苗期机械拂擦处理对蔬菜植株生长和发育的影响

探明育苗期应用机械拂擦处理代替植物生长延缓剂矮化植株、控制幼苗徒长的可能性。机械拂擦处理强度通过接受处理时间迟早及塑料刷片密度高低来调节。结果表明机械拂擦处理显著延缓植株生长 ,缩短植株节间长度 ,提高茎粗和株高比。甜椒、番茄、黄瓜对机械拂擦处理的敏感性不一 ,生长延缓程度随着处理强度的增加而增加。机械拂擦处理对始花期有一定的影响 ,但对果实产量无不良影响     

几种复合育苗基质特性及其在生菜上的育苗效果

将蛭石、炉渣灰、细砂、草炭和有机肥等按照不同组合与配比组成复合基质 ,用于生菜穴盘育苗。结果表明 ,不同基质对生菜幼苗生长影响有明显差异。复合基质T2 (蛭石∶有机肥∶炉渣灰 =7∶2∶1)育苗效果最佳 ,明显好于CK(草炭∶蛭石 =2∶1) ,表现为幼苗生长迅速 ,干物质积累快 ,壮苗指数大。因此 ,T2 可代替CK用于工厂化穴盘育苗 ,T3 、T7的育苗效果次于T2 ,而优于CK ,亦具有利用的价值     

蓝浆果扦插育苗技术比较研究

运用正交试验对ABT生根剂处理蓝桨果插条的处理浓度、处理时间、枝条类型和扦插基质4个因素进行了比较,结果表明,生根剂不同浓度,不同枝条类型和不同扦插基质对蓝浆果扦插育苗成活率有显著影响,在南昌地区9月中旬开展蓝浆果扦插育苗,选取当年生春梢做插条,采用ABT生根剂100mg/kg或50mg/kg处理插条4h或8h,并扦插在黄心土上,能有效提高成活率。     

Critical RGC-Expected Survival models for predicting Survival of planted white fir (Abies concolor Lindl.) seedlings

Heretofore, only regression models using average RGC as the independent variable were available to predict the survival of planted seedlings. Now, however, Critical RGC-Expected Survival models are available. Each model predicts the survival of a population on sites with the same Critical RGC as specified by the model. Survival is predicted to equal the percent of the seedlings in the population that have RGCs that Critical RGC. These models are validated by a chi-square goodness of fit test which determines the probability that the survival predictions made by a model agree with the survivals observed on a planting site. In validating a model, the harshness of the planting site is also quantified in terms of its Critical RGC. In this paper, three Critical RGC-Expected Survival models are validated, demonstrating that RGC controls survival on both harsh and gentle sites. On the harsher sites, the Critical RGC for survival was 40 cm; whereas on the gentler sites, it was 20 cm.     

Nitrogen and phosphorus leaching and uptake by container birch seedlings (Betula pendula Roth) grown in three different fertilizations

Leaching of nitrogen (N) and phosphorus (P) through container peatmedium and N and P uptake by seedlings were determined in commercial productionof birch grown with three different types of fertilization. Half of the amountof nutrients was premixed into the peat medium and the other half was appliedasliquid (=fertigated) in the treatment (PF) commonly used in Finland. In twoother treatments all nutrients, either totally (P-VN) or partly (P-N) inslow-release form, were premixed into the peat. Independently of the treatment,the largest proportion (60 to 80%) of total N leached during May and June.During two growing seasons, the amounts of N leached from PF treatments (9 to36kg ha^–1) were as large as the amounts of Nleachedfrom P-VN and P-N treatments (24 to 46 kg ha^–1).Due to fertigations between container trays, however, the total N load perhectare was greatest in the PF treatments. In the soil water 0.5meter beneaththe container area, the N concentration varied from 10 to 60 mgl^–1. The morphological and chemical properties of theseedlings did not differ greatly between treatments.     

Effects of a nursery CO2 enriched atmosphere on the germination and seedling morphology of two Mediterranean oaks with contrasting leaf habit

The use of an enriched CO₂ atmosphere in tree nurseries has been envisaged as a promising technique to increase productivity and to obtain seedlings with a higher root/shoot ratio, an essential trait to respond to water stress in Mediterranean-type ecosystems. In that framework, we have analyzed the effects of three levels of atmospheric CO₂ concentration (350, 500 and 700ppm) on the germination rate, growth and morphology of seedlings of two Mediterranean oaks used in reforestation programs: the evergreen Quercus ilex L. and the deciduous Quercus cerrioides Wilk. et Costa. CO₂ enrichment increased the germination rate of Q. cerrioides (from 70±7 to 81±3%) while it decreased that of Q. ilex (from 71±10 to 41±12%). Seedlings of both species increased approximately 60% their total biomass in response to CO₂ enrichment but at two different CO₂ concentrations: 500ppm for Q. cerrioides and 700ppm for Q. ilex. This increase in seedlings biomass was entirely due to an augmentation of root biomass. Considering germination and biomass partitioning, an enriched CO₂ atmosphere might not be appropriate for growing Mediterranean evergreen oaks, such as Q. ilex, since it reduces acorn germination and the only gains in root biomass occur at a high concentration (700ppm). On the other hand, a moderate CO₂ enrichment (500ppm) appears as a promising nursery technique to stimulate the germination, growth and root/shoot ratio of deciduous oaks, such as Q. cerrioides.     

引种美洲黑杨无性系的苗期遗传测定与选择

９７个美洲黑杨无性系经苗期测定结果表明：苗高、地径的生长，表现出无性系间的显著差异，具有较丰富的遗传变异基础，广义遗传力分别为８０．２３％和７２．９９％，二性状间表现出极显著的遗传相关。以苗高的ＬＳＤ多重比较，选择出生长最好的４１个无性系，其苗期生长水平超过或相当于中林２３杨；用苗高和地径的综合指数选择，淘汰生长最差的２９个无性系，保留的６８个无性系作为育种资源保存。     

Genetic aspects of artificial regeneration of Douglas-fir (Pseudotsuga menziesii) in Bavaria

Douglas-fir has been planted in Bavaria for over 100 years. Its high growth potential and good wood quality combined with its silvicultural characteristics have increased interest in the species which can easily be integrated into existing natural ecosystems. In order to be successful in the establishment of Douglas-fir one must select the best provenance (only the so called “green” or viridis coastal type form is suitable for Bavaria), maintain a broad genetic base and carry out proper silviculture. The goal of the study was to check the origin/provenance (coastal or interior type) of older Bavarian Douglas-fir stands, the respective genetic variation of the stands and also the natural regeneration, the collected seed and the plants raised in the nursery. Possible changes in the genetic composition and diversity due to selective processes in the nursery phase were also investigated. Isoenzyme gene markers were used for the study. The majority of the investigated older stands apparently belong to the coastal type Douglas-fir; however, we also found mixed stands and stands solely of the interior (unsuitable) type. Older stands show large variation in their genetic diversity (v _gam between 19.9 and 90.1). Some of the stands of unsuitable provenance have natural regeneration and others have been selected as seed collecting stands. Through natural regeneration the genetic structure of the older stands is passed on to the following generation. The same is true for reproductive material collected from such stands. In comparison to seed collected from stands in the USA (from stands selected by the EU for seed collection), seed from Bavarian stands is genetically very heterogeneous in respect to the allele variants and the diversity. No significant changes in the genetic population structure were found in the nursery due to sowing or transplanting. The critical stage for obtaining high quality reproductive material of Douglas-fir is the selection of seed collecting stands and the harvesting procedure. The resulting consequences for seed collection and procurement of suitable reproductive material for Douglas-fir are discussed.     

香榧苗圃地除草剂筛选试验

为提高香榧苗圃地杂草的防除效果,保护苗木,降低用工成本,选用普通市售除草剂,采用随机区组和正交设计筛选对香榧苗木无害且有效的除草荆单荆和组合.结果表明:(1)推荐剂量范围内不同除草剂对香榧苗圃地杂草都有一定的防除效果,药后第28天的株防效在57.46%～74.63%之间.果尔、百草枯的株防效较好,时效较长,可以选用;草甘膦的短时株防效最高,但时效短;精稳杀得起效较慢.(2)不同浓度除草剂混用后的除草效果比单剂好,药后第28天的株防效在84.32%～94.74%,筛选出的24%果尔乳油(1 050 mL/hm2)+10%草甘膦水剂(16 500 mL/hm2)+15%精稳杀得乳油(450 mL/hm2)复配剂除草效果最佳.(3)香榧苗圃地使用除草剂对苗木生长无影响,而且工效高,伤苗少,成本低,相对人工除草降低1 950 元/hm2以上.     

长沙城市森林建设树种大树移栽圃地囤积调查及思考

文章介绍了长沙城市森林建设树种大树移栽、圃地囤积的树种种类、来源、数量、规格、成活率和参考价格等,并对大树移栽中存在的问题提出了整改意见。