Allelopathic effect of <Emphasis Type="Italic">Nepeta meyeri</Emphasis> Benth. extracts on seed germination and seedling growth of some crop plants

In order to evaluate the allelopathic potential of Nepeta meyeri Benth., the effects of aqueous extracts (0.125, 0.25, 0.5, 1, 2.5 and 5%) prepared from roots and leaves of N. meyeri were studied on the seed germination and seedling growth of several economically important crops (barley, wheat, canola, safflower, and sunflower). Both the root and leaf extracts of N. meyeri caused a general phytotoxic effect on the seed germination and seedling growth of barley and sunflower at all concentrations. However, both the root and leaf extracts significantly increased the seedling growth of wheat, especially at the lower concentrations 0.125, 0.25 and 0.5%, whereas the higher concentrations had a neutral effect. The seed germination and the seedling growth of canola and safflower were also generally improved by both extracts, especially at lower concentrations. However, these advantages were not observed at higher concentrations, at which the extracts mostly had a phytotoxic effect on canola and safflower. The Allelopathic activity of N. meyeri depended on whether the extract was derived from the leaf or root parts of the plant. The maximum allelopathic effect occurred with leaf extracts. The results demonstrate that the aqueous extracts from N. meyeri have allelopathic potential and should be evaluated as an allelopathic species, presenting a risk or advantage to seed germination and seedling growth of crop or weed plants.     

冷蒿对三种禾本科植物种子萌发和幼苗生长的化感作用

研究了冷蒿茎叶水浸提液及冷蒿斑块土壤对羊草草原3种禾本科植物(羊草、克氏针茅和糙隐子草)种子萌发及幼苗生长的影响.结果表明:冷蒿茎叶水浸提液使受试植物种子的发芽指数降低,平均发芽时间延长.羊草、克氏针茅和糙隐子草幼苗苗高及克氏针茅幼苗根长均受冷蒿茎叶水浸提液抑制;浸提液浓度≥0.075g.ml-1时显著抑制羊草幼苗根长生长,≤0.05g.ml-1时则无显著影响;而茎叶水浸提液对糙隐子草幼苗根长有"低促高抑"的作用.冷蒿斑块土壤抑制受试植物幼苗生长;3种植物对冷蒿化感效应的敏感性依次为克氏针茅羊草糙隐子草,且幼苗根长的敏感性均大于苗高.     

Biological control of the wheat root rot caused by Fusarium graminearum using some PGPR strains in Saudi Arabia

The aim of this study was to evaluate the efficacy of selected bacterial strains against the wheat soil‐borne pathogen Fusarium graminearum under greenhouse conditions. The most potent isolates were 3 isolates out of 18 isolates, which have numbers 3, 9 and 10 with in vitro inhibition index 42.5%, 41.3% and 46.3% respectively. Isolates 3 and 10 were selected for the following experiments. Isolates 3 and 10 were identified as Bacillus subtilis MAA03 and Pseudomonas fluorescens MAA10, respectively according to International Identification Keys and, confirmed by using Biolog system and 16S rDNA where the strains exhibited more than 99.5% sequence identity. Their close taxonomic relationship was further documented by phenotypic similarities. The using of B. subtilis and P. fluorescens separately or in mixture as biocontrol agent against F. graminearum on wheat significantly increased the final germination percent, the mean daily germination and germination index of wheat cultivar, while the mean germination time was significantly decreased relative to infested control. The final infection percent, the mean daily infection and infection index were decreased significantly, while the mean infection time was significantly increased relative to infested control. The use of P. fluorescens as biocontrol agent was the most efficient than B. subtilis or in mixture and the best treatment was seed coating. The application of B. subtilis and P. fluorescens separately or in combination significantly affected the growth parameters of wheat cultivar Tabuki, the root length was significantly increased in seed coating and seed soaking treatments, while non‐significantly decreased in case of soil drench treatment relative to infested control. Shoot length was significantly decreased in case of seed coating treatment relative to infested control. The shoot fresh and dry weights were significantly increased in seed coating and seed soaking treatments relative to infested control. The root fresh and dry weights were significantly increased in seed coating and seed soaking treatments relative to infested control. The number of leaves was significantly increased in all treatments relative to infested control.     

黄土丘陵区草本群落演替中先锋种群茵陈蒿浸提液的化感作用

为探索自然演替中植被群落结构与化感作用之间的关系,以黄土丘陵区自然演替中先锋种群茵陈蒿为研究对象,通过种子萌发试验,分析演替初期优势种群茵陈蒿浸提液(甲醇浸提液和水浸提液)对自身以及伴生种种子萌发以及幼苗生长的影响,从化学生态学角度解释演替初期群落结构形成的原因。结果表明,茵陈蒿浸提液对3种伴生种(铁杆蒿、白羊草和达乌里胡枝子)的种子萌发均有显著化感作用,低浓度(0.002g/m L)时表现为促进或轻微的抑制作用,高浓度(0.2g/m L)时为较强的抑制作用;不同部位茵陈蒿浸提液的化感作用不同,相比之下,地上部的抑制作用更为强烈,其浸提液均抑制铁杆蒿、白羊草和达乌里胡枝子的种子萌发,尤其在浓度为0.2 g/m L时,达到完全抑制;根系甲醇浸提液对铁杆蒿种子萌发的抑制作用要强于同浓度下的水浸提液,而地上部水浸提液对受体植物根芽的作用大于甲醇浸提液。茵陈蒿对于自身具有一定的抑制作用,表现为高浓度(0.2和0.02 g/m L)的水和甲醇浸提液抑制自身种子萌发和幼苗生长。研究结果说明化感作用可能是该地区在演替前期形成以茵陈蒿为优势种植被群落的重要原因之一。创新点:从化学生态学的角度解释了黄土丘陵区植被演替初期植物之间的关系以及群落结构形成的原因,为认识自然恢复的内在机理提供了新的视角。     

Differential belowground allelopathic effects of leaf and root of Mikania micrantha

This study evaluates the relative contributions of leaves and roots to the belowground allelopathic effects of Mikania micrantha. The hypothesis that leaves contribute more to the allelopathic effect than roots was experimentally tested. We assessed the allelopathic effects of aqueous extracts from Mikania leaves and roots on the seed germination and seedling growth of two co-occurring woody plants in southern China, Lagerstroemia indica L. and Robinia pseudoacacia L. The results showed that the aqueous extracts from Mikania leaves and roots had inhibitory effects on the woody species. Allelopathic activity depended on the concentration of the extracts, target species, and the extract sources (i.e., leaves vs. roots of Mikania). Leaf extract showed stronger allelopathic effects than root extract on germination percentage, initial germination time, speed of germination, and shoot height; while root extract had greater allelopathic effects on roots than leaf extract. The latter phenomenon might greatly promote the invasion success of Mikania due to more direct and effective allelopathy of root. Our results suggest that allelopathy of root extract on belowground biomass might be greater than that of leaf extract for some species in contrast allelopathy of leaf extract on belowground biomass might also be greater than that of root extract for other species, at least for their effects on root growth of the target species.     

白桦、落叶松不同器官水浸液对种子萌发和播种苗生长的种间化感作用

研究了白桦的根、枝、叶,落叶松的根、枝、叶和皮不同浓度水浸液(5.0、12.5、25.0、50.0和100.0 mg·mL-1)对另一树种种子萌发和当年生播种苗生长的化感作用.结果表明:落叶松不同器官水浸液(根5.0 mg·mL-1除外)处理均抑制白桦种子的萌发,其平均发芽率为:对照(75％)＞根(66％)＞皮(59％)＞枝(58％)＞叶(54％),随浓度增加,根、枝水浸液的抑制作用增强,而叶、皮水浸液的抑制作用减弱.落叶松各器官水浸液对白桦胚根和胚轴生长具有较强的抑制作用,且以100.0 mg·mL-1浓度的叶水浸液抑制作用最强,胚根和胚轴长分别降低38％和55％(P＜0.05).落叶松枝、叶水浸液处理对白桦播种苗的苗高、地径及生物量有一定的促进作用,根、皮水浸液则具有抑制作用.白桦各器官水浸液能促进落叶松种子的萌发,根和枝的水浸液促进胚轴生长,叶的水浸液抑制胚轴生长,50.0和100.0 mg·mL-1浓度的叶水浸液处理的种子胚轴分别较对照降低27％和28％(P＜0.05).其对落叶松播种苗生长的影响以促进作用为主,5.0 mg·mL-1浓度的白桦叶水浸液处理的落叶松苗高、地径、生物量分别较对照高54％、60％和100％ (P＜0.05).白桦与落叶松之间存在明显的化感作用,混交可能对林木生长产生一定的促进作用.     

紫茎泽兰提取物对3种杂草的化感胁迫作用

为探讨紫茎泽兰(Eupatorium adenophorum)提取物对植物种子萌发和早期幼苗生长的影响及其生理机理,以稗草(Echinochloa crusgalli)、灰绿藜(Chenopodium glaucum)和反枝苋(Amaranthus retroflexus)3种常见的田间杂草为材料,采用根悬空培养等方法,研究了不同浓度紫茎泽兰提取物对3种杂草种子萌发和幼苗生长、根尖组织结构、根系边缘细胞(root border cell,RBC)生理特性和根冠果胶甲基酯酶(pectin methyl esterase,PME)活性的影响。结果发现:紫茎泽兰提取物对3种植物种子萌发均具有明显的抑制作用;1000 mg/L紫茎泽兰提取物处理后,3种杂草幼苗的根尖均有不同程度的伤害,如根尖肿胀、抽缩或变形;根尖表层细胞脱落、内层细胞排列混乱。紫茎泽兰提取物处理能显著抑制3种杂草幼苗根尖RBC的数量(分别比对照降低了44.5%、48.3%和64.0%);诱导RBC凋亡(凋亡率分别达到81.7%、91.3%和97.1%)并显著增加RBC的黏胶层厚度(分别比对照增加了99.0%、65.5%和61.1%)及诱导PME活性升高。这些结果表明:紫茎泽兰提取物抑制了3种杂草根边缘细胞的产生,并诱导了根尖边缘细胞凋亡,因而破坏了根边缘细胞对根尖的保护系统,最终抑制了根系的生长发育。研究为将紫茎泽兰提取物用于植物源除草剂的开发提供了理论依据。     

Allelopathic Potential and Mechanism of Rosebay Willowherb [<i>Chamaenerion angustifolium</i> (L.) Scop.] Demonstrated on Model Plant Lettuce

Allelopathic plants are important resources for the discovery of bioherbicides. Rosebay willowherb [Chamaenerion angustifolium (L.) Scop. syn. Epilobium angustifolium L.] widely distributes in Western Asia, Europe, and North America, and behaves as a dominant species within the community due to the production of substances that restrict growth of other plants. This study aims at investigating the allelopathic potential of rosebay willowherb by evaluation of the effects of aqueous extracts from different parts on seed germination and seedling growth in lettuce (Lactuca sativa L.), as well as measuring the accumulation of reactive oxygen species and structural analysis of root tips via scanning electron and transmission electron microscopy. It was observed that the aqueous extracts from the leaves of rosebay willowherb had the strongest inhibitory effect on the germination index, germination energy and total germination of lettuce seeds, followed by capsular fruits and flowers, and the inhibition effect of stems was the weakest. All aqueous extracts (100 mg/mL) showed a significant inhibitory effect on radicle elongation of lettuce seedlings. Additionally, after treatment with the aqueous extract of rosebay willowherb leaves, accumulation of reactive oxygen species increased in columella cells, which correlated with disruption of root tip structure.     

Effects of Biological Soil Crusts on Seed Bank, Germination and Establishment of Two Annual Plant Species in the Tengger Desert (N China)

The presence of biological soil crusts can affect the germination and survival of vascular plants, but the reasons are not well investigated. We have conducted a field investigation and greenhouse experiments to test the effect of crusts on two desert annual plants, which occur on the stabilized dunes of the Tengger Desert in N China. The results showed that biological soil crusts negatively influenced the seed bank of Eragrostis poaeoides and Bassia dasyphylla. The important effect of biological soil crusts on seed germination and establishment were performed indirectly through reducing the amount of germinating seeds. Field investigation and experimental results with regard to the seed bank indicated that higher seedling density was found in disturbed crust soil and bare soil surface than in intact crust soils. Greenhouse experiments showed that the effects of biological soil crusts on germination and establishment of the two plants are not obvious in moist condition, while disturbed crusts are more favorable to seed germination in dry treatment. Significant differences in biomass were found between disturbed crust soil and bare soil. Survival and growth of the two annual plants were enhanced in both algal and moss crusts during the season of rainfall or in moist environment, but crusts did not affect seedling survival in the dry period. The small seeded E. poaeoides has higher germination than larger-seeded B. dasyphylla in crust soils, but B. dasyphylla has a relatively higher survival rate than E. poaeoides in crust soils.     

Studies in the ecology of coastal heath in New South Wales

Effects of heating dry seed were investigated in Banksia serratifolia and B. ericifolia. Seeds were inviable after 7 min exposure at 150°C or higher temperatures but remained viable after exposure at 100°C and lower temperatures. Imbibed seeds show no dormancy, and seeds survive fire insulated from heat in the thick woody follicles which may persist unopened for several years on the parent plant but open following fire. Effects of nutritional supplements were observed in the seed germination and seedling survival and growth of Banksia serratifolia, B. aspleniifolia and B. ericifolia. Germination with radicle and hypocotyls extension was not significantly affected by a wide range of mineral nutrient regimes. In pot experiments using a heath soil seedling survival and growth were adversely affected by moderate additions of phosphate with surviving seedlings showing toxicity symptoms and poor development of proteoid roots. Moderate supplements of potassium had no adverse effect, and in B. serratifolia and B. ericifolia lessened the adverse effects of phosphate addition. The slow growth of the seedlings accords with the normal low nutrient availability in heath soils but seedlings show little capacity for rapid exploitation of any temporary increase of available nutrients after fire.     

侧柏不同器官水提取物对油松种子萌发和幼苗生长的他感效应

研究了侧柏（Platycladus orientalis）根、枝、叶、果实不同浓度水提取物及枝叶挥发油对油松种子萌发和幼苗生长的他感效应。结果表明：侧柏各器官及挥发油都含有化感物质,均对油松种子萌发及幼苗生长表现出“高抑低促”效应,而且低浓度时的促进作用明显强于高浓度时的抑制作用。与对照相比,在浓度为2 mg·mL^-1时,侧柏根水提取物对油松幼苗根长和鲜重的促进能力最强,其根长和鲜重分别比对照提高了79.78%和376.60%;侧柏叶水提取物对油松幼苗苗高促进能力最强,比对照提高了102.41%;侧柏枝水提取物对油松种子发芽的促进能力最强,发芽率比对照提高了65.63%。而在浓度为30 mg·mL^-1时,除了侧柏根和枝水提取物对油松种子萌发（87.50%）和鲜重（85.11%）表现出明显的抑制作用外,其它提取物对油松幼苗根长和苗高生长的抑制作用均不明显。侧柏枝叶挥发油对油松种子萌发,幼苗生长均表现为促进作用,特别对油松种子萌发具有显著的促进作用,其促进率达70.37%。说明侧柏和油松混交,可能有利于油松树木生长及生产力的提高。     

沙蒿(Artemisia ordosica)水浸提液对4种伴生草本植物的化感作用

以生长在我国荒漠和半荒漠地区的特有植物沙蒿为供体植物,沙米、虫实、草木樨状黄芪、狗尾草为受体植物,研究了沙蒿根、茎、叶、种子水浸提液对受体植物种子发芽、幼苗生长以及根对NH~+_4和K~+吸收的化感效应的差异,为沙区植被恢复中伴生杂草种类的选择提供理论依据。结果表明:沙蒿水浸提液对4种受体植物种子发芽和幼苗生长均具有显著的化感效应,沙米、虫实、草木樨状黄芪表现为抑制作用,狗尾草表现为促进作用。不同部位沙蒿浸提液的化感作用不同,根浸提液对沙米、虫实、狗尾草的化感效应最强,茎浸提液对草木樨状黄芪的抑制最强。不同植物种及植物的不同发育时期对化感作用的敏感性也不同,在4种受体植物中,沙米受抑制最强,其次为虫实、草木樨状黄芪,且随浸提液浓度增加而显著增强,而狗尾草具有一定的耐受力,表现为促进作用。沙蒿浸提液对受体植物根长的影响最强,其次是种子发芽、苗高和幼苗干质量。浸提液显著降低沙米、虫实、草木樨状黄芪根对NH~+_4和K~+的吸收,增加狗尾草根对NH~+_4和K~+的吸收。研究结果表明雨水淋溶是沙蒿向环境中释放化感物质的途径之一,化感作用在增强沙蒿生存竞争力,扩大种群过程中起着不容忽视的作用,可能是沙蒿单优势种群落形成的原因之一。     

铁核桃根与叶水浸提液对果园间作绿肥植物的化感作用及其生理机制

以西南地区具有代表性的16种绿肥植物为受体材料,采用培养皿药膜法研究了铁核桃(Juglans sigillata)根水浸提液对受体种子发芽率及幼苗鲜重、干重的化感效应;并进一步研究了铁核桃根、叶水浸提液和胡桃醌对化感效应存在明显差异的4种绿肥植物(绿豆、红三叶、白三叶、花生)种子萌发与幼苗生长以及抗氧化酶特性的影响,以筛选适宜中国西南地区核桃园种植的绿肥植物,探讨核桃根和凋落物对绿肥作物的化感作用机制。结果表明:(1)铁核桃根水浸提液对绿豆的发芽率没有影响,但对绿豆幼苗鲜重和干重有显著抑制作用,而对其他15种绿肥的发芽率和鲜重、干重均有抑制作用。(2)胡桃醌显著抑制绿豆种子萌发,而铁核桃根或叶水浸提液对绿豆种子萌发没有影响。(3)铁核桃根或叶水浸提液以及胡桃醌对绿肥植物幼苗生长的化感效应趋势一致,但核桃根或叶水浸提液的化感效应强于胡桃醌。(4)绿豆幼苗在铁核桃根或叶水浸提液以及胡桃醌处理下,超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)的活性均高于其他3种(红三叶、白三叶、花生)受体幼苗,表明绿豆清除活性氧能力高,细胞受损害程度较低,受化感作用影响最弱。研究认为,绿豆为适宜中国西南地区幼龄核桃园种植的间作绿肥植物。     

Effects of exogenous polyamines and difluoromethylornithine on seed germination and root growth of Arabidopsis thaliana

Effects of exogenous polyamines and difluoromethylornithine (DFMO) on seed germination and seedling root growth of Arabidopsis thaliana were investigated. Root growth was stimulated by low concentrations of putrescine but was increasingly inhibited by high concentrations of putrscine. DFMO inhibited root growth and this inhibition was reversed by applying putrescine. In contrast, both spermidine and spermine had no effect on root growth but inhibited seed germination. The results suggest a possible requirement of endogeneous putrescine for normal root growth of Arabidopsis seedlings.Abbreviations DFMO difluoromethylornithine - DFMA difluoromethylarginine - ODC ornithine decarboxylase - Put Putrescine - Spd Spermidine - Spm Spermine     

Salinity and salt composition effects on seed germination and root length of four sugar beet cultivars

Salinization is one of the most important factors affecting agricultural land in the world. Salinization occurs naturally in arid and semiarid regions where evaporation is higher than rainfall. Sugar beet yield declines with an increase in salinity, but the sensitivity to salts varies with salt composition in water and sugar beet growth stage. The aim of this study was to determine the effect of water salinity levels and salt composition on germination and seedling root length of four sugar beet cultivars (PP22, IC2, PP36, and 7233). The experiments were undertaken with irrigation water with two salt compositions (NaCl alone and mixture of MgSO₄ + NaCl + Na₂SO₄ + CaCl₂) in three replicates. Thirteen salinity levels with electrical conductivity (EC) of the irrigation water ranging from 0 to 30 dS/m were applied to each cultivar in both experiments. Seed germination percentage and seedling root length growth were determined in 13 days. Statistical analysis revealed that germination and root length were significantly affected by salt composition, cultivars and salinity levels. Regardless of salt composition, seed germination and seedling root length were significantly affected by the irrigation water with EC up to 8 dS/m and 4 dS/m, respectively. Except for cultivar PP22, the adverse effect of salinity of the irrigation water on seed germination and seedling root length was higher for NaCl alone than for the salt mixture, which refers to lower salt stress in field conditions with natural salt composition. Presented at the International Conference on Bioclimatology and Natural Hazards, Poľana nad Detvou, Slovakia, 17–20 September 2007.     

落叶松水浸液对胡桃楸种子萌发和幼苗生长的影响

研究了落叶松水浸液对胡桃楸种子萌发和幼苗生长的影响.结果表明,与对照相比,25 g ·kg^-1浓度的落叶松根水浸液,125 g·kg^-1浓度的落叶松皮、枝水浸液对胡桃楸种子发芽率、发芽指数均表现出显著的促进作用（P＜0.05）;12.5 g·kg^-1和25 g·kg^-1浓度的落叶松根水浸液、12.5 g·kg^-1浓度的落叶松皮水浸液对胡桃楸幼苗苗高、地径生长的促进作用显著（P＜0.05）.高浓度的落叶松叶水浸液对胡桃楸种子萌发和幼苗生长具有明显的促进作用（P＜0.05）.而落叶松叶水浸液对胡桃楸种子发芽率、发芽指数、苗高以及地径的促进作用却随着水浸液浓度的降低,呈逐渐下降的趋势.施加落叶松水浸液对胡桃楸种子萌发以及幼苗生长的促进作用可能与树种间的化学相互作用有关.     

岩生植物金发草对作物的化感效应

采用生物测定法研究金发草根、茎、叶水浸提液对水稻、小麦、油菜和莴苣等4种受体植物的化感作用。结果表明,金发草根、茎、叶水浸提液对4种受体植物种子萌发和幼苗生长均具化感作用,且随着水浸提液浓度的增高而增强。除水稻外,小麦、油菜、莴苣的发芽速率均受金发草水浸提液的显著抑制,但对最终发芽率影响不显著,说明金发草对植物种子萌发的化感作用主要是延迟种子发芽时间;金发草对作物幼苗生长的化感作用总体上表现为促进地上部分生长而抑制地下部分的生长。受体植物不同发育期对金发草化感作用的敏感程度不同,幼苗期高于萌发期;金发草叶的化感作用最强,其综合效应分别为根与茎的2.14倍和2.56倍。     

Inhibition of Seed Germination and Root Development Caused by Xanthomonas campestris pv. vesicatoria in Pepper and Tomato

Inoculation of pepper seeds with the leaf pathogen Xanthomonas campestris pv. vesicatoria inhibited pepper germination. The inhibitory effect, which was stronger in non-sterilized light textured soils, decreased with time, and after 20, days or more, there was no difference between inoculated and non-inoculated seeds. Inhibitory substance(s) within the cytoplasmatic fraction of pathogen cells inhibited the germination of non-host tomato seeds. No relationship between pathogenicity to pepper leaves and inhibition of pepper seed germination was detected. The inhibitory substance(s) was found in two out of four X. campestris pv. vesicatoria strains. Heat-killed bacteria suppressed growth of pepper but not tomato seedlings. It is, therefore, suggested that the inhibition of seed germination and the decrease in root development are different modes of X. campestris pv. vesicatoria pathogenesis toward pepper plants.     

Influence of fungal isolates on germination and growth of perennial ryegrass

Summary The influence of fungi isolated from perennial ryegrass roots on the germination and development of seedlings of perennial ryegrass was investigated. The basic procedure employed was to sterilise the seed surface and then inoculate with fungi and plant in non-sterile soil. It was realised that the fungal isolate inoculated on to the sterile seed surface would not remain dominant in the root region of the host and would have an influence on the host which would decline with time from when the seed germinated. This was because it would have to face antagonism from the normal components of the root microflora present in the non-sterile soil.Trichoderma viride delayed the emergence of the seedlings and reduced the production of herbage, an observation consistent with results of some other investigators. A sterile hyaline fungus stimulated the emergence of the seedlings, but subsequent tests showed that the presence of the microflora of the seed coat, or the soil microflora, or the sterile hyaline fungus was effective in promoting the rate of germination of seed that had been surface sterilised. Leaching seed in water brought about an increase in the rate of seed germination, and it is suggested that there might be a germination inhibitor soluble in water present in the seed coat, which might be inactivated by saprophytic micro-organisms.     

Influence of Phenol and Phenanthrene on the Growth of Phalaris arundinacea and Phragmites australis

In constructed wetlands for the treatment of industrial effluents and in contaminated waterlogged soils, wetland plants (helophytes) are exposed to toxic chemicals. Hence, the plants' resistance to contaminants is an important prerequisite for applying phytoremediation to solve these environmental problems. For toxicity tests on the germination and growth of various helophytes (Phalaris arundinaceae and Phragmites australis), phenol, phenanthrene, and a mixture of both were used as examples of chemicals from the petrol- and coal-processing industries. The germination rate, shoot length, root length, and influence on leaves, young shoots, and dry weight were studied. Although an increase in contaminant concentration decreased plant growth (dry weight, shoot length); interestingly, the number of young shoots rose. Low contaminant concentration (about 50 mg/l in case of phenol) stimulated the plant growth. The cress seed germination test was less susceptible compared with plantlet exposure in the case of phenol and phenanthrene. Due to its low bioavailability, solid phenanthrene (without solutizer) did not significantly affect plant growth.