Cress Roots Research Articles

The effect of biochar obtained from waste filter coffee grounds on plant germination

Nowadays, coffee consumption is quite high, and the consumption of filter coffee is steadily increasing. Consequently, there is a significant increase in waste filter coffee. This study aims to evaluate waste filter coffee grounds using a zero-waste approach. In this context, the solid product of pyrolyzed waste filter coffee grounds was added to the soil in specific ratios to improve soil quality and increase yield. The effects on the root and stem development of arugula (Eruca vesicaria) and garden cress (Lepidium sativum) plants were investigated. Waste filter coffee grounds was homogeneously mixed with soil at application rates of 1, 2, and 4 tons/ha. The results of the study observed that the pyrolysis solid product positively affected plant growth. Comparing the data, the highest yield in plants was observed in soil with added biochar, while lower yields were seen in soil with added raw waste filter coffee grounds, and the lowest yield was found in soil without biochar. Among the soils with added biochar, the most significant root and stem development was observed in plants with 2 tons/ha of added biochar.

Allelopathic Activity of Annona reticulata L. Leaf Extracts and Identification of Three Allelopathic Compounds for the Development of Natural Herbicides

Using plant-based allelopathic compounds might be a potent substitute to help mitigate the effects of synthetic herbicides. Annona reticulata L. is often planted for its fruit in residential gardens. This plant is well-documented for its diverse ethnomedicinal uses. However, there is no information in the literature on the allelopathic potential of A. reticulata leaves. Therefore, the allelopathic potential and relevant allelopathic compounds of A. reticulata leaves were investigated in this study. The bioassays were carried out using a completely randomized experimental layout (CRD), and the resulting data were analyzed using one-way ANOVA at p ≤ 0.05. Aqueous methanol extracts of A. reticulata leaves significantly inhibited the growth of three dicots and three monocots (Lepidium sativum L., Medicago sativa L., Lactuca sativa L., Echinochloa crus-galli (L.) P. Beauv., Lolium multiflorum Lam., and Phleum pratense L., respectively). The level of growth inhibition was proportional to the A. reticulata extract concentration. Three compounds were purified through different chromatographic steps, and their structures were determined using spectroscopy and identified as loliolide, 5-hydroxy-3,4-dimethyl-5-pentylfuran-2(5H)-one, and 3,4-dihydroxyphenylethanol. The 5-hydroxy-3,4-dimethyl-5-pentylfuran-2(5H)-one had the greatest effect on suppressing cress root growth, while loliolide had the greatest effect on suppressing timothy shoot growth. The values for 50% seedling growth suppression showed that the compound with the maximum inhibitory activity was loliolide, followed by 5-hydroxy-3,4-dimethyl-5-pentylfuran-2(5H)-one and 3,4-dihydroxyphenylethanol. Therefore, this result suggests that the three compounds might be responsible for the allelopathic effects of A. reticulata leaf extracts, and these compounds have the potential to be used to develop effective bioherbicides.

The diversity of bacterial endophytes from Iris pseudacorus L. and their plant beneficial traits

This study reports the diversity of cultivable endophytic bacteria associated with yellow iris (Iris pseudacorus L.) by using 16S rRNA gene analysis and their plant beneficial traits. The 16S rRNA sequence similarities of endophytic bacteria isolated from the leaves and roots of yellow iris showed that the isolates belonged to the genera Staphylococcus, Streptomyces, Variovorax, Pantoea, Paenibacillus, Bacillus, Janthinobacterium, Enterobacter, Brevibacterium, Agrobacterium, Rhizobium, Xanthomonas translucens, and Pseudomonas. The endophytic bacteria Pseudomonas gessardii HRT18, Brevibacterium frigoritolerans HRT8, Streptomyces atratus HRT13, and Bacillus toyonensis HST13 exhibited antimicrobial activity against five plant pathogenic fungi Fusarium, Rhizoctonia, Botrytis, Pythium, and Alternaria. They also demonstrated the capability to produce chitinase, protease, glucanase, lipase, HCN, and indole-3-acetic acid (IAA). Thirteen isolates (46%) produced IAA, and the most active IAA producers were Bacillus cereus, Agrobacterium tumefaciens, Agrobacterium vitis, Bacillus megaterium, and Bacillus aryabhattai. The IAA producing bacterial isolates stimulated root and shoot growth of garden cress. Our findings suggest that medicinal plants could be a promising source for isolating plant-beneficial bacteria that can be used to enhance the growth and protect plants against soil-borne pathogens.

Assessment of allelopathic activity of Tradescantia spathacea Sw. for weed control.

Tradescantia spathacea Sw. (Commelinaceae) is widely cultivated as an ornamental and medicinal plant in Southeast Asia, and its pharmacological properties are well known. On the other hand, this plant species is classified as an invasive weed in some countries. As a noxious weed, T. spathacea has been reported to disrupt the growth of native plants. However, no study has reported on its allelopathic activity. Thus, we investigated the allelopathic property and inhibitory substance of T. spathacea. The extracts of T. spathacea significantly inhibited the shoots and roots of alfalfa (Medicago sativa L.), cress (Lepidium sativum L.), lettuce (Lactuca sativa L.), barnyard grass (Echinochloa crus-galli (L.) P. Beauv.), Italian ryegrass (Lolium multiflorum Lam.), and timothy (Phleum pratense L.) at concentrations ≥ 3mg dry weight (D.W.) equivalent extract/mL. As the extract concentration increased, the growth of the shoots and roots decreased. The I50 values of the test plant shoots and roots were 11.6-72.4 and 5.4-19.5mg D.W. equivalent extract/mL, respectively. The extracts were purified by column chromatography, and an inhibitory substance was separated, which inhibited the shoots and roots of cress to 18.8 and 11.6% of control growth, respectively. The results of present findings indicate that T. spathacea extracts possess an allelopathic property, and its inhibitory substance may contribute this activity.

Uptake and bio-transformation of telmisartan by cress (Lepidium sativum) from sewage treatment plant effluents using high-performance liquid chromatography/drift-tube ion-mobility quadrupole time-of-flight mass spectrometry

In the present study, the uptake and metabolization of the sartan drug telmisartan by a series of plants was investigated. Thereby for seven potential metabolites, modifications on the telmisartan molecule such as hydroxylation and/or glycosylation could be tentatively identified. For two additional signals detected at accurate masses m/z 777.3107 and m/z 793.3096, no suggestions for molecular formulas could be made. Further investigations employing garden cress (Lepidium sativum) as a model plant were conducted. This was done in order to develop an analytical method allowing the detection of these substances also under environmentally relevant conditions. For this reason, the knowledge achieved from treatment of the plants with rather high concentrations of the parent drug (10 mg L−1) was compared with results obtained when using solutions containing telmisartan in the μg - ng L−1 range. Thereby the parent drug and up to three tentative drug-related metabolites could still be detected. Finally cress was cultivated in water taken from a local waste water treatment plant effluent containing 90 ng L−1 of telmisartan and harvested and the cress roots were extracted. In this extract, next to the parent drug one major metabolite, namely telmisartan-glucose could be identified.

Allelopathic Potential and Active Substances from Wedelia Chinensis (Osbeck).

Wedelia chinensis (Asteraceae) is a wetland herb native to India, China, and Japan. It is a valuable medicinal plant recorded to have pharmaceutical properties. However, the phytotoxic potential of Wedelia chinensis has not yet been examined. Thus, we carried out this study to establish the allelopathic effects of Wedelia chinensis and to identify its phytotoxic substances. Extracts of Wedelia chinensis exhibited high inhibitory activity against the root and shoot growth of cress, alfalfa, rapeseed, lettuce, foxtail fescue, Italian ryegrass, timothy, and barnyard grass. The inhibition was varied with species and was dependent on concentrations. The extracts were separated through several purification steps, and the two effective substances were isolated and characterized as vanillic acid and gallic acid using spectral analysis. Vanillic acid and gallic acid significantly arrested the growth of cress and Italian ryegrass seedlings. The concentrations of vanillic acid and gallic acid needed for 50% inhibition (I50 values) of the seedling growth of the cress and Italian ryegrass were 0.04–15.4 and 0.45–6.6 mM, respectively. The findings suggest that vanillic acid and gallic acid may be required for the growth inhibitory activities of Wedelia chinensis.

Search for biologically active substances of natural origin based on low-polar conifer extracts

In recent years, research interest in the application of biologically active substances as a means of increasing the yield and stability of agricultural plants has been increasing. The main advantages of natural substances, which determines the prospects of their application in contemporary agricultural technologies, are seen in terms of their environmental safety and multifunctionality of action, including the ability to reduce various environmental stresses on plants. For both economic and ecological reasons, one of the main sources of biologically active substances consists of coniferous trees. Thus, an important task is presented in the search for new compounds from coniferous trees having growth-regulating and stress-protective properties as applied to various plants of commercial interest. In order to solve this problem, the growth-modulating and anti-stress biological activity of eight extracts containing compounds from needles and branches of three low-polar pine species (Pinus gen.) was tested using a model based on the Arabidopsis (thale cress) root and leaf rosette growth indicator. The obtained data confirmed the possibility of using the studied plant model for identifying the biological activity of low-polar metabolite extracts. Growth inhibition of the Arabidopsis main root, lateral roots and leaf rosettes by extracts and fractions of low-polar substances of the Pinus coniferous trees was demonstrated. The most significant growth inhibition of the main root was characteristic of the P. koraiensis (NIOC-28/1) needle hexane extract, while the neutral substances of the P. sibirica (NIOC-32/1) needle hexane extract suppressed the growth of both the main and accessory roots. The demonstrated allelopathic growth inhibition for Arabidopsis roots and leaf rosettes caused by extracts and fractions of low-polar substances of the Pinus coniferous trees shows the relevance of further study into the most active extracts for their possible application as herbicides. The absence of a positive effect for the studied extracts on the growth stability of the Arabidopsis root to heat shock was established.

Comparative analysis of agrochemical, allelopathic and microbiological characteristics of the soil environment for Actinidia arguta (Siebold et Zucc.) Planch. ex Miq. cultivated in Ukraine and two provinces of China

Objective – to evaluate agrochemical, allelopathic and microbiological characteristics of the soil environment for Actinidia arguta (Siebold et Zucc.) Planch. ex Miq. plants cultivated in Ukraine and two provinces of China.
 Material and methods. The rhizosphere soil was sampled at 0–15 cm layer under A. arguta plants in the stage of fruit ripening in Ukraine (Kyiv city: North of Ukraine, Forest-Steppe zone, a temperate continental climate) and two provinces of China (Shandong: East China, a monsoon temperate zone; and Heilongjiang: Northeast China, continental monsoon climate). The concentrations of carbon, available forms of macro- and micronutrients, phenolic compounds in the soil samples were determined. pH and redox potential of soil were measured. Soil phytotoxicity was studied by direct bioassay method on cress (Lepidium sativum L.) root growth. Microbiological analyses of soil samples were conducted.
 Results. The dissimilarities in the concentrations of carbon, macro- and micronutrients in the examined soil samples were shown. The domination of reduction conditions (Eh < 400 mV) in the soils under A. аrguta points the deceleration in the humification processes, as well as the presence of the mobile forms of organic compounds with the allelopathic properties. The redox potential decreased with the increase of pH values. This reflects the intensifying of reduction processes. The soil phytotoxicity under A. аrguta reached 20–70% compared with the control. This is obviously due to the accumulation of phenolic compounds as well as iron and manganese. The relationship between pH, the phytotoxicity and the abundance of the main taxonomical and ecological trophic groups of microbiota in soils under A. аrguta was ascertained.
 Conclusions. Calcic Luvisols from the M.M. Gryshko National Botanical Garden of the NAS of Ukraine (Kyiv city, Ukraine) and Luvic Chernozems from Jiamusi (Heilongjiang province, China) were determined to be the most favorable for A. arguta cultivation. Salic Solonetz from Harbin (Heilongjiang province, China) and Haplic Luvisols from Linyi (Shandong province, China) had the least suitable soil conditions for A. arguta plants.

THE INFLUENCE OF HUMIC ACIDS ON THE SOWING QUALITIES OF COCKWEED IN OIL POLLUTION

The stimulating effect of humic acids on the processes of growth and development of cress seeds has been revealed. It has been established that use of humic acids of black alder fen peat most effectively affects the sowing qualities of seeds under conditions of oil pollution (an increase in the germination energy and germination capacity compared to the non-humic acid variant by 38%). The minimal inhibitory effect on shoot growth was observed in the soil with hexadecane (20.8 mm less than the control), the maximum – in the soil with oil (22.5 mm less than the control). Humic acids show a stimulating effect on the growth of cress roots under conditions of pollution with oil hydrocarbons. The root length indicators exceeded the values obtained in the version with the pollutant without the use of humic acids from 6% (oil) to 16% of the control (hexadecane). Based on the data obtained during the vegetation experiments, it can be assumed that the stimulating activity of humic acids is more pronounced in stressful conditions for the organism. The biostimulating effect of humic acids was revealed, which manifested itself in an increase in the length of the hypocotyl and root, and the physiological activity of detoxicants was more effectively detected under conditions of pollution with oil hydrocarbons. According to the results of the vegetative experience on a substrate with hexadecane during the irrigation with humic acids of sphagnum high-moor peat, the maximum values of the test responses were determined, corresponding to the control values ​​obtained on the uncontaminated substrate, or higher than the latter. In the variant with oil, the most pronounced effect was achieved with the introduction of humic acids of reed fen and sphagnum high-moor peat, which confirms the hypothesis about the protective effect of humic acids in pollution conditions, which is determined by the binding ability of humic acids in relation to toxicant and their own biological activity in the relation to plants. It is proved that humic acids of peats make a significant contribution to the natural processes of self-purification, causing immobilization and detoxification of petroleum hydrocarbons, which indicates the prospects of their application in technologies of purification and recultivation of polluted water and soil media.

Garcienone, a Novel Compound Involved in Allelopathic Activity of Garcinia Xanthochymus Hook.

Plants are sources of diversified allelopathic substances that can be investigated for use in eco-friendly and efficient herbicides. An aqueous methanol extract from the leaves of Garcinia xanthochymus exhibited strong inhibitory activity against barnyard grass (Echinochloa crus-galli (L.) P. Beauv.), foxtail fescue (Vulpia myuros (L.) C.C.), alfalfa (Medicago sativa L.), and cress (Lepidium sativum L.), and appears to be a promising source of allelopathic substances. Hence, bio-activity guided purification of the extract through a series of column chromatography steps yielded a novel compound assigned as garcienone ((R, E)-5-hydroxy-5-((6S, 9S)-6-methyl-9-(prop-13-en-10-yl) tetrahydrofuran-6-yl) pent-3-en-2-one). Garcienone significantly inhibited the growth of cress at a concentration of 10 μM. The concentrations resulting in 50% growth inhibition (I50) of cress roots and shoots were 120.5 and 156.3 μM, respectively. This report is the first to isolate and identify garcienone and to determine its allelopathic potential.

Aged Acacia melanoxylon bark as an organic peat replacement in container media

The continuous search for peat substitution by local available organic materials, to reduce horticulture industry environmental foot-print, is growing worldwide. In Mediterranean region, Acacia melanoxylon bark is an abundant waste material from non-native tree species control actions, lacking suitable disposal. This study explores the potential use of A. melanoxylon bark as an alternative material for container media. Bark anatomy was characterized, the effect of different bark sieve sizes (4, 6, 8, and 10 mm) and the ageing treatment among successive periods of time (at 0, 4 and 8 weeks) were evaluated regarding substrate physical and chemical performance, as well as phytotoxic effect on tested seeds. Fresh bark was phytotoxic (cress root index < 22%) due to phenolic and extractives presence in bark material. Ageing bark during 8 weeks might eliminate those toxic elements which promoted cress roots growth equal to peat (root index > 99%). Ageing process may motivate Nitrogen immobilization which raises pH (up to 6.2) and dropped electrical conductivity (minimum of 14 mS m−1), however initial substrate amendment is required prior to potting, thus providing enough nutrients according to microbial-plant needs. Physical substrate performance was strongly correlated with particle size distribution: coarse bark (10 mm) increase air filled porosity, enhancing substrate aeration, while fine bark (4 mm) retain equal water content as commercial peat. Aged A. melanoxylon bark can be blended up to 50% with peat and produce plants as great as in commercial peat-based substrates.

Plant Growth Inhibitory Activity of the Extracts of Acmella oleracea and its Growth Inhibitory Substances

Aqueous methanol extracts of Acmella oleracea inhibited the growth of roots and shoots of cress ( Lepidum sativum), lettuce ( Lactuca sativa), Italian ryegrass ( Lolium multiflorum), and barnyard grass ( Echinochloa crus-galli) with the extract concentration-dependent manner. The extracts were then purified and 2 growth inhibitory substances were isolated and identified by spectral data as ( E,E)-2,4-undecadien-8,10-diynoic acid isobutylamide (compound 1) and nona-(2 Z)-en-6,8-diynoic acid 2-phenylethylamide (compound 2). Compound 1 inhibited the growth of cress roots and shoots at concentrations greater than 0.3 mM and that of barnyard grass root at concentrations greater than 0.03 mM. Compound 2 inhibited the growth of cress shoots and barnyard grass roots at concentrations greater than 1 mM. The inhibition on the seedling growth indicates that both compounds had growth inhibitory activity and may contribute to the inhibitory effect of A. oleracea extracts. This is the first report of having growth inhibitory activity of compounds 1 and 2 on plants.

(+)-Isoamericanol A: A Plant Growth Inhibitor From Heliotropium indicum

A plant growth inhibitory substance was isolated from Heliotropium indicum by bioassay-guided purification and characterized to be (+)-isoamericanol A. (+)-Isoamericanol A significantly inhibited seedling growth of cress at a concentration greater than 0.1 mM. The concentrations of (+)-isoamericanol A required for 50% growth inhibition of cress roots and hypocotyls were 0.5 and 0.4 mM, respectively. This inhibition indicates that (+)-isoamericanol A had a growth inhibitory activity and may contribute to the allelopathic effect of H. indicum. This report is the first on the plant growth inhibitory activity of (+)-isoamericanol A as an allelopathic substance.

Phytotoxic activity of Chinese violet (Asystasia gangetica (L.) T. Anderson) and two phytotoxic substances

Chinese violet (Asystasia gangetica (L.) T. Anderson) is a perennial invasive weed belonging to Acanthaceae. Leaves of this weed have been suggested to possess phytotoxic activity. However, phytotoxic substances in this weed have not yet been reported. Therefore, the present study investigated phytotoxic activity of Chinese violet extracts and phytotoxic substances. The extracts of Chinese violet leaves inhibited the root and shoot growth of cress, lettuce, alfalfa, barnyard grass, ryegrass, and timothy, where the level of inhibition increased with increasing extract concentrations. Bioassay‐guided separations of the extracts led to isolation of two phytotoxic substances, indole‐3‐carboxaldehyde and (6R,9S)‐3‐oxo‐α‐ionol. Indole‐3‐carboxaldehyde significantly inhibited the root and shoot growth of cress at concentrations ≥100 and 30 μmol L−1, respectively, and concentrations of the substance required for 50% growth inhibition were 210 and 127 μmol L−1 for cress roots and shoots, respectively. The other substance, (6R,9S)‐3‐oxo‐α‐ionol, was reported to have strongly inhibited cress roots and shoots. The present results suggest that Chinese violet contains two phytotoxic substances indole‐3‐carboxaldehyde and (6R,9S)‐3‐oxo‐α‐ionol, and those substances may play an important role in the phytotoxic activity of Chinese violet.

Identification of 6,7-Dimethoxychromone as a Potent Allelochemical from Jatropha podagrica

Jatropha podagrica Hook. is cultivated as an ornamental plant and is also used in traditional medicine. The species has various pharmacological properties, but it has not yet been investigated for any potential allelopathic activity and allelopathic substances. In this study, an allelopathic active substance was isolated from an aqueous methanol extract of J. podagrica leaves through chromatography and reverse-phase HPLC. The substance was characterized as 6,7-dimethoxychromone by spectral analysis. 6,7-Dimethoxychromone significantly inhibited the shoots and roots of cress at concentrations greater than 0.3 mM. The concentrations required of 6,7-dimethoxychromone for 50% growth inhibition of cress shoots and roots were 0.95 and 0.83 mM, respectively. The inhibitory activity against the seedling growth of cress indicates that 6,7-dimethoxychromone may contribute to the allelopathic effects and may be responsible for the allelopathic activity in J. podagrica. This report is the first on the allelopathic activity of 6,7-dimethoxychromone as an allelopathic substance from J. podagrica.

Isolation and identification of a phytotoxic substance in kiwifruit leaves

The yield of kiwifruit [Actinidia deliciosa (A. Chev.) C.F. Liang et A.R. Ferguson] often decreases after 20 years of cultivation. Replanted young kiwifruit plants cannot grow well in fields where aged trees were previously cultivated. Phytotoxicity is considered one possible reason for this problem. However, allelopathic or phytotoxic substances from kiwifruit have not been reported. This study aimed to isolate and identify potentially allelopathic active substances in kiwifruit leaves. Extracts from kiwifruit leaves inhibited the growth of cress, suggesting that kiwifruit leaf extracts may contain growth-inhibitory substances. The extracts were then purified using a silica-gel column, Sephadex LH-20 column, ODS cartridge, and HPLC. The inhibitory activity of all fractions obtained in each purification step was determined by the cress bioassay. Quercitrin was finally isolated and identified as a growth-inhibitory substance. This substance inhibited cress root growth by more than 50% of control at 3 mM. The aglycone of quercitrin, quercetin, did not significantly inhibit cress growth. Quercitrin may work as an allelopathic substance and cause the kiwifruit replant problem. Further study is in progress to investigate the influence of kiwifruit leaf extracts and these flavonoids on kiwifruit seedlings.

Plant growth inhibitory activity and active substances with allelopathic potential of cogongrass (Imperata cylindrica) rhizome

Cogongrass (Imperata cylindrica [L.] Raeusch.) is a perennial rhizomatous grass that belongs to the Poaceae and is widely distributed in tropical, subtropical and temperate regions over the world. The grass is strongly invasive and is suggested to have allelopathic potential. However, limited information is available on allelopathic substances in cogongrass rhizomes. Therefore, the allelopathic potential and substances in cogongrass rhizomes were investigated. The extracts of cogongrass rhizomes inhibited the root and shoot growth of barnyard grass, ryegrass, timothy, cress, lettuce and alfalfa. After bioassay‐guided separations of the extracts, four growth inhibitory substances, 5‐methoxyflavone, 5,2′‐dimethoxyflavone, methyl caffeate and abscisic acid, were isolated. 5‐Methoxyflavone, 5,2′‐dimethoxyflavone and methyl caffeate significantly inhibited the root and shoot growth of cress at concentrations of ≥0.03–0.3 m mol L−1 and their concentrations required for 50% growth inhibition were 0.079–0.24, 0.23–1.1 and 0.59–0.88 m mol L−1, respectively. The other isolated substance, abscisic acid, has been reported to have strong growth inhibitory activity. Its concentrations required for 50% growth inhibition on cress were 0.31–0.61 μ mol L−1. The present study suggests that cogongrass rhizomes might have allelopathic potential and that those four substances might contribute to that potential.

Two allelopathic substances from Paspalum commersonii Lam.

ABSTRACTPaspalum commersonii (Poaceae) is a herbaceous perennial weed distributed in the tropics and subtropics regions and grows mainly in the moist, or even flooded soil. It often appears in the rice field as a competitive weed and difficult to manage. Its strong competitive nature indicates possible allelopathic potential of P. commersonii. However, no studies have been found yet on the allelopathic activity of P. commersonii. Thus, we investigated the allelopathic potential of this weed and determined its allelopathic substances. Aqueous methanol extracts of P. commersonii showed concentration-dependent inhibitory activity on the seedling growth of cress, alfalfa, rapeseed, lettuce, barnyard grass, foxtail fescue, Italian ryegrass, and timothy. Two substances were isolated through bioassay-guided fractionation and their structures were determined through spectral data as dehydrovomifoliol and loliolide. Dehydrovomifoliol and loliolide started inhibiting the shoot and root growth of cress at concentrations greater than 3 and 0.03 mM, respectively. The concentrations required for 50% inhibition (I50) of cress shoot and root growth were 3.34 and >3.50 mM for dehydrovomifoliol and 0.04 and 0.05 mM for loliolide, respectively. These results indicate that both substances may affect the inhibitory activity of P. commersonii.

Preparation and phytotoxicity study of lappalone from dehydrocostuslactone

Lappalone, a sesquiterpene lactone isolated from the roots of Saussurea lappa, was successfully synthesized for the first time from dehydrocostuslactone following a four-step synthetic route, in which the first step was a photoaddition of acetaldehyde, with a global yield of 14%. The starting material, dehydrocostuslactone, was isolated in gram scale from Saussurea lappa root extracts. The phytotoxicity profiles of the product, the starting material and the intermediates were obtained in two different bioassays: on etiolated wheat coleoptiles and on seeds of Standard Target Species (STS). Low IC50 values were found for lappalone vs. dehydrocostuslactone (161μM and 839μM in cress roots, respectively), reaching 60–80% inhibition percentages at the highest concentrations. These bioassays indicated the higher potential allelopathic activity of the sesquiterpene lappalone (C17) when compared with dehydrocostuslactone (C15) and the intermediates in the synthetic route.

BIOLOGICAL ACTIVITY OF SECRETION OF PLANT MATTER AND SOIL FROM HYSSOP SPECIES (HYSSOPUS OFFICINALIS)

Hyssop (Hyssopus officinalis L.) comes from Mediterranean region. Cultural and wild forms grow in Europe, North America, and the Forest-Steppe and Steppe zones in the Eastern Europe. It is a perennial herbaceous semi-bush that ranges from 50 to 80 cm in height. In the study we performed experimental work on the basis of M.M. Gryshko National Botanical Garden of National Academy of Sciences of Ukraine (Kyiv city) and agrarian and biological station of Pavlo Tychyna Uman State Pedagogical University (Uman city, Cherkasy region). Allelopathic activity of water soluble (WSS), alcohol soluble (ASS) and volatile secretions (VS) was determined by biological tests (Hrodzynskyi, 1991) – one-day seedlings of garden cress (Lepidium sativum L.) in the model experiments. Comparative analysis of the activity of water soluble extracts of Hyssop showed that water soluble secretions from both above-ground organs and roots were characterized by high phytotoxicity recorded at the beginning of plant growth. Wheat coleoptiles were more tolerant to secreting; their activity was low in the condition of Kyiv city as well as Uman city. The authors have defined the following results regarding the reaction of winter wheat roots: secretions of all plant organs in the condition of Kyiv city were phytotoxic, but water soluble secretions from roots and stems had a stimulating effect and, on the contrary, secretions from leaves and inflorescences showed inhibitory impact in terms of Uman city. Most of plant ekzometabolites are accumulated in the soil of rhizosphere rhizoplan and contribute to its enrichment with organic compounds and mineral elements and also accumulation of humus. Received results showed dependence between accumulation of phytotoxic substances and soil type and climatic conditions. The conclusions are as follows. Different types of plant secretions of Hyssopus officinalis L. species during a vegetation period are analyzed. The largest number of substances with inhibitory action was localized in leaves and inflorescences. Blossoming phase was a demonstrative phase concerning allelopathic activity. Roots of garden cress were the most sensitive to secretions among selected test-objects. It was found that soil of rhizosphere and space between rows during a vegetation period accumulated colins, content of which depended on environmental factors and secretory functions of plants.