Prediction of planted seedling survival of five Mediterranean species based on initial seedling morphology

Field performance can be predicted by evaluating nursery stock quality, but optimal morphological variables for use in these assessments may vary by species especially under dry Mediterranean conditions. Our objective was to identify initial seedling morphological characteristics that successfully predict field performance of five Mediterranean species (Pinus halepensis, Quercus ilex, Quercus coccifera, Ceratonia silqua and Pistacia lentiscus). Container seedling morphology was evaluated following the nursery phase, and then seedlings were outplanted in the field where field survival was monitored for two successive years. Results indicate that survival can successfully be predicted from seedling initial morphological characteristics for all these species, yet not all the initial characteristics were good predictors. Survival of P. halepensis and Pist. lentiscus seedlings was positively correlated to initial seedling root-collar diameter, total dry weight and Dickson’s quality index, and can be reliably predicted by these variables. In contrast, seedling field survival of the two Mediterranean evergreen oak species was correlated with few initial morphological attributes; initial diameter provided an accurate index to predict second-year outplanting survival for both species while height/diameter was a good survival predictor for Q. coccifera seedlings. For C. siliqua seedlings, seedlings with larger initial diameter and total biomass survive better in the field. Thus, diameter was the common variable that accurately predicted survival for all species, which should be >5 mm for P. halepensis seedlings and >7 mm for the remaining species.     

紫薇的育苗及栽培管理技术

概述了紫薇的观赏特性，园林用途，生态习性以及扦插，播种，分株等育苗技术，介绍了紫薇的栽植，浇水，施肥，修剪整形，花期调控和病虫害防治等方面的栽培管理技术。     

STUDY ON RELATIONSHIPS AMONG SEEDLING QUALITY AND SURVIVAL RATE, STOCKING PERCENTAGE AND GROWTH

Seedlingqualityisoneofthemostimportantfactorsinfluencingonthesurvivalrateandstockingpercentageinafforestationespecially,thequalityofseedlingmakesgreateffectsonthegroWthofdiameterandheightdirectlyincultivatinghighyieldandfastgrowthplantation.korqanpine,mongolianscotspine,dahurianlarch,koreanspruce,manchurianash,anurcorktreeandanurlindenaremainbroadleafandconiferousspeciesforwoodinNortheastofChina.Thisisbecausethatthesespeciesnotonlyhavegoodtimberqualityandfastgrowth,butalsohavehighereconomicva…     

Effects of presowing treatments, desiccation and storage conditions on germination of Strychnos nux-vomica seeds, a valuable medicinal plant

Seeds of Strychnos nux-vomica have slow and erratic germination; thus different presowing treatments were applied to enhance the germination of its seeds collected from Tamaraikulam, Tamil Nadu, India. In addition, the effects of desiccation and different storage conditions on the germination of S. nux-vomica seeds were investigated. The results show that soaking in 500 ppm gibberellic acid (GA₃) for 24 h, incubation of seeds at 40 °C for 3 days and alternate water soaking (16 h) and drying (8 h) for 14 days significantly increased the percentage germination compared to the control. Desiccation of seeds down to 10% moisture content resulted in better germination. Germination of S. nux-vomica seeds differed significantly between different storage periods, moisture contents of the seed and for first and second order interactions (p<0.001). The highest germination (92%) was achieved when seeds with 10% moisture content were stored at ambient temperature for 30 weeks. Evidence from the present study indicates that S. nux-vomica seeds possess physiological dormancy that can be broken effectively by after-ripening. As seeds of S. nux-vomica are found to be desiccation tolerant, dry seed (10% moisture content) can be hermitically stored at ambient temperature for 30 weeks without losing their viability.     

Diversity of woody plant seedling banks under closed canopy in fragmented coppice forests

? Seedling banks of woody species established under closed canopy have received little consideration in coppice forests despite their potential importance for natural regeneration.

? This study aimed to evaluate the influences of canopy composition and of distance from the nearest forest edge on the abundance and species richness of the seedling bank, for different ecological groups of seedlings (age, successional status and dispersal vector) in 68 fragmented coppice stands.

? Seedlings were found in 67 stands, with 19 species identified. Eight species present as older seedlings were lacking as first-year old seedlings, suggesting temporal variability of species recruitment. Seedling abundances of species with low-dispersal ability were positively correlated with the abundances of their conspecific adults. Seedling abundance of mid-successional species was negatively correlated with the distance from the nearest forest edge, while mid-to-late successional species seedling abundance presented the opposite pattern.

? Our results showed that woody species were able to establish frequently under closed canopy in these fragmented coppices and form a seedling bank which may be used for natural regeneration.

     

Factors influencing levels of genetic diversity in woody plant species

The plant allozyme literature was reviewed to: (1) compare genetic diversity in long-lived woody species with species representing other life forms, and (2) to investigate whether the levels and distribution of genetic diversity in woody species are related to life history and ecological characteristics. Data from 322 woody taxa were used to measure genetic diversity within species, and within and among populations of species. Woody species maintain more variation within species and within populations than species with other life forms but have less variation among populations. Woody species with large geographic ranges, outcrossing breeding systems, and wind or animal-ingested seed dispersal have more genetic diversity within species and populations but less variation among populations than woody species with other combinations of traits. Although life history and ecological traits explain a significant proportion (34%) of the variation among species for the genetic parameters measured, a large proportion of the interspecific variation is unexplained. The specific evolutionary history of each species must play an important role in determining the level and distribution of genetic diversity.     

Forest loss and fragmentation effects on woody plant species richness in Great Britain

Studies on the effect of forest loss and fragmentation on plant species richness at different spatial scales have yielded contradictory results that have been attributed to different ways to measure fragmentation. The main goal of this study was to investigate the independent and combined effects of forest loss and habitat fragmentation on woody species richness. Woody species were grouped according to their habitat requirements (forest specialists, forest generalists, non-forest and total woody species). We used regression models to investigate the effect of fragmentation and human occupation on woody species richness. The underlying factors were investigated by partitioning of the variation, i.e. decomposing the variation in species richness between the pure effects of forest loss, fragmentation and human occupation. The relationship between species richness and forest loss resulted extremely non-linear. The models for forest specialist, generalist and total woody species richness accounted for 35%, 31% and 33% of the total variance respectively. Model for non-forest species richness only accounted for 7% of the total variance. The largest fraction of variability in species richness was accounted by fragmentation variables for all groups (except for non-forest species). Results emphasize the larger independent effect of fragmentation over forest loss, suggesting that species variation is mainly conditioned by the spatial configuration of the habitat.     

Effect of warm storage and date of lifting on the quality of Douglas-fir seedlings

The effect of warm storage (15 °C)for up to 21 days on the vitality of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) seedlings lifted on four occasions from October to January wasassessed using fine root electrolyte leakage (REL). After 0, 7 and 21 days warm storage, additionalseedlings were potted and placed in a controlledgreenhouse environment to determine root growthpotential (RGP) after 4 weeks and survival after 8weeks. REL was a poor indicator of survival potential;REL increased after 7 days storage, despite the factthat RGP and survival were unaffected. REL increased further during the remainder of the 21-days storage period, but values were often not greatly different from those following 7days storage. Storage for up to 21 days greatlydecreased RGP and survival. Seedlings lifted inOctober and November were most affected by storagetreatments, but differences among lifting dates wererelatively small.     

栽植密度对黄檗苗期生物量的影响

以黄檗3 a生幼树为材料,对不同栽植密度的生物量进行研究,结果表明:栽植当年和翌年秋季的成活率与保存率分别为92%和91%。不同株距树高、地径生长量均达到极显著差异(P0.01),树高、地径生长量从大到小顺序依次为株距0.5 m1 m0.3 m1.5 m;而不同行距对树高、地径生长量均无影响。采用一元生物量模型计算生物量,总生物量最大的种植密度为33 300株·hm~(-2)(株行距0.3 m×1.0 m),可产生干物质3 930.06 kg·hm~(-2);最小的为3 300株·hm~(-2)(株行距1.5 m×2.0 m),干物质仅为344.08 kg·hm~(-2)。     

Effect of sowing date on seedling emergence of species with seeds enclosed in a stony endocarp

The aim of the present study was to investigate the effect of the natural sequence of temperature conditions between the time of seed sowing and their germination on dormancy release of Prunus avium, P. mahaleb, P. divaricata, P. laurocerasus, P. spinosa, Cornus mas, C. sanguinea, and Celtis australis seeds which are enclosed in a hard stony endocarp. According to their collection date, the seeds (with the endocarp) of the above species were sown outdoor in summer, autumn, and winter and the number of emerged seedlings was counted during the following two springs. For all species, the first sowing date was immediately after seed collection and cleaning. In all species, seedling emergence occurred in early spring and dormancy was released only after the exposure of seeds to specific season conditions. The exposure of seeds of all studied species, except C. australis, to a period of warm temperatures prior to winter was necessary for dormancy breaking and germination. Autumn sowing of P. laurocerasus and C. sanguinea seeds, which were collected in summer, and the sowing immediately after seed collection of the rest species, resulted in a maximum percentage of seedling emergence in the following spring.     

Comparison of different site preparation techniques: quality of planting spots,seedling growth and pine weevil damage

In northern Europe, there are high risks of severe pine weevil (Hylobius abietis) damage to newly planted conifer seedlings. Site preparation is one of the most important measures for reducing these risks and as several studies have shown the damage is highly dependent on the amount of pure mineral soil around the seedlings. We investigated effects of three site preparation techniques: (1) disc trenching with a conventional Bracke T26, (2) MidiFlex unit and (3) soil inversion with a Karl Oskar unit on characteristics of the planting spots, growth and pine weevil damage and survival rates of untreated and insecticide treated planted Norway spruce (Picea abies) seedlings. All three site preparation techniques reduced pine weevil damage in comparison with no site preparation, and the proportion of spots with pure mineral soil they created was inversely related to the rate of mortality caused by pine weevil. The results indicate that the quality of the planting spots depends on the technique used. In areas where pine weevil is the major threat to seedling survival, the amount of mineral soil in the planting spots is the most important factor in order to protect the seedling from damage. Without site preparation most planting spots consisted of undisturbed humus. Generally, the Karl-Oskar created the most spots with pure mineral soil, but on very stony soils the Bracke T26 created more mineral soil spots than other methods. Site preparation is a valuable tool in order to improve survival in regeneration areas and it is of great importance to make the right choice of technique depending on the particular circumstances on the actual site.     

大苗带冠幅栽植技术要点

通过调查近年来八百里绿色行动造林中大量采用带冠幅绿化大苗进行造林的实际情况,浅述了带冠幅绿化大苗栽植的含义,并对树种的选择以及在栽植过程中对绿化大苗的起运、修剪、栽植和管理等技术进行了分析。     

容器育苗造林技术

该项技术分为容器育苗和容器苗造林两部分。主要技术包括：容器制做；配制基质（营养土）；种子处理与播种；容器苗的水、肥管理；容器苗造林等措施。运用容器育苗造林技术，能够提高苗木繁育系数、质量和造林成活率，延长当年的造林时间，加速荒山绿化进程。     

林业苗圃地连作和轮作对苗木生长及土壤肥力影响的研究

研究了林业圃地连作与轮作培育杉木、酸枣、厚朴等苗木的生长状况及土壤肥力的变化。结果表明:用水稻等作物与杉木轮作后,杉木苗生长状况改善,土壤有效养分和速效养分增加。     

固定沙地樟子松容器育苗及造林技术研究

樟子松容器苗造林是一项实用高效的林业造林生产技术,对半干旱固定沙地较为适宜。文章介绍了樟子松容器育苗技术及容器苗造林技术,旨在提高樟子松育苗成活率,并在当地推广此项技术。     

播种时期对蒙古栎不同类型苗木出苗和生长的影响

以蒙古栎种子为材料,研究播种时期对蒙古栎不同类型苗木出苗和生长的影响,结果表明:蒙古栎在秋季不同时间播种的出苗率均在60%以上,但以早期(9月下旬)播种的出苗率最高(大于80%),早期播种的苗木在苗高、地径、侧根数、根体积和根生物量等指标上都明显要高于其它播种时期,蒙古栎在秋播裸根育苗时应适时早播;秋季播种的容器苗在所有观测的形态指标上均好于春季播种的容器苗,秋季容器育苗质量更高。     

Biomass accumulation and nutrient uptake of 16 riparian woody plant species in Northeast China

Our research focused on eutrophication control and species screening for riparian zone vegetation restoration in the upstream reach of the Hun River. We studied 16 hardwood plant species to investigate nutrient concentrations and nitrogen and phosphorus accumulations. After about 120 days of growth in pots, these 16 species varied in dry matter biomass, ranging from 15.13 to 637.16 g. Total nitrogen （TN） and total phosphorus （TP） concentrations and distribution in roots, stems and foliage differed both within and between tested species. Mean TN and TP accumulation ranged from 0.167 to 14.730 g per plant and from 0.016 to 1.20 g, respectively. All 16 species, but especially Lespedeza bicolor, Robinia pseudoacacia and Sorbaria sorbifolia had strong potential to remove TN and TP from soil and could be widely utilized for the restora- tion of destroyed riparian zones in northeast China.     

木本植物VA菌根研究进展

综述了近年来国内外有关木本植物VA菌根的研究进展,其中包括木本植物VA菌根资源和VA菌根的生理生态学特性,并探讨了VA菌根在农林业生产上的应用方法、策略及其前景。