不同育苗密度对香椿苗生长和质量的影响

为了提高香椿苗木质量和造林效果,开展了香椿大田育苗密度试验.结果表明:育苗密度对苗高、地径、高径比均有显著影响(P<0.05).随着育苗密度的增大,地径逐渐减小,苗高总体减小,高径比与育苗密度没有明显的线性关系.育苗密度对苗木生物量有显著影响(P<0.05).叶、根、地上部分与单株生物量随育苗密度的减小均先增大后减小,...     

米老排不同高度级苗木形态特征的分析

通过选取50,60,70,80 cm共4种高度级的苗木,研究其形态特征的变化规律以及形态指标间相关性,旨在为米老排苗木质量评价和苗木分级造林提供参考。研究结果表明:地径、叶数和高径比随高度的增加而递增,其中地径和高径比在不同苗高等级间存在极显著差异;植株鲜质量和干质量随高度的增加而显著递增,其变化范围分别为30.32～50.52 g/株和11.26～16.91 g/株,鲜质量在不同器官中的分配规律为根<茎<叶,而干质量总体表现为根<叶<茎;植株含水率随高度级的增大呈递增趋势,各器官的含水率变化规律为根<茎<叶;在不同等级间地上与地下部分干质量比相对稳定;质量指数随高度等级的增大而增加,其值分别为1.018,1.121,1.208和1.239,但不同等级间无显著差异。苗木不同形态指标相互关联,其中苗高、地径、鲜质量和干质量以及质量指数最能反映米老排苗木生长的综合状况,宜作为苗木质量评价和分级的主要指标。     

沙区樟子松苗期干物质的研究

通过对樟子松 1年生留床苗、2年生留床切根苗、2年生移植 (未切根 )苗的干物质比较 ,结果表明 :含水量 ,2年生切根苗 <未切根 2年生苗 <1年生苗 ;生物量 ,2年生切根苗各部位干物质量 >2年生未切根苗各部位干物质量 >1年生苗各部位干物质量 ,1、2年生苗干物质主要由地上部分组成。研究结果为 :切根苗质量超过未切根苗 ,一级苗数量多于未切根苗 ;苗木在苗期积累了大量干物质 ,根系及径生长旺盛 ,樟子松在苗期非常适合沙区     

山乌桕控根容器与密度动态控制育苗效果分析

分析山乌桕绿化大苗培育中采用控根容器和密度动态调控育苗的经营效果。采用控根容器培育的山乌桕绿化大苗与普通无纺布容器苗比,苗高间差异不显著,地径显著大于普通无纺布容器苗,高径比生长协调,苗木较粗壮,主根长显著较短,而一级侧根数和根系生物量显著大于后者。控根容器培育的苗木根系多、不缠绕、无畸形,空间分布合理,苗木质量优于后者。不同密度育苗对山乌桕2 a苗龄绿化大苗根系影响不显著,但2 a苗龄摆放密度9株/m²的苗高、地径总体表现最优。因此,山乌桕2 a苗龄绿化大苗培育进程中,采用控根容器和密度动态调控可以提高苗木质量。     

樟子松苗木移植密度试验

樟子松2年生苗20 cm×20 cm、20 cm×10 cm、20 cm×7.5 cm、20 cm×5.0 cm、20 cm×4.0 cm、20 cm×3.3cm6种移植密度试验,结果表明:苗木高生长差异不明显,地径差异达到了1%的显著水准,苗木径高比,单株生物量随着移植密度的减少而增大,质量越好。一级苗百分率随密度的增大而减小,单位面积经济产值随密度的增大而上升,最大密度与最小密度的单位产值相差4倍以上。综合质量指标和经济效益2方面考虑,以20 cm×4.0 cm和20 cm×5.0 cm2种移植密度最佳。     

金沙江干热河谷3个造林树种裸根1年生苗的育苗密度研究

对川楝、新银合欢、苏门答腊金合欢3个金沙江干热河谷上段区主要造林树种不同育苗密度所培育裸根1年生苗的光生理效应、苗木的形态质量及其经济效益进行了研究。在其他育苗措施相同的情况下,苗木密度是决定其苗木质量的主要因素。随着苗木密度的增大,3树种裸根1年生苗木的总体质量随之下降,以低密度时为佳。3个树种裸根1年生苗的一级苗产量分别在其苗木密度为75株/m2、100株/m2为高,而以75株/m2时最高,虽然此时苗木的净收入不是最大值,但投入/产出比值最大。而二、三级苗木产量随其密度的增加而增加,当苗木密度为150株/m2时三级苗所占百分率接近国家标准15%的许可界限。据此3个树种的裸根1年生苗培育的苗木密度以75株/m2、100株/m2为宜,而以75株/m2为最优。     

芽苗切根移植对南酸枣苗木及造林当年生长的影响

在贵州三都进行了芽苗切根移植育苗对南酸枣1年生苗木及造林当年生长效应的研究,结果表明:1)芽苗切根移植育苗能提高苗木单株和群体质量,与常规育苗相比,芽苗切根移植育苗对苗木径生长量的提高、长5cm的侧根数量的增加及地径标准差的降低达极显著水平,对苗木高生长的提高和对高径比值、苗高标准差的降低达显著水平;2)芽苗切根移植苗造林优于常规苗造林,当年生树高、胸径生长差异达极显著水平;3)芽苗切根移植苗的高径生长节律与常规育苗一致,但各个时期的苗木高、径生长速度有差异,主要表现为缓慢生长期比常规育苗慢,快速生长期又比常规育苗快,径生长尤其突出。     

切根和生长调节剂对滇润楠苗木质量的影响

为了提高滇润楠苗木质量和造林成活率,开展不同切根强度和不同浓度植物生长调节剂(ABT)浸泡处理对滇润楠苗木质量影响的试验。结果表明:对滇润楠进行春季切根处理能有效提高苗木质量。切除主根长度的1/2能显著提高苗木Ⅰ级侧根数和地上部分鲜质量,其苗高、地径、地上部分鲜质量和全株干质量均显著大于对照。ABT处理能使苗木主根和侧根生长加快,苗木生物量与对照差异显著,特别是苗高、地上部分鲜质量及全株干质量与对照差异达极显著。     

不同断根方式对美国山核桃苗木生长的影响

对美国山核桃1年生实生苗采用切根、移栽两种断根方式,研究不同断根方式对美国山核桃实生苗生长的影响。结果表明:切根处理能促进苗木地上部分和地下部分快速生长,移栽处理能促进地下部分增粗生长,对地径生长无显著影响。移栽处理能显著促进苗木地下侧根增长、增粗,以及鲜质量增加,切根处理能显著促进苗木须根数量和鲜质量增加。对于提高苗木质量和促进美国山核桃产业发展提供参考。     

杉木扦插育苗密度的研究

研究了不同扦插密度下苗木的生长性状，质量，产量和生产成本。结果表明：不同扦插密度下，苗木的基径，高径比差异达显著或极显著水平。随着扦插密度的增加，苗木基径下降，高径比增大，质量下降，整齐度更差，Ⅰ级苗比率和成苗率均下降，苗高和分枝数也呈下降趋势。     

Sowing methods and mulch affect 1+0 northern red oak seedling quality

The effects of sowing depth, seedling density and mulches on northern red oak seedling survival and growth were evaluated in Wilson State Forest Nursery in southwest Wisconsin, USA. Sowing depths between 2.2 and 6.3 cm, combined with sowing densities of 75 and 150 acorns · m^-2, made up five sowing method plots. Mulch treatments of ground corncobs aged 1 year, hardwood sawdust aged 2 years, and no mulch made up 3 subplot treatments. Treatments resulted in a range of densities from 18 to 148 seedlings · m^-2. Mulch delayed emergence and increased seedling survival. Increasing sowing depth also delayed emergence. Corncob mulch increased root collar diameter; however, hardwood sawdust, aged for 2 years, decreased both root collar diameter and the number of permanent first-order lateral roots. Increasing sowing depth decreased root dry mass but increased shoot dry mass. Increasing density from 18 to 148 seedlings · m^-2decreased root dry mass in this study.     

Spacing of silver birch seedlings grown in containers of equal size affects their morphology and its variability

Silver birch (Betula pendula Roth) seedlings were grown individually in containers arranged in rows radiating from a central point (Nelder plot) at densities spanning the range from 207 to 891 plants m(-2). Height of one set of seedlings was measured at weekly intervals and additional seedlings were harvested each week for dry mass and leaf area measurements. Height and shoot:root dry mass ratio increased with plant density. Seedling-to-seedling variability in dry mass, but not height, increased with increasing plant density. The red to far-red (R:FR) photon ratio in horizontally propagated radiation decreased with increasing density, even when plant densities and leaf area index values were low. In a separate experiment, elongating internodes of seedlings were irradiated locally by red and far-red light emitting diodes and stem elongation measured. Far-red light markedly increased stem elongation, suggesting that changes in light quality sensed by growing internodes are involved in the observed responses to growth density.     

Influence of photosynthetic photon flux density on growth and transpiration in seedlings of Fagus sylvatica

Beech seedlings (Fagus sylvatica L.) were grown in various combinations of three photosynthetic photon flux densities (PPFD, 0.7, 7.3 or 14.5 mol m(-2) day(-1)) for two years in a controlled environmental chamber. Dry mass of leaves, stem and roots, leaf area and number of leaves, and unit leaf rate were affected by both previous-year and current-year PPFD. Number of shoots and length of the main shoot were affected by previous-year PPFD but not by current-year PPFD. Number of leaves per shoot did not change with PPFD, whereas leaf dry mass/leaf area ratio was mainly affected by current-year PPFD. During the first 10 days that newly emerged seedlings were grown at a PPFD of 0.7 or 14.5 mol m(-2) day(-1), transpiration rate per unit leaf area declined. Thereafter, transpiration increased to a constant new rate. Transpiration rate per seedling was closely related to leaf area but the relationship changed with time. In two-year-old seedlings grown at various PPFD combinations of 0.7, 7.3 and 14.5 mol m(-2) day(-1) during Years 1 and 2, leaf area and transpiration rate per seedling were closely correlated at Weeks 7 and 11 after bud burst. Weak correlations were found between root dry mass and transpiration rate per seedling. During Year 2, transpiration rate per leaf area was higher at a particular PPFD in seedlings grown at a previous-year PPFD of 0.7 mol m(-2) day(-1) than in seedlings grown at a previous-year PPFD of 14.5 mol m(-2) day(-1). After transfer of two-year-old seedlings at the end of the experiment to a new PPFD (7.3 or 14.5 mol m(-2) day(-1)) for one day, transpiration rates per leaf area, measured at the new PPFD, were correlated with leaf area and root dry mass, irrespective of former PPFD treatment.     

Effects of Culture Media and Light Intensity on in vitro Growth of Oncidium under CO2 Enrichment Condition

The effects of culture media and light intensity on in vitro growth of Oncidium ‘Aloha Iwanga‘ were investigated under CO2 enrichment condition. Height, fresh and dry weight of the Oncidium seedlings were measured, and the leaf number per plant, shoot number per plant, leaf width and leaf chlorophyll content were also investigated. The results were as follows: 1) The seedling height, fresh and dry weight, leaf number per plant, leaf width and leaf chlorophyll content of the shoots growing on MS complete culture medium were higher than those on 1/2MS, VW and 1/2VW media. The root number per plant and ratio of dry matter of the seedlings cultured on 1/2MS and 1/2VW media were higher than those on MS and VW; 2) The seedling height, flesh weight, dry weight, dry matter ratio and leaf chlorophyll content, leaf length, leaf width, root length, leaf number per plant, root number per plant of seedlings of Oncidium growing under 4 500 lx and 1 700 lx were higher than those under 750 lx. However, there was no significant difference in those growth parameters mentioned above while dealing with 4 500 lx and 1 700 lx except for the seedling height. Nevertheless, the leaf color of plants under 4 500 lx was lighter and the leaves of the lower parts became yellowish in comparison with those growing under 1 700 lx.     

Effects of Seedbed Density on One-Year-Old <Emphasis Type="Italic">Fraxinus angustifolia</Emphasis> Seedling Characteristics and Outplanting Performance

To assess the effects of seedling spacing on one-year-old seedling morphology in the nursery, seeds of three provenances of Fraxinus angustifolia were sown at five different seedling spacings within rows of two different spacings in the seedbed. Subsequent growth performance of one-year-old seedlings was assessed by planting in the forest. Within row spacings were: 4.3, 5.0, 6.3, 8.3, and 12.5 cm, and there were five rows at 20 cm apart, or three rows at 33 cm apart across the 1.2 m wide seedbeds. Both spacings within and between rows significantly affected shoot height, root collar diameter, root dry weight and shoot dry weight, but not root/shoot ratio. Wider spacings produced larger seedlings, but only the wider spacing within rows significantly increased fine and coarse root mass. Provenances showed significant differences in diameter, root/shoot ratio, and fine and coarse roots, and they also showed interactions with row spacings in height and diameter measurements. One year after outplanting, diameter growth was significantly related to provenance, and diameter growth was 88% greater for trees from 33 cm nursery row spacing than those from 20 cm nursery row spacing.     

大叶山杨引种育苗试验研究

大叶山杨是吉林市林科所从长白山地区的山杨种群中选育出来的优良变种，该树种上具有生长迅速、成材早、耐寒、耐瘠簿、适宜地山地生长等优良特性。阜新地区为了丰富山地造要的树种资源，进行了引种育苗试验。结果表明，１年生播种苗和２年生移植苗均表现出原产地原种的优良特性，１年生苗高和地径分别比省标高出８０％和５３％，苗木合格率达９４％；１年生苗总干重大于标准４０．３％，根茎的干重比达１．５６，比一般苗木高出４２     

The effect of seaweed concentrate on the growth of Pinus pinea seedlings

Seedlings of Pinus pinea L. growing in plastic containers were treated with seaweed concentrate (SWC). Different concentrations of SWC were applied, 0 to 3 times, to the roots or shoots of the seedlings. Shoot application increased plant weight mainly by increasing shoot growth. This was manifested as increased shoot length and weight and a decrease in the root/shoot ratio. Root drenches did not change the total plant weight but it accelerated root growth and increased lateral root dry weight. Root growth capacity (RGC) tests for both shoot and root applications indicated an increase in root length and some increases in root number when applied as a root drench. This study indicates that root application of SWC improved seedling quality and increased the ability of seedlings to survive transplanting into pots.Abbreviations GC-MS Gas Chromatography-Mass Spectrometry - RGC root growth capacity - SWC seaweed concentrate     

水曲柳床播不同密度对苗木生长的影响

水曲柳(Fraxinus mandshurica Rupr.)是东北地区三大珍贵硬阔叶用材树种之一,也是东北地区的重要造林树种。研究了不同育苗密度对水曲柳床播苗木生长的影响,结果表明,当密度达到100株/m^2时,为最优育苗密度,其苗高、地径、主根长、侧根数、生物量最优,有利于优质壮苗的培育。     

不同播种密度对楸树砧木梓树幼苗的生长影响研究

对梓树3个种源当年生幼苗进行砧木培育,通过不同密度的播种和移栽,选出在天水地区以种源A最为适宜培育,播种移栽密度以19株/m2为宜,当年生苗木平均地径可达8.85 mm;苗木地径与平均侧根长、地上部鲜质量、地下部鲜质量、地上部干质量、地下部干质量呈正相关性,与苗高、叶数、根数、主根长无显著相关性;各种源苗木生物量与平均侧根长呈正相关,与主根长无显著相关性。