对节白蜡新品种“京翠”繁育技术

指出了对节白腊新品种“京翠”具有树型优美、不须修剪、自然成型的特点。介绍了嫁接繁育新品种“京翠”苗木的方法。从定植砧木、采集接穗、嫁接方法、培育管理、病虫害防治等环节详细探索了实际操作流程、方法和注意事项。以期形成一项较成熟的“京翠”品种繁育推广技术。     

大叶白蜡树锈病及其重寄生菌研究

 小叶白蜡树锈孢锈菌(Aecidium fraxinibungeanae Diet.)引起大叶白蜡树(Fraxinus chinensis var.rhynchophylla Hemsl)锈病为国内新记录。该锈病在我国重要白蜡产区乐山市严重发生,病株率和病叶率分别可达100%和56%,造成叶片病部坏死,病叶脱落,严重影响白蜡产量。大叶白蜡树锈病菌的重寄生菌(Tuberculina sp.)为国内外首次报道。该重寄生菌在乐山市及雅安市大叶白蜡树锈病菌上寄生很普遍,自然重寄生率达46.8%。重寄生菌寄生在大叶白蜡树锈菌春孢子器(锈子器)出口处,阻碍春孢子(锈孢子)的释放。本文还报道了大叶白蜡树锈病的危害、症状特点、病原形态特征及大叶白蜡树锈病菌的重寄生现象和重寄生菌形态特征。     

新疆小叶白蜡育苗造林试验初报

宁夏于2001年从新疆引进新疆小叶白蜡,在平罗县进行育苗试验。通过4年的试验,播种育苗和移植育苗取得了成功,苗木长势良好;苗木的造林成活率当年达到了86%。     

Effects of elevated CO2 concentrations on photosynthesis, dark respiration and RuBPcase activity of three species seedlings in Changbai Mountain

Two-year-old seedlings ofPinus koraiensis, Pinus sylvestriformis andFraxinus mandshurica were treated in open-top chambers with elevated CO₂ concentrations (700 μL·L⁻¹, 500 μL·L⁻¹) and ambient CO₂ concentrations (350 μL·L⁻¹) in Changbai Mountain from June to Sept. in 1999 and 2001. The net photosynthetic rate, dark respiration rate, ribulose-1,5-bisphosphate carboxlase (RuBPcase) activity, and chlorophyll content were analyzed. The results indicated the RuBPcase activity of the three species seedlings increased at elevated CO₂ concentrations. The elevated CO₂ concentrations stimulated the net photosynthetic rates of three tree species exceptP. sylvestriformis grown under 500 μL·L⁻¹ CO₂ concentration. The dark respiration rates ofP. koraiensis andP. sylvestriformis increased under concentration of 700 μL·L⁻¹ CO₂, out that ofF. mandshurica decreased under both concentrations 700 μL·L⁻¹ and 500 μL·L⁻¹ CO₂. The seedlings ofF. mandshurica decreased in chlorophyll contents at elevated CO₂ concentrations. Foundation item: This paper was supported by the National Natural Science Foundation of China (No. 30070158). Knowledge Innovation Item of Chinese Academy of Sciences (KZCX2-406) and “Hundred Scientists” Project of Chinese Academy of Sciences. Biography: Zhou Yu-mei (1973-) Ph. Doctor, Assistant Research fellow Institute of Applied Ecology. Chinese Academy of Sciences. Shenyang 110016. P.R. China. Responsible editor: Song Funan     

Detecting forest stress and decline in response to increasing river flow in southwest Florida, USA

Forest stress and decline resulting from increased river levels were investigated in Myakka River State Park (MRSP), FL, USA. Since 1977, land-use changes around the upper Myakka River watershed have resulted in significant increases in water entering the river, which have caused extensive mortality in the upper watershed. The present study assessed whether similar forest stress and mortality was occurring downstream within the park. Our objectives were to (1) determine if tree die-off and/or stress resulting from increased river levels were present in MRSP and (2) determine the relationship between historical and present river levels regimes and growth of actively managed forested stands undergoing restoration located both above and below a dam. We used two methodological approaches. The first was recording indications of tree stress and decline (crown dieback, crown thinning, trunk rot, foliage discoloration, and parasitism) in Fraxinus caroliniana Miller dominated forested wetlands, Pinus elliottii Englem. var. densa Little & Dorman dominated mesic pine flatwoods, and Quercus laurifolia Michaux dominated oak palm hammocks. Our second approach was tree-ring analyses, which allows for more detailed analyses of growth in response to precipitation and river flow (a surrogate variable for water table depth) in the pine flatwoods stands.

Our results indicate significant stress and decline in some forested wetlands upstream of the dam, significant mortality in wet-mesic pine flatwoods sites close to the river, and significant amounts of stress in wet-mesic pine flatwoods sites upstream of the dam. F. caroliniana sites located upstream of the dam had more individuals with symptoms of stress than those downstream of the dam (67% versus 43%, P=0.031). In Q. laurifolia sites, 70–85% of the trees had evidence of flooding stress and mortality, which is comparable to distributions found in severely disturbed forest in the upper watershed. P. elliottii var. densa sites located <1000 m from the river had higher mortality than sites located >1050 m from the river (P<0.01), and the stressed trees in sites upstream of the dam had significantly lower growth rates in the 1990s versus the 1960s than those downstream. Although, the onset of stress and decline coincided with increasing river levels, we found that river levels were positively correlated with tree growth, both before and after flow increases in the system. Increasing river levels may play an indirect role through increased competition in the stress and decline in wet-mesic pine flatwoods, however, increased river levels seems to be the direct cause for stress and decline found in forested wetland stands.     

对节白蜡多年生枝干扦插研究

报道了对节白蜡3～8a生粗大枝干的不同药剂处理对扦插生根的影响。实验表明：该种对生根剂反应敏感，其中NAA200ppm速蘸等处理明显促进扦插生根。扦插苗适用于制作观赏用盆景的桩坯。     

Endogenous inhibitors in seed ofFraxinus mandshurica Rupr and their effect on germination and regeneration

Bioassay and GC-MS determination indicated that inhibitors of seeds ofFraxinus mandshurica Rupr were distributed mainly in zones of β-inhibitors (including ABA) and of high and low R_f value. The inhibitory activity of outer seed coat of the dormant seed (control treatment) was higher than that of seeds with only the inner coat attached e.g. ABA was 114 and 54ng/g fresh weight respectively. The inhibitory effect of No. 12 zone was even higher than ABA. The inhibitory activity of all the zones decreased after stratification (St) and burying (A0) treatment, especially that of the outer seed coat, whose ABA content decreased to 7(St) and 11 (AO) ng/g(fw). However, the decrease in inhibition of root growth lagged behind the decrease in germination. It is concluded that burial is advantageous to regeneration. Inhibitors of the outer seed coat and seeds were mostly destroyed under the adverse conditions of natural dissemination (Di treatment) indicating that Di was not conducive to regeneration. MS analysis revealed that the largest peaks of No. 6, 7 and 12 zones were linolcic acid, olcic acid and 17-C, 18-C, and 20-C long chain fatty acids. Several coumarins were found in No. 6 and 7 zones, and cadinencs, farnesol and sesquiterpenes were found in No. 6 and 12 zones having common bioorigins with ABA.     

不同立地条件下水曲柳人工林生长状况的初步研究

不同立地条件的水曲柳人工幼龄林生长指标的调查结果表明:缓坡造林,8 a生胸径最大值为6.0 cm,树高最大值为6.5 m;轻微水湿地造林,经2次施肥后,12 a生时平均胸径、平均枝下高生长量较缓坡造林的8 a生水曲柳仅具有微弱生长优势,平均树高、平均冠幅和平均枝下高低于8 a生缓坡水曲柳幼龄林;农耕地10 a生水曲柳人工幼龄林平均树高为4.50 m,为其他立地的150%,最大值为6.8 m,胸径最大值为7.3 cm,单位面积立木蓄积为其他立地的158.3%。水曲柳造林后第四年开始,胸径、树高、材积生长较快,胸径连年生长量由0.65 cm增至0.80 cm以上;树高生长量在4~6 a增长最大,连年生长量达1.00 m,平均生长量也持续在0.60 m以上;材积平均生长量、连年生长量自第四年开始,增幅较大,第六年连年生长量为第五年的1.92倍。     

The influence of chemical soil factors on the development of VA mycorrhizas of ash (Fraxinus excelsior L.) and sycamore(Acer pseudoplatanus L.) in pot experiments

The objectives of this study were (1) to investigate effects of soil acidity on the formation of mycorrhizas in ash and sycamore, and (2) to elucidate if mycorrhization can improve the acquisition of Ca, Mg, and P by these tree species. Soil substrates with different Ca, Mg, and Al saturation were used in pot experiments with mycorrhizal ash and sycamore seedlings and various Ca and Mg fertilization treatments. The development of vesicular‐arbuscular‐mycorrhizas (VAM) in both species was considerably affected by the chemical soil properties and by the nutritional status of the plants. Mycorrhizal fungi developed well only in plants growing on basalt‐derived, Ca and Mg rich loam and in substrates fertilized with Ca and Mg carbonate. In these substrates, the pH value, Ca and Mg supply and growth of the plants were optimal. The mycorrhizas degenerated in an acid loam derived from phyllite, in tertiary sand and in all treatments receiving Ca and Mg sulfate. Ash and sycamore suffered from Ca and Mg (P) deficiency, and partly from Al antagonism against Ca and Mg uptake (sycamore) or Al toxicity (ash). The symbiosis between fungi and the plants was disrupted since the tree species and the VAM fungi (from fertile nursery soils) did not adapt to the acidic experimental soil substrates with high Al activity. Consequently, the fungi lost their function of supporting the plants by improved nutrient uptake and the plants likely did not produce enough organic substances for the fungi. In addition, N fertilization possibly suppressed the development of VA mycorrhizas and inhibited new colonization in acid substrates.     

水曲柳春季播种育苗技术

在对水曲柳育苗实践经验进行总结的基础上,提出了一种隔两年沙藏层积处理种子催芽的春播育苗技术。笔者从种子采集与处理、圃地选择与整地、播种方法、苗期管理等方面进行了详细的阐述,为该树种的应用推广提供了参考。