植物生长调节剂对格药柃硬枝扦插繁殖的影响

研究了NAA、IBA对格药柃硬枝扦插繁殖的影响.结果表明,选择适当浓度的外源植物生长调节物质可显著提高格药柃硬枝扦插繁殖效果.其中用1000mg/L质量浓度的吲哚丁酸溶液速浸5min插穗,其生根率可达76.67%.     

壳聚糖对小麦发芽及生根效应的研究

利用壳聚糖浸泡小麦种子,通过考察小麦的出芽率、发芽指数、活力指数、生根数量和根的长度等各项指标的变化,探讨壳聚糖对小麦发芽和生根生理效应的影响.结果表明,当pH值6.5、壳聚糖浓度为4-6mg/mL时能显著提高小麦种子活力,促进幼苗生长;当壳聚糖浓度低于8mg/mL时,小麦的出芽率、发芽指数、活力指数随壳聚糖处理浓度的增大而明显提高;当壳聚糖浓度为4mg/mL、浸泡时间为10h时,小麦种子生根效应最为明显.     

千层塔扦插繁殖研究

通过扦插试验,采用不同浓度水平的吲哚丁酸、萘乙酸、生根粉和吲哚丁酸＋萘乙酸等药剂处理千层塔插条,研究对插条的生根量、生根率、成活率等的影响和插条萌芽状况及扦插基质对插条生根的影响,为千层塔资源快速再生提供有效的繁殖途径。     

正交设计在峨眉金线莲组织培养中的应用

以野生峨眉金线莲的茎段腋芽为外植体,采用正交设计L16(4~5)对野生峨眉金线莲丛生芽诱导、生根的4个因素(基本培养基、6-BA、NAA、AC(活性炭))在4个水平上进行组织培养优化试验,以期建立完整、高效、廉价的培养体系。结果表明:基本培养基、不同激素浓度配比等因素对峨眉金线莲的分化、生根有着显著影响。外植体最佳消毒方案是75%酒精浸泡10s,0.1%的HgCl_2浸泡消毒10min;峨眉金线莲最佳丛生芽诱导培养基为:MS+10%香蕉+6-BA3mg/L+NAA 0.5mg/L+AC 3g/L;最佳生根壮苗培养基为:1/2MS+10%土豆+NAA 2mg/L+6-BA 0.5mg/L+AC 3g/L。该体系对峨眉金线莲种质资源保护与开发利用具有一定的参考意义。     

紫色甘薯茎尖培养一步成苗技术研究

以紫色甘薯茎尖为外植体，MS为基本培养基，附加不同浓度NAA与BA两种激素对一步成苗培养基进行优化，筛选出一步成苗最佳培养基MS＋0．2mg／LBA＋0．5mg／LNAA，约3d左右诱导愈伤组织，15—20d分化幼苗、生根，约45d后就可一步成苗，直接发育成完整植株，最高成苗率为11．4％。对这种培养基上的再生小植株进行移栽，1个月后其移栽成活率达100％。     

大蒜脱毒种苗的快速繁殖方法

本方法包括 :取未熟蒜苔为外植体 ,通过对不同培养基、培养时间的选择 ,糖种类及浓度、激素配比的改变 ,新型植物激素茉莉酸及水杨酸的应用 ,可同时获得大量的大蒜脱毒试管苗 ,繁殖基数达 50～ 76,试管鳞茎诱导率达 80 %以上 ,鳞茎鲜重 30 0ｍｇ以上。所形成的鳞茎可直接移栽到     

几种激素对光合细菌生长的影响

提出在培养基中添加一定浓度的动物或植物生长激素可促进光合细茵的生长。泼尼松、地塞米松、三十烷醇、α-萘乙酸的最适添加浓度分别为0．5mg／L，1mg/L，0．5mg/L和0．5mg/L。混和激素促生效果好于单一激素。指出在生产性培养中，添加某些激素促进光合细茵的生长是可行的。     

豆腐柴生根的营养条件筛选

分别以一年生和两年生豆腐柴枝条上切段和下切段为材料,将1/50、1/20和1/10 hoagland大量元素、微量元素和铁盐以及24μM、48μM和96μM硅酸进行4因素3水平正交试验,培养豆腐柴枝条,诱导其生根.结果表明,一年生材料生根率高于两年生材料,下切段生根率高于上切段.Hoagland铁盐最为重要,其次为Hoagland大量元素,第三为硅酸,Hoagland微量元素作用不大.豆腐柴不定根诱导的最佳组配为1/10Hoagland大量元素+Hoagland铁+48μM硅酸.     

济南市区加油站附近空气中有机污染特性研究

通过研究济南市市区某加油站邻近空气中挥发性有机物浓度的分布情形,分析加油站作业过程对周围环境空气的影响.结果表明:在加油等操作过程中,逸散排放的挥发性有机物主要为苯类污染物,其最大浓度值出现在逸散源附近,上风向浓度较下风向低,且种类较少.     

壳聚糖对花生三种防御酶含量的影响

用不同浓度的壳聚糖溶液对花生种子进行包衣,然后测定在其萌发阶段种子内的苯丙氨酸解氨酶(PAL)、过氧化物酶(POD)、过氧化氢酶(CAT)等主要活性的变化.结果表明,壳聚糖处理花生种子可明显提高花生PAL、CAT的活性,对POD影响不显著.各种防御酶在5天内比空白对照组出现较明显的增加,说明外源壳聚糖提高了花生种子的防御酶活性,使花生得到更强的抗病性.     

砷超富集植物蜈蚣草的离体培养及植株再生

探讨了蜈蚣草组织培养的最佳孢子萌发培养基、初代培养基、最佳继代培养基、生根培养基。结果表明,蜈蚣草孢子在1/2MS孢子萌发培养基上萌发效果最好,经初代培养后最佳继代培养基为1/2 MS+6-BA 0.5mg/L+NAA 0.2mg/L,经生根培养后炼苗移栽成活,因此通过孢子组织培养成为蜈蚣草幼苗快速繁殖的最佳途径。     

植物激素对平菇茵丝生长及酶活性的影响

采用固体平板和液体摇瓶培养方法,研究了赤霉素、2,4-D、吲哚乙酸和萘乙酸4种激素对平菇- 126菌丝生长及酶活性的影响.结果表明,吲哚乙酸虽然能提高发酵液胞外蛋白的含量和过氧化物酶活性,但对菌丝的生长起抑制作用,这与吲哚乙酸能引起平菇菌丝裂解和细胞膜渗漏有关;萘乙酸、低浓度2,4-D能促进菌丝的伸长;萘乙酸、赤霉素在低浓度下也能促进菌丝的分枝,对菌丝的生长整体上起促进作用.除吲哚乙酸外,其他3种激素对平菇菌丝生长影响都有两重性:低浓度下能促进菌丝的生长,浓度过高则会对菌丝生长产生毒害作用.     

Nitrogen leaching from Douglas-fir forests after urea fertilization

Leaching of nitrogen (N) after forest fertilization has the potential to pollute ground and surface water. The purpose of this study was to quantify N leaching through the primary rooting zone of N-limited Douglas-fir [Pseudotsuga menziesii (Mirb.) Franco] forests the year after fertilization (224 kg N ha(-1) as urea) and to calculate changes in the N pools of the overstory trees, understory vegetation, and soil. At six sites on production forests in the Hood Canal watershed, Washington, tension lysimeters and estimates of the soil water flux were used to quantify the mobilization and leaching of NO(3)-N, NH(4)-N, and dissolved organic nitrogen below the observed rooting depth. Soil and vegetation samples were collected before fertilization and 1 and 6 mo after fertilization. In the year after fertilization, the total leaching beyond the primary rooting zone in excess of control plots was 4.2 kg N ha(-1) (p = 0.03), which was equal to 2% of the total N applied. The peak NO(3)-N concentration that leached beyond the rooting zone of fertilized plots was 0.2 mg NO(3)-N L(-1). Six months after fertilization, 26% of the applied N was accounted for in the overstory, and 27% was accounted for in the O+A horizon of the soil. The results of this study indicate that forest fertilization can lead to small N leaching fluxes out of the primary rooting zone during the first year after urea application.     

GROUND WATER NITRATE REDUCTION IN GIANT CANE AND FOREST RIPARIAN BUFFER ZONES1

ABSTRACT: Ground water contamination by excess nitrate leaching in row‐crop fields is an important issue in intensive agricultural areas of the United States and abroad. Giant cane and forest riparian buffer zones were monitored to determine each cover type's ability to reduce ground water nitrate concentrations. Ground water was sampled at varying distances from the field edge to determine an effective width for maximum nitrate attenuation. Ground water samples were analyzed for nitrate concentrations as well as chloride concentrations, which were used as a conservative ion to assess dilution or concentration effects within the riparian zone. Significant nitrate reductions occurred in both the cane and the forest riparian buffer zones within the first 3.3 m, a relatively narrow width. In this first 3.3 m, the cane and forest buffer reduced ground water nitrate levels by 90 percent and 61 percent, respectively. Approximately 40 percent of the observed 99 percent nitrate reduction over the 10 m cane buffer could be attributed to dilution by upwelling ground water. Neither ground water dilution nor concentration was observed in the forest buffer. The ground water nitrate attenuation capabilities of the cane and forest riparian zones were not statistically different. During the spring, both plant assimilation and denitrification were probably important nitrate loss mechanisms, while in the summer nitrate was more likely lost via denitrification since the water table dropped below the rooting zone.     

Status and fuzzy comprehensive assessment of combined heavy metal and organo-chlorine pesticide pollution in the Taihu Lake region of China

The status of combined heavy metal and organo-chlorine pesticide (OCPs; i.e. HCH and DDT) pollution was investigated and the soil environmental quality of the Taihu Lake watershed, one of the most developed regions in China, was evaluated using a fuzzy comprehensive assessment. Statistical analyses showed the presence of combined pollution in the soil. At many sampling sites, heavy metal concentrations were above corresponding background values, indicating the effects of extraneous pollutants. It has been over 20 years since China banned the use of OCPs, but they can still be found in soil samples of this region. HCH levels at all investigated sites were below the Chinese Environmental Quality Standard for Soils. Fuzzy comprehensive assessment showed that the overall soil quality in this region could be categorized as class I. Nevertheless, the high coefficients of variation for levels of DDT, Cd and Hg indicated the existence of some point-source pollution. Continuous monitoring and further studies of the region are recommended to prevent pollution of farmland from these sources.     

梦清园芦苇湿地根际微生物特性研究

本文通过对上海市梦清园芦苇湿地净化苏州河污染水体的示范工程采样分析，结果表明芦苇根际的微生物数量、酶的活性高于非根际的土壤。根际细菌、真菌和放线菌的数量均比非根际多，R／S平均值分别为70．3、9．5、2．9。相对于硝酸细菌而言亚硝酸细菌的根际效应较为明显，无论根际还是非根际的亚硝酸细菌数量均高于硝酸细菌的数量。根际细菌和硝化细菌数量随着水力停留时间增加而增加，而根际反硝化细菌数量则减少。菌剂和酶制剂的加入使得非根际泥样异养细菌、真菌、放线菌和亚硝酸细菌比对照组稍高，硝酸细菌和反硝化细菌则较少；而根际泥样中加菌剂和酶制剂组微生物数量比空白组高出1—2个数量级，在投加菌和酶制剂后酶活性无论在根际还是非根际都得到提高，高于对照组约5—6个酶活单位。     

Transpiration and Root Development of Urban Trees in Structural Soil Stormwater Reservoirs

Stormwater management that relies on ecosystem processes, such as tree canopy interception and rhizosphere biology, can be difficult to achieve in built environments because urban land is costly and urban soil inhospitable to vegetation. Yet such systems offer a potentially valuable tool for achieving both sustainable urban forests and stormwater management. We evaluated tree water uptake and root distribution in a novel stormwater mitigation facility that integrates trees directly into detention reservoirs under pavement. The system relies on structural soils: highly porous engineered mixes designed to support tree root growth and pavement. To evaluate tree performance under the peculiar conditions of such a stormwater detention reservoir (i.e., periodically inundated), we grew green ash (Fraxinus pennsylvanica Marsh.) and swamp white oak (Quercus bicolor Willd.) in either CUSoil or a Carolina Stalite-based mix subjected to three simulated below-system infiltration rates for two growing seasons. Infiltration rate affected both transpiration and rooting depth. In a factorial experiment with ash, rooting depth always increased with infiltration rate for Stalite, but this relation was less consistent for CUSoil. Slow-drainage rates reduced transpiration and restricted rooting depth for both species and soils, and trunk growth was restricted for oak, which grew the most in moderate infiltration. Transpiration rates under slow infiltration were 55% (oak) and 70% (ash) of the most rapidly transpiring treatment (moderate for oak and rapid for ash). We conclude this system is feasible and provides another tool to address runoff that integrates the function of urban green spaces with other urban needs.     

Bermudagrass management in the Southern Piedmont USA: VI. Soil-profile inorganic nitrogen

Fate of applied N in forage-based agricultural systems is important to long-term production and environmental impacts. We evaluated the factorial combination of N fertilization targeted to supply 20 g N m 2 yr(-1) and harvest strategies on soil-profile inorganic N during the first 5 yr of 'Coastal' bermudagrass [Cynodon dactylon (L.) Pers.] management. Harvest strategy had much larger effects than fertilization strategy, most notably that soil-profile inorganic N was lower when hayed than under other systems. In the upper rooting zone (0- to 0.3-m depth), soil inorganic N (initially at 3.1 g m(-2)) remained unchanged during the 5 yr under unharvested and low and high grazing pressures (0.00 +/- 0.08 g m(-2) yr(-1)), but declined with haying (-0.25 g m(-2) yr(-1)). In the lower rooting zone (0.3- to 0.9-m depth), soil inorganic N (initially at 2.9 g m(-2)) accumulated with unharvested and low and high grazing pressure (0.64 +/- 0.20 g m(-2) yr(-1)), but remained unchanged with haying (-0.06 g m(-2) yr(-1)). Below the rooting zone (0.9- to 1.5-m depth), soil inorganic N (initially at 5.8 g m(-2)) increased with unharvested and high grazing pressure (0.34 +/- 0.03 g m(-2) yr(-1)), was unchanged with low grazing pressure (-0.10 g m(-2) yr(-1)), and declined with haying (-0.50 g m(-2) yr(-1)). Applied N appears to have been efficiently utilized by forage with subsequent sequestration into soil organic matter and little movement of inorganic N below the rooting zone (< 2% of applied N), irrespective of inorganic or organic fertilization strategy designed to supply sufficient N for high animal production from grazing.     

Nitrogen removal and nitrate leaching for two perennial,sod-based forage systems receiving dairy effluent

In northern Florida, year-round forage systems are used in dairy effluent sprayfields to reduce nitrate leaching. Our purpose was to quantify forage N removal and monitor nitrate N (NO3(-)-N) concentration below the rooting zone for two perennial, sod-based, triple-cropping systems over four 12-mo cycles (1996-2000). The soil is an excessively drained Kershaw sand (thermic, uncoated Typic Quartzip-samment). Effluent N rates were 500, 690, and 910 kg ha(-1) per cycle. Differences in N removal between a corn (Zea mays L.)-bermudagrass (Cynodon spp.)-rye (Secale cereale L.) system (CBR) and corn-perennial peanut (Arachis glabrata Benth.)-rye system (CPR) were primarily related to the performance of the perennial forages. Nitrogen removal of corn (125-170 kg ha(-1)) and rye (62-90 kg ha(-1)) was relatively stable between systems and among cycles. The greatest N removal was measured for CBR in the first cycle (408 kg ha(-1)), with the bermudagrass removing an average of 191 kg N ha(-1). In later cycles, N removal for bermudagrass declined because dry matter (DM) yield declined. Yield and N removal of perennial peanut increased over the four cycles. Nitrate N concentrations below the rooting zone were lower for CBR than CPR in the first two cycles, but differences were inconsistent in the latter two. The CBR system maintained low NO3(-)-N leaching in the first cycle when the bermudagrass was the most productive; however, it was not a sustainable system for long-term prevention of NO3(-)-N leaching due to declining bermudagrass yield in subsequent cycles. For CPR, effluent N rates > or = 500 kg ha(-1) yr(-1) have the potential to negatively affect ground water quality.     

Root growth and metal uptake in four grasses grown on zinc-contaminated soils

Depth and area of rooting are important to long-term survival of plants on metal-contaminated, steep-slope soils. We evaluated shoot and root growth and metal uptake of four cool-season grasses grown on a high-Zn soil in a greenhouse. A mixture of biosolids, fly ash, and burnt lime was placed either directly over a Zn-contaminated soil or over a clean, fine-grained topsoil and then the Zn-contaminated soil; the control was the clean topsoil. The grasses were 'Reliant' hard fescue (Festuca brevipila R. Tracey), 'Oahe' intermediate wheatgrass [Elytrigia intermedia (Host) Nevski subsp. intermedia], 'Ruebens' Canada bluegrass (Poa compressa L.), and 'K-31' tall fescue (Festuca arundinacea Schreb.). Root growth in the clean soil and biosolids corresponded to the characteristic rooting ability of each species, while rooting into the Zn-contaminated soil was related to the species' tolerance to Zn. While wheatgrass and tall fescue had the strongest root growth in the surface layers (0-5 cm) of clean soil or biosolids, wheatgrass roots were at least two times more dense than those of the other grasses in the second layer (5-27 cm) of Zn-contaminated soil. When grown over Zn-contaminated soil in the second layer, hard fescue (with 422 mg/kg Zn) was the only species not to have phytotoxic levels of Zn in shoots; tall fescue had the highest Zn uptake (1553 mg/kg). Thus, the best long-term survivors in high-Zn soils should be wheatgrass, due to its ability to root deeply into Zn-contaminated soils, and hard fescue, with its ability to effectively exclude toxic Zn uptake.