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1.
Natural regeneration was registered on 97 clear‐felled and scarified sites in northeastern Sweden ten growing seasons after planting. On each site, three fix plots were laid out at planting and the planted seedlings were mapped. Ten years later all healthy non‐planted seedlings were registered in an anulus of size 15.7 m2. Non‐planted seedlings were also observed in four 4 m2 squares on each fix‐plot to estimate the zero‐square frequency. Species were classified as Pinus sylvestris, L., Picea abies (L) Karst. and deciduous species (Betula pendulajpubescens Roth./Ehrh., Populus tremula L., Alnus incana (L) Moench.). On average, 7 133 non‐planted seedlings ha‐1 were found, of which 29% were conifers. Among the conifers, 71% were P. abies. More than 2 500 conifer non‐planted seedlings ha‐1 were found on 27% of the plots. The number of non‐planted seedlings was correlated to the presence of neighbouring seed‐producing stands within 100 m and decreased with rising altitude. Pinus sylvestris seedlings were more frequent on dry soils while the deciduous seedlings were more frequent on wet sites. In the 4 m2 squares, the zero‐square frequency was 29% if both conifers were and deciduous seedlings were considered and 63% if only conifers were considered. Mean height of the tallest seedling per species and square was 62 cm for P. sylvestris, 42 cm for P. abies and 107 cm for the deciduous seedlings. Key words: Alnus incana, Betula, broad‐leaves, deciduous, Norway spruce, Picea abies, Pinus sylvestris, Populus tremula, reforestation, Scots pine.  相似文献   

2.
Photosynthetic responses to a series of 1-min lightflecks (1,000μmol m−2 s−1) superimposed on a background with different duration (1, 5, and 10 min) and intensity (25 and 50μmol m−2 s−1) of low background photosynthetic photon flux density (PPFD) were measured in the leaves ofFagus crenata grown in a gap and understory of aFagus crenata forest in the Naeba Mountains. The two background PPFD intensities most frequently occurred in understory and gap sites respectively. The maximum net photosynthetic rate (P Nmax) and maximum stomatal conductance (g smax) were higher in the gap seedlings than in the understory seedlings. However, when the background PPFD was 25μmol m−2s−1, the net photosynthetic rate (P 25) and stomatal conductance (g s25) were almost the same between the gap and understory. When the background PPFD duration was 1-min, the net photosynthetic rate (P N ) at the end of each lightfleck increased progressively. When the background PPFD duration was 5- and 10-min, the increase inP N at the end of each lightfleck was less. This indicates that background PPFD duration is important to photosynthetic responses to lightflecks. The higher ratios ofP 25/P Nmax andg s25/g smax in the understory seedlings indicate that the understory seedlings can maintain relatively lower levels of biochemical and stomatal limitations than the gap seedlings under low light conditions. The ratios ofP N /P Nmax at the end of each lightfleck (IS) and light utilization efficiency of single lightflecks (LUE s) that showed the influence of lightflecks on carbon gain were higher in the understory seedlings than in the gap seedlings when the background PPFD was 25μmol m−2 s−1. This means that understory seedling are capable of utilizing fluctuating light more efficiently under low light conditions than the gap seedlings although the net carbon gain of single lightflecks (CG s) in the understory seedlings was not higher than that in the gap seedlings. There were no significant differences inIS andLUE s between understory seedlings at a background PPFD of 25μmol m−2 s−1 and gap seedlings at a background PPFD of 50μmol m−2 s−1. However,CG s in gap seedlings was higher than in understory seedlings. These results provide more evidence thatF. crenata acclimate to a natural light environment in respect to relative induction state at low background PPFD and can capture the fluctuating light at the same efficiency in both the gap and understory seedlings under natural light environments. This study was funded by the research project, Evaluation of Total CO2 Budget in Forest Ecosystems, coordinated by the Ministry of Agriculture, Forestry and Fisheries of Japan.  相似文献   

3.
In a randomized block factorial experiment, 1200 seedlings from four provenances, each of Pinus sylvestris, Pinus contorta and Picea abies were inoculated with conidia (2 × 104 and 1 × 106 conidia/seedling) of Gremmeniella abietina (Brunchorstia pinea), isolated from P. contorta plantations in northern Sweden. A further 600 seedlings were left as controls. The occurrence of symptoms and the extension of dead tissues on the annual shoots were recorded 13 months after inoculation. Only the higher spore dose resulted in significant infection. P. sylvestris and P. contorta seedlings were equally susceptible (53% infected), and significantly more infected than P. abies seedlings (39%). The annual shoots of P. sylvestris and P. abies were affected to 43% and 37% of their length, which was significantly more than 15% of the length of P. Contorta shoots. The frequency of affected seedlings differed between the most southern and northern provenances of P. sylvestris and P. abies, and between the northwestern and the south-eastern provenance of P. contorta Twenty-six months after inoculation, a higher proportion of P. contorta seedlings than P. sylvestris and P. abies seedlings had recovered, and a lower proportion of P. contorta than P. sylvestris and P. abies seedlings had died. This paper discusses why P. sylvestris was found to be more susceptible to G. abietina than P. contorta in this experiment, while the reverse is found in plantations in northern Sweden.  相似文献   

4.
Modern nursery methods of seedling production in different sized root trainers, were compared by raising seedlings of Pinus wallichiana involving costs incurred and benefits received. In order to provide a common basis for the comparisons, the study involved the raising of 1000 seedlings annually on a continuous basis for seven years. A relative economic analysis of raising P. wallichiana seedlings in 300, 150 and 100 cm3 root trainers was carried out and we estimated that the root trainers of 300 cm3 capacity recorded the highest total input cost of Rs. 35571 and Rs. 40018 for 1000 seedlings produced annually at discount rates of 12% and 6%. Seedlings raised in 100 cm3 root trainers recorded the lowest total input cost of Rs. 23390 and Rs. 27737 per 1000 seedlings annually at discount rates of 12% and 6%. Hence, returns per rupee invested in raising seedlings in the 100 cm3 root trainers accounted for the maximum benefit-cost ratio (i.e., 1.56 and 1.61) at discount rates of 12% and 6%. Thus seedlings raised in 100 cm3 and 150 cm3 root trainers were found to be most cost effective when compared with seedlings grown in 300 cm3 root trainers. The results can be attributed to the larger number of cells per tray (higher growth density) in the 100 and 150 cm3 root trainers, compared to the number of seedlings in the 300 cm3 root trainers.  相似文献   

5.
[目的]在不同供Ca2+水平下对马尾松幼苗生长及生理特性进行研究,以确定适宜马尾松生长的钙浓度,为马尾松人工林培育及合理施用钙肥提供参考。[方法]以半年生马尾松幼苗为试材,采用温室内砂培,研究不同供Ca2+水平(0.0、0.4、1.0、2.0、3.0、4.0 mmol·L~(-1)(CK))对马尾松生长及生理指标的影响。[结果]不同供Ca2+水平处理5个月后,在Ca2+水平为1.0、2.0 mmol·L~(-1)时,马尾松幼苗的株高增量和地径增量较高,其中,2.0 mmol·L~(-1)Ca2+水平的株高增量和地径增量最高。马尾松幼苗对Ca2+水平适应能力强弱顺序为2.01.00.43.00.04.0 mmol·L~(-1)(CK)。在不同生长期内,随着供Ca2+水平的增加,马尾松针叶中ROS(O2-产生速率、H2O2浓度)、MDA含量、抗氧化酶(SOD、POD、CAT和APX)活性、抗氧化物质(GSH、As A)含量、脯氨酸含量均先降低后增加,最小值均在1.0 mmol·L~(-1)或2.0 mmol·L~(-1)处理中;类胡萝卜素含量先增加后降低,其最高值均在2.0 mmol·L~(-1)处理中。马尾松幼苗的株高增量和地径增量与类胡萝卜素含量关系不明显,而与其他生理指标均呈显著负相关。[结论]马尾松幼苗适宜在1.0 2.0 mmol·L~(-1)Ca2+水平的环境中生长。在马尾松林地中,应对土壤有效钙含量进行测定,并结合植株的生长和生理特征进行综合评价后,科学合理施肥以提高生产力。  相似文献   

6.
Three different LED lamps with continuous spectra were compared against commonly used fluorescent lights. The lamps were characterized by light output, energy consumption and spectral quality for plant growth. The biological effects of light quality were compared by pre-cultivating seedlings of Picea abies (L.) Karst. and Pinus sylvestris L. under each spectrum for 35 days in a growth chamber with controlled temperature, humidity and photoperiod. The seedlings were then transplanted and cultivated for one vegetation period at the nursery, then planted outdoors on a forest field trial and followed for three years. The seedlings showed similar growth performance for all spectra tested. LED lamps have several advantages to fluorescent light such as energy consumption, longer life span and adjustable light intensity. Regarding light intensity the effects on growth performance were studied for both species using the most promising LED spectra. The photosynthetically active radiation (PAR) was maintained at 50, 100, 200 and 400 μmol?m?2?s?1. Unlike energy consumption, seedling development did not display a linear relationship to light intensity. Instead, the results show an optimum light level between 100 and 200?μmol?m?2?s?1 for the shade tolerant Picea abies seedlings and a level of around 200?μmol?m?2?s?1 for the more shade intolerant Pinus sylvestris seedlings.  相似文献   

7.
孟加拉东南部土壤中的砷含量很高,不仅威胁人的健康,而且对土壤也有破坏作用。云南石梓(Gmelina arborea)在孟加拉是个快速生长的树种,也是含砷土壤中的潜力树种。研究评价了含砷试验土中丛枝菌根真菌对云南石梓(Gmelina arborea)生长的影响。播种前,四种不同浓度的砷(10mg·kg-1、25mg·kg-1、50mg·kg-1和100mg·kg-1)被加入到试验土中。记录生长参数,如,植物的根、苗鲜重、干重、冠幅径、根长和苗高、根瘤菌和孢子菌群落。菌根植株较非菌根植株生长好。与其它含砷量高的土壤中植株的生长情况相比,在含砷量为10-mg·kg-1的土壤中,菌根植株和菌根生长效果最佳,菌根植株生物量最高。随着砷浓度的增加,种苗生长,根瘤菌和孢子菌群落均明显降低p0.05)。与非菌根植株比较,菌根植株高生长增加了40%,生物量增加了2.4倍。研究表明,根瘤菌接种可以减少有害土壤中的云南石梓(Gmelina arborea)的初生长的影响。  相似文献   

8.
Efficient nursery irrigation is a key factor for the production of high-quality forestry planting stock. Conventional timer-based irrigation systems used by most forestry nurseries have some drawbacks that, if not properly managed, can lead to over-irrigation and water wastage, leaching of nutrients and contribute to increased incidences of pests and/or diseases. A practical method to accurately measure media water content and control irrigation more carefully could prevent some of these issues. To evaluate the potential use of an automated irrigation system, commercially available Decagon EC-5 dielectric soil water content sensors were laboratory-calibrated against the gravimetric method using coir/pine bark/vermiculite, coir/perlite and pine bark media to measure water content of nursery seedling containers. Using Eucalyptus dunnii seedlings raised in polystyrene seedling containers to test the irrigation system, a datalogger was programmed to control irrigation for low (0.22–0.26 m3 m?3), medium (0.26–0.32 m3 m?3) and high (0.32–0.41 m3 m?3) watering treatments. The measurements were displayed in near real-time using a web-based system, which allowed for system checking and from which data could be downloaded. The Decagon EC-5 sensors were successfully calibrated for all media (R2 > 0.97) and provided a better estimation of media water content than the manufacturer-supplied calibration equation better-suited for soils. The automated irrigation system effectively maintained the specified media water content for E. dunnii seedlings. The high watering treatment seedlings had the highest growth rates, although this treatment also had increased leaching of nutrients. By contrast, the low watering treatment seedlings showed the lowest growth rates, although these seedlings seemed to be more robust and tolerant of water stress. This study showed that the automated irrigation system, based on measurements of the media water content, can be successfully used in scheduling irrigation for Eucalyptus seedlings, leading to potential water savings.  相似文献   

9.
《Southern Forests》2013,75(3):179-185
Pendimethalin is used by some nursery managers to control weeds in Eucalyptus and Pinus seedbeds and cutting beds of Pinus. Six trials were implemented in open-rooted seedbeds to test the response of Pinus taeda to postemergence (to the crop) applications of 2.2 kg ha?1 active ingredient of pendimethalin (the formulation contained 455 g l?1). No stunting was noticed when treating seedlings with 2.2 kg ha?1 four to 10 weeks after sowing. In one study, treated seedlings were larger than those not treated. Although the 2.2 kg ha?1 rate provided good control of the prostrate weed Chamaesyce maculata, pine seedlings developed herbicide galls on the stem near the groundline. The frequency of herbicide galls at 2.2 kg ha?1 varied by study and ranged from 0 to 28%. At present, it is not known if the frequency of gall formation depends on environmental or genetic differences.  相似文献   

10.
Perlite-peat substrate (2:1 v:v) fumigated with Basamide was inoculated with vegetative inocula (a mixture of perlite and peat moistened with the MMN liquid medium) of ectomycorrhizal fungi Suillus bovinus (isolate TUZ 105) and Inocybe lacera (isolate X/14) immediately before seeding with Norway spruce (Picea abies [L.] Karst.) in a nursery bed. Suillus inoculum was applied at rates of 0.5; 1.0; 1.5 and 2.0 litres per m2, Inocybe inoculum at rates of 0.5 and 1.5 litres per m2. At the end of the first growing season, all inoculation treatments showed a significantly greater mycorrhizal infection of bareroot seedlings compared to that found in both fumigated and unfumigated controls. The ectomycorrhizal 1-year-old seedlings were transplanted into containers. At the end of the second year, ectomycorrhizal infection of the 2-year-old container-grown seedlings was considerably less than that of the 1-year-old barerooted seedlings, probably as a consequence of too high fertility and/or insufficient porosity/aeration of pure peat moss medium. There was no difference in seedling growth between inoculated and uninoculated seedlings throughout the experiment.  相似文献   

11.
Aralia clata is an important economic species in northeast China. The experiments for determung optimum seedlings density were made in the nursery of Experimental Forest Farm of Liaoning Province. Qingyuan County, in 1997. The results of 4 repeating experiments for six densities were analyzed using variance analysis by single factor. Seedling density has great effects on growth of diameter(at foot) and height. The proper seedlings density forAralia elata was determined to be 55–65 stems/m2, or 330000 390000 hm2. Thus density can insure individual seedling’s quality and the maximum productivity of seedlings. (Responsible Editor: Chai Ruihai)  相似文献   

12.
An alginate prill formulation of Gliocladium virens (GL-21) was added as a top-dressings (54 g per m2) or incorporated into medium (1.2 kg per m3) used to grow Douglas-fir seedlings in styrofoam containers. Seedlings in the top-dress treatment were similar to control seedlings; infection and colonization by naturally-occurring Fusarium was unaffected by treatment. Incorporated G. virens reduced seedling growth and increased occurrence and colonization intensity of Fusarium. In a laboratory experiment, inoculating Douglas-fir seedlings with G. virens (10% w/w) prior to inoculation with Fusarium increased survival time when compared to concurrent inoculations of fungi.University of Idaho, Idaho Forest, Wildlife and Range Experiment Station Contribution No. 742.  相似文献   

13.
Five herbicides were evaluated for their potential to reduce reliance on directed white (mineral) spirits applications and hand weeding for grass control in P. caribaea var. hondurensis nurseries. Post-emergent applications of haloxyfop-methyl, fluazifop-P, fenoxaprop-ethyl and sethoxydim were identified as being selective to P. caribaea var. hondurensis seedlings whilst providing effective grass control. Ametryn was toxic to P. caribaea var. hondurensis seedlings at 1 kg ha–1.  相似文献   

14.
Pine forests are declining because of pine wilt disease and Robinia pseudoacacia, a nitrogen-fixing species, is dominating coastal forests along the Sea of Japan. We examined the effects of R. pseudoacacia on the regeneration of a native pine species, Pinus thunbergii. Two 200 m2 plots were set up at the border of a P. thunbergii and R. pseudoacacia-dominated area in a coastal forest. We conducted monthly censuses of emergence, distribution and survival of pine seedlings in the plots from May 2003 to December 2004. Light intensity and soil properties were also measured to analyze the relationships between the survival of pine seedlings and environmental conditions using the Mantel test and the structural equation model. Pinus thunbergii seedlings emerged in spring–early summer and in late autumn. Survival of pine seedlings in the R. pseudoacacia-dominated subplots was less than half that in the pine-dominated subplots. Survival of pine seedlings emerging in May 2003 was significantly reduced by the lower light intensity and higher soil nitrogen in R. pseudoacacia-dominated subplots. The tendency was the same for seedlings emerging from April to May 2004. We concluded that R. pseudoacacia reduced the intensity of light during the growing season and increased the nitrogen content of soil, which resulted in inhibition of the natural regeneration of P. thunbergii.  相似文献   

15.
Net photosynthetic rates (NPRs) of four species seedlings,Pinus koraiensis, Pinus sylvestriformis, Fraxinus mandshurica andPhellodendron amurense, were measured at different CO2 concentrations and time respectively in Changbai Mountain during the growing season in 1999. The seedlings were cultivated in open-top chambers (OTCs), located outdoors and exposed to natural sunlight. The experimental objects were divided into four groups by tree species. CO2 concentrations in chambers were kept at 500 μL·L−1 and 700 μL·L−1 and contrast chamber and contrast field were set. The results showed that the effects of elevated CO2 on NPR of the trees strongly depended on tree species and time. NPRs ofPinus koreainsis andPinus sylvestriformis seedlings increased with the rising of CO2 concentration, while that ofPhellodendron amurense andFraxinus mandshurica increased at some time and decreased at another time. This project was supported by Chinese Academy of Sciences Responsible editor: Chai Ruihai  相似文献   

16.
[目的]为探究西伯利亚白刺盐适应机制。[方法]以1年生西伯利亚白刺水培幼苗为材料,研究不同浓度NaCl(0、200、300 mmol·L-1)胁迫24 h后根系Na~+、K~+离子流的动态变化(利用扫描离子选择微电极技术,SIET)及植株各器官中Na~+、K~+含量的静态变化(利用电感耦合等离子体光谱仪,ICP-OES)。[结果]表明:(1)短期NaCl胁迫显著提高了西伯利亚白刺根、茎、叶中Na~+含量,其中,叶中Na~+含量是根中的3倍以上;西伯利亚白刺根、茎、叶中K~+含量保持稳定或上升;(2)盐胁迫下,西伯利亚白刺根、茎、叶中K~+/Na~+呈下降趋势,其中,在200、300 mmol·L-1NaCl胁迫下,根中K~+/Na~+差异不显著;(3)离子流结果显示,NaCl胁迫显著提高了西伯利亚白刺根系Na~+的外流;对照和200 mmol·L-1NaCl胁迫下,K~+净流量分别为156、159 pmol·cm-2·s-1,差异不显著;300 mmol·L-1NaCl胁迫显著提高了K~+的内流,净流量为-370 pmol·cm-2·s-1。[结论]综合分析认为,西伯利亚白刺通过叶片对Na~+区隔,加强根系对Na~+的外排和K~+内流,进而维持植株根系K~+/Na~+的相对平衡,以此适应盐渍环境。  相似文献   

17.
NaCl胁迫下沙枣幼苗的离子代谢特性   总被引：2，自引：1，他引：2       下载免费PDF全文
[Objective]To further understand the ion metabolism characteristics of Elaeagnus angustifolia L. under NaCl stress.[Method]The seedlings of two E. angustifolia L. provenances, which were Alaer (salt tolerance provenance) and Yinchuan (salt sensitive provenance), were treated by three NaCl concentrations (0,150,300 mmol·L-1) and sampled at the 7th day and the 30th day to measure the Na+ , K+, Ca2+, and Mg2+ contents, K+/Na+ ratio and selective absorption and transportation of K+ in tissues (roots, stems and leaves). [Result]The results showed that the Na+ content in the organizations of E. angustifolia L. sharply increased with the increase of NaCl concentration. With prolonging of stress time, the Na+ content increased in roots, and decreased in stems and leaves. After seedlings of the two provenances were treated with 150 mmol·L-1 NaCl for 7 days, the Na+ content was 2.10 times and 2.23 times in leaves, respectively, compared with the control groups, and was 1.79 times and 1.57 times in root. Meanwhile, the difference between two provenances showed a expanding trend with the increase of NaCl concentration and stress time. With the increase of NaCl concentration and extension of stress time, the K+ content, Ca2+ content and K+/Na+ ratio in organizations decreased gradually. Meanwhile, the Alaer provenance seedlings accumulated more Na+ in roots and less Na+ in leaves than that of Yinchuan provenance, and the K+ content, Ca2+ content and K+/Na+ ratio decreased less in the Alaer provenance seedlings than those of Yinchuan provenance. With the increase of NaCl concentration, the Mg2+ content in leaf gradually decrease, but the Mg2+ content in root increased 22.8~64.4% after salt stress for 7 days, and Alaer provenance seedlings increased more than Yinchuan provenance. After 30 days, there was non-significant difference with the control group on the Mg2+ content of root. K+ selective absorption of E. angustifolia L. seedlings significantly increased with increasing salt concentration of the media at the 7th days, whereas not obvious at the 30th days. When the concentration of NaCl in the media increased, the change of K+ selective transportation was not significant. [Conclusion]E. angustifolia L. seedlings increase Mg2+ content and K+ selective absorption in the roots at the early stage of salt stress to adapt saline environment. The salt-tolerance E. angustifolia L. provenance can cut off more Na+ in roots and reduce Na+ content in leaves, which cause less K+, Ca2+ and Mg2+ contents loss, especially the roots and leaves, so as to ensure that all kinds of metabolisms can go well.  相似文献   

18.
容器苗作为高效的育苗措施,可以显著地提高造林成活率。相对于1年生容器苗生长较弱、造林效果差的状况,2年生容器苗可改善造林效果。因此,针对南方红豆杉、浙江楠和浙江樟3种珍贵树种2年生大规格优质容器苗的培育需求,系统研究了缓释肥加载量对其生长、根系发育、生物量积累和分配以及N、P养分积累的影响。结果表明:(1)缓释肥加载量为1.5 kg·m-3时南方红豆杉地径达到最大值,2.5 kg·m-3缓释肥加载量能有效促进浙江樟苗高增长。缓释肥加载对南方红豆杉根、叶和总生物量积累具有显著影响;(2)南方红豆杉和浙江樟总根长、根体积和根系表面积均在3.5 kg·m-3缓释肥加载量下达到最大,而2.5 kg·m-3缓释肥加载量则可满足浙江楠根体积和根表面积的增长;(3)3.5 kg·m-3缓释肥加载量有助于3个树种2年生容器苗养分库中N素的积累,但较低缓释肥加载量(1.5 kg·m-3)利于浙江楠P素养分库的构建。养分含量的提高在一定范围内可促进容器苗生长和养分库中养分的积累,而养分含量过高不仅抑制容器苗生长,还会引起养分在苗木体内的再分配。综合考虑,建议对南方红豆杉和浙江樟2年生容器苗采用1.67 g·株-1 N素和0.74 g·株-1 P素的施肥水平进行培育,而培育浙江楠2年生容器苗宜采用1.67 g·株-1 N素和0.32 g·株-1 P素施肥水平。  相似文献   

19.
Grey mould (Botrytis cinerea Pers.: Fr.) is the most common economically important fungal disease in Swedish forest nurseries. In tests in a growth room, foliage of predisposed (preinoculation incubation at 35°C for 4 days) Scots pine (Pinus sylvestris L.) seedlings was sprayed with suspensions containing Mycostop®, Binab® TF.WP or GlioMix® at concentrations of 0.5, 1 or 0.5 g l?1, respectively, and/or conidia of B. cinerea (106 spores ml?1). Binab and GlioMix reduced grey mould in needles by 94 and 92%, respectively, and were as effective as the fungicide Euparen® M 50 WG, while Mycostop reduced disease by 51%. In one trial in a forest nursery, Mycostop, Binab and GlioMix, each applied two and four times during the growing season, suppressed spontaneous B. cinerea infections in needles of first year container-grown P. sylvestris seedlings by 16–57%, and were as effective as recommended fungicidal sprays. It was concluded that biological control has potential to effectively suppress grey mould in seedlings in forest nurseries.  相似文献   

20.
Intraspecific variation in useful tree species is a requirement for any improvement program. Fruits of P. nitida were collected from seven different sources along its geographic range in Nigeria; metrical traits of seeds and resulting seedlings were assessed as well as the biomass. There were significant (p ≤ .05) differences in seed metrical traits of length, width, and weight. Seeds from J4 had the highest germination percentage of 95%, while Ore had the lowest percentage of 70. Highest mean values of 2.22 g, 3.11 cm, and 95 for weight, length, and number of seeds per pod, respectively, were obtained from Edo seeds. There were significant (p ≤ .05) differences in seedlings height, collar diameter, number of leaves, internodes, stem dry weight, root dry weight, leaf dry weight, total dry weight, and leaf area among the sources. The highest mean values of 4.33 cm (collar diameter), 2.31 cm (internodes length), were obtained from Edo collection. Other seedling traits and biomass indices were highest in J4 provenance. J4 seedlings had the highest average relative growth rate (RGR) values of 0.0450 gg?1 wk?1 while Etemi seedlings had the highest average net assimilation rate (NAR) value of 0.0063 g2 wk?1. J4 propagule had the best overall performance and is therefore recommended as a seed source for the improvement and conservation of Picralima nitida.  相似文献   

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