growth in nursery beds for 17 months, mean new short root colonization of all seedlings was 80%. H. crustuliniforme persisted as a dominant mycorrhizal fungus on seedlings initially inoculated with this fungus. L. laccata-inoculated seedlings had 40% of their short roots colonized by L. laccata and another 40% by native fungi Rhizopogon and Thelephora spp. All mycorrhizae of control seedlings and those inoculated with P. tinctorius were formed by fungi native to the nusery beds. A significant fungal treatment effect was detected for shoot height only. Control seedlings were significantly taller than L. laccata-inoculated seedlings after transplanting.This article is part of senior author's thesis in partial fulfillment of the Ph.D. degree in the Department of Forest Science at Oregon State University, Corvallis.  相似文献   

15.
It has become apparent that some interventions are required to aid the regeneration of woody species in the Sudanian savanna. Direct seeding has been ineffective, thus planting high quality seedlings may be a viable alternative. In this study, we examined the stock quality of two valuable Sudanian savanna species, Acacia macrostachya and Pterocarpus erinaceus. Different nursery production periods were tested as well as the species’ field performance under well-watered and stressed conditions. The results showed that older seedlings (9-month) were morphologically distinct from younger ones (3-month), particularly in the case of P. erinaceus. Eighteen months after planting out, survival and growth of seedlings were not affected by initial seedling size; this was the result of the high root to shoot ratio of seedlings in all age groups at the time of planting. Seedling mortality as high as 30% was observed and attributed to both drought stress and other factors such as herbivory. Regression analyses revealed that initial shoot height was a poor predictor of field performance for both species, but initial root collar diameter accounted for 25% of the variation in diameter of P. erinaceus in the field. We conclude that initial seedling size does not affect survival and growth in the field provided that all sizes of seedling have a high root to shoot ratio at the time of planting. The prediction of field performance could be improved by developing a model that incorporates a wide range of root collar diameter.  相似文献   

16.
容器苗培育技术研究综述   总被引:2,自引:0,他引:2  
通过收集、整理国内外对容器育苗的研究进展,从容器苗的育苗容器、育苗基质、培育技术等方面综述了国内外有关苗木容器育苗研究现状。育苗容器主要从容器的种类、容器的形状及规格等方面进行评述。育苗基质主要从不同基质配比对苗木质量的影响进行评述。容器苗培育技术主要从育苗方法、断根技术、炼苗、肥力管理、化学调控技术、光周期控制对苗木质量的影响等方面进行评述。  相似文献   

17.
苗木容器育苗技术是利用容器装上营养土进行培育苗木的技术,采用这种技术培育的苗木叫容器苗。容器育苗具有节约种子,可以大量培育,不受造林季节的影响限制以及造林成活率高等特点,但是这种方法成本高,技术比较复杂,通常情况下用于裸根造林不易成活的树种。  相似文献   

18.
Selection of quality seedlings in nursery is important for raising fast-growing trees for production of fuelwood and other products. In order to identify the morphophysiological variables that can be used in nursery for selection purpose, a study on growth, drymatter production, and rate of photosynthesis was undertaken with seedlings of four tree species, viz, Acacia nilotica, Albizzia lebbeck, Dalbergia sissoo and Eucalyptus camaldulensis. The species varied significantly in growth, drymatter production and photosynthetic rate in nursery. E. camaldulensis was the fastest in growth and A. nilotica had maximum number of leaves. Total drymatter production was maximum in D. sissoo followed by A. lebbeck. The rate of photosynthesis was maximum in D. sissoo followed by A. nilotica and lowest in A. lebbeck. Among the various seedling attributes, height, number of leaves per plant, rootweight and photosynthetic rate exhibited significant correlations with seedling drymatter. Seedling diameter showed weak positive correlations with drymatter of both seedlings as well as two-year old field trees. However, number of leaves per plant, rootweight, shootweight and leafweight showed significant correlations with two-year field tree drymatter, the strongest correlation (r = 0.96, P = 0.001) was found between number of leaves per plant and field tree drymatter. Although plant height and leaf photosynthetic rate showed a positive correlation with two-year field growth, the relationship was statistically non-significant. The study reveals that maximum value for leaf number and dryweight of seedling components such as root, shoot and leaf can be used as criteria for selecting nursery stocks for field planting in semiarid conditions.This revised version was published online in November 2005 with corrections to the Cover Date.  相似文献   

19.
Fungi were isolated from the roots and growth substrate of bare‐rooted and containerized Pinus sylvestris and Picea abies nursery seedlings displaying a root dieback. Isolations were also made from visually healthy seedlings. The potential pathogenicity of all isolated species was determined in laboratory trials.

Cylindrocarpon spp., Fusarium spp. and Trichoderma viride were frequently isolated. The isolation frequency of a uninucleate Rhizoctonia‐like fungus, Pythium spp. and Phytophthora imdulatum from diseased containerized seedlings and their pathogenicity in tests suggest that these fungi are likely involved in the root dieback disease in containers. The pathogenic Rhizoctonia‐like fungus in addition to Pythium spp. was also isolated from bare‐rooted seedlings. In greenhouse tests Pythium spp. were more pathogenic to 4‐week‐old Scots pine seedlings grown before transplantation in unsterile substrate than to those seedlings grown axenically in agar. External factors are considered to have some role in the expression of disease.  相似文献   

20.
Five exotic tree species (Acacia angustissima (Mil.) Kuntze, A. mangium Wild, Gliricidia sepium (Jacq.) Alp., Leucaena hybrid (L×L), and Leucaena leucocephala (Lam.) de Wit) were investigated to determine whether parameters of nursery seedling stock quality could be used to predict their field performance in a plantation irrigated with treated waste-water to produce fodder and wood. Plants were grown in the nursery in two contrasting rooting substrates (ordinary nursery soil and sand), predicted to have different effects on resource allocation. Three categories of morphological indicators were measured, i.e., plant dimensions (height, diameter, root length), plant weights (shoot, root and whole plant weights) and indices (sturdiness quotient ‘SQ’, shoot:root dry weight ratio ‘SRR’ and Dickson’s quality index ‘DQI’). In the nursery, all species performed better in the ordinary nursery soil for all growth parameters except root length. Thus ordinary nursery substrate appeared superior to sand in terms of plant quality. However, a follow up at plantation phase revealed that only some morphological attributes or ratios were suitable to predict field performance for the five tested species in irrigated plantation. In addition, the effect of the substrate observed at the nursery stage had disappeared 12 months after out planting due to the availability of water and nutrients provided by the treated waste water used for the irrigation. The results showed that root collar diameter and DQI appeared to be the most appropriate indicators to predict the outplanting performance of the five tested species in a short-rotation irrigated plantation in semi-arid Burkina Faso. The former measure is simpler and non-destructive.  相似文献   

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