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The aim of this study was to evaluate the most abundant native plants that could be used as a bio-monitor of metal(loid) concentration in dry riverbeds affected by mining activities. Three plants species and their respective rhizospheric soils were sampled from the El Beal (Piptatherum miliaceum, 15 samples), La Carrasquilla (Foeniculum vulgare, 10 samples), and Ponce (Dittrichia viscosa, 12 samples) dry riverbeds from the mining district of Cartegena-La Unión (SE Spain). There is scanty bibliography of the capacity of these species to be used as bio-monitors in the dry riverbeds. Plants categorized as a bio-monitor were established according to the bioaccumulation factor (BF), mobility ratio (MR), and linear correlations between metal(loid) concentrations in plants tissues (root or stem)-rhizospheric soils. The rhizospheric soils were highly contaminated for As, Cd, Pb, and Zn (Cf ≥ 6), and moderately contaminated for Mn (1 ≤ Cf < 3). Piptatherum miliaceum presented on Cd similar mean concentrations on rhizospheric soil and root, BF = 1.07, with a strong correlation soil–root (r = 0.61, p = 0.02). Therefore, of the three species with the capacity to grow in the area, Piptatherum miliaceum showed characteristics to be considered as a bio-monitor for Cd, with a BF > 1, and a positive–significant correlation between the rhizospheric soil and roots.

The current review was aimed at investigating the potential of Lantana camara extract as an effective alternative for synthetic herbicides to control weeds and also establishing the effects of allelochemicals in the extract on the germination and growth of cultivated crops. The researchers assessed abstracts and articles published from 2011 to 2022. The review has established that although L. camara extract has allelopathic properties to suppress the germination and growth of weeds in the fields. However, the extract is not entirely selective for the plants it inhibits; as a result, it also suppresses the growth of cultivated crops. Therefore, the review recommends that the extract should only be used on crops whose germination and growth cannot be suppressed by it. There is a need to establish the proper timing of the application of the extract to avoid the suppression of germination and early seedling growth in cultivated crops. More studies have been done on the effects of extract on plants in the Poaceae, Fabaceae, and Brassicaceae families. Therefore, more research has to be done to evaluate the allelopathic effects of L. camara extract on agronomic crops under Onagraceae , Solanaceae, Asteraceae, Convolvulaceae, Euphorbiaceae, Malvaceae, and Amaranthaceae families.There is limited information on the effects of the L. camara extract on the yields of the crops; as such, this review recommends that further research be conducted to evaluate the effects of the allelochemicals of L. camara on the yields of the cultivated crops in the fields where the extract has been applied.

Even today, weeds continue to be a considerable problem for agriculture. The application of synthetic herbicides produces serious environmental consequences, and crops suffer loss of their activity due to the appearance of new resistant weed biotypes. Our aim is to develop new effective natural herbicides that improve the problem of resistance and do not harm the environment. This work is focused on a bioassay-guided isolation and the characterization of natural products present in Moquiniastrum pulchrum leaves with phytotoxic activity and its preliminary application in weeds. Moquiniastrum pulchrum was selected for two reasons: it is an abundant species in the Cerrado region (the second most important ecosystem in Brazil, after the Amazon)-the explanation behind its being a dominant species is a major focus of interest-and it has traditional employment in folk medicine. Six major compounds were isolated in this plant: one flavone and five diterpenes, two of which are described for the first time in the literature. Four of the six compounds exhibited phytotoxic activity in the bioassays performed. The results confirmed the phytotoxic potential of this plant, which had not been investigated until now.

In the search of new alternatives for weed control, spices appear as an option with great potential. They are rich in bioactive natural products and edible, which might minimize toxicity hazard. Marjoram (Origanum majorana L.) is an aromatic herb that has been widely employed as a seasoning herb in Mediterranean countries. Although marjoram boasts a plethora of therapeutic properties (painkiller, antibiotic, treatment for intestinal disorders, etc.), the potential for its extracts for weed control is still to be more thoroughly explored. In order to determine their phytotoxic potential, marjoram leaves were subjected to different bioguided extraction processes, using water, ethyl acetate, acetone or methanol. The most active extract (acetone) was sequentially fractionated to identify its most active compounds. This fractionation led to the isolation and identification of 25 compounds that were classified as monoterpenes, diterpenes or flavonoids. Among them, a new compound named majoradiol and several compounds are described in marjoram for the first time. The phytotoxicity of the major compounds to etiolated wheat coleoptiles was compared against that of the commercial herbicide (Logran(R)), with similar or higher activity in some cases. These results confirm the extraordinary potential of the extracts from this edible plant to develop safer and more environmentally friendly herbicides.

Coumarin is a phytotoxic natural compound able to affect plant growth and development. Previous studies have demonstrated that this molecule at low concentrations (100 µM) can reduce primary root growth and stimulate lateral root formation, suggesting an auxin-like activity. In the present study, we evaluated coumarin’s effects (used at lateral root-stimulating concentrations) on the root apical meristem and polar auxin transport to identify its potential mode of action through a confocal microscopy approach. To achieve this goal, we used several Arabidopsis thaliana GFP transgenic lines (for polar auxin transport evaluation), immunolabeling techniques (for imaging cortical microtubules), and GC-MS analysis (for auxin quantification). The results highlighted that coumarin induced cyclin B accumulation, which altered the microtubule cortical array organization and, consequently, the root apical meristem architecture. Such alterations reduced the basipetal transport of auxin to the apical root apical meristem, inducing its accumulation in the maturation zone and stimulating lateral root formation.

Given the importance of the genus Artemisia as a source of valuable natural products, the rare plant Artemisia pedemontana subspecies assoana, endemic to the Iberian Peninsula, has been experimentally cultivated in the greenhouse and aeroponically, to produce biomass for essential oil (EO) extraction. The chemical composition of the EOs was analyzed, and their plant protection (insects: Spodoptera littoralis, Rhopalosiphum padi, and Myzus persicae; plants: Lactuca sativa and Lolium perenne; fungi: Aspergillus niger; and nematode: Meloidogyne javanica) and antiparasitic (Trypanosoma cruzi, Phytomonas davidi, and antiplasmodial by the ferriprotoporphyrin biocrystallization inhibition test) properties were studied, in addition to the hydrolate by-product. The EOs showed a 1,8-cineole and camphor profile, with quantitative and qualitative chemical differences between the cultivation methods. These oils had moderate insect antifeedant, antifungal, and phytotoxic effects; were trypanocidel; and exhibited moderate phytomonacidal effects, while the hydrolate showed a strong nematicidal activity. Both EOs were similarly antifeedant; the EO from the greenhouse plants (flowering stage) was more biocidal (antifungal, nematicidal, and phytotoxic) than the EO from the aeroponic plants (growing stage), which was more antiparasitic. The major components of the oils (1,8-cineole and camphor), or their 1:1 combination, did not explain any of these effects. We can conclude that these EOs have potential applications as insect antifeedants, and as antifungal or antiparasitic agents, depending on the cultivation method, and that the hydrolate byproduct is a potent nematicidal.

This study was conducted to assess the phytotoxic effect of invasive species: Parthenium hysterophorus L. on the germination, seedling length and biomass of Zea mays, Macrotyloma uniflorum and Triticum aestivum, in order to explore its potential as noxious species. In this study, the allelopathic substances were extracted with distilled water and methanol from the aerial and underground part of P. hysterophorus L. in different concentration (1, 100, 150, 400 mg mL–1). The results of the study revealed that the methanol fraction of roots at 400 mg mL-1 concentration had the highest phytotoxic activity as compared to the double distilled water extract. Germination (%) was observed to be maximum (90%) for Z. mays with double distilled water above ground part extract at 1 mg mL-1 and lowest (10%) for M. uniflorum L. in 400 mg mL-1 both aerial and underground plant extracts at the last day of measurement. Mean shoot and root length were observed highest (17.6cm and 6.1cm respectively) in Z. mays with aerial double distilled water extract at 1 mg mL-1 concentration and it was found lowest (3.2cm and 2.8cm) in M. uniflorum with underground part double distilled water extract at 400 mg mL-1. Biomass was recorded highest (1.97 g/100cm2) in Z. mays in aerial part extract and lowest (0.83 g/100 cm2) in horse gram in underground part extract at concentration of 400mg mL–1 with double distilled water extract. In methanol, both aerial and underground part extracts, the germination observed only at 1mg mL-1 concentration.

Essential oils have secondary metabolites with antibacterial and antifungal properties. In this sense, the objective of this work was to evaluate the phytopathogen incidence and the physiological quality in seeds of Phaseolus vulgaris L. cv. BRS Splendor, treated with different essential oils in different packages and storage times. The essential oils of cinnamon (Cinnamomum zeylanicum), lemongrass (Cymbopogon citratus), clove (Syzgium aromaticum), lemon balm (Melissa officinalis), ginger (Zingiber officinale), sweet orange (Citrus sinensis), peppermint (Mentha piperita) and lemon-taiti (Citrus aurantifolia), commercial fungicide and the control, packed in kraft or pet. At 0, 60, 120 and 180 days after storage of the seeds, the water content were evaluated; first count of germination; percentage of germination; emergence of seedlings; speed germination index, dry matter and blotter test. The treatments with essential oils of C. aurantifolia and C. zeylanicum did not affect the percentage of germination of the seeds during the storage when packed in kraft packaging. At 120 and 180 days after storage, treatments with essential oils of C. aurantifolia and C. zeylanicum did not affect the percentage of germination of the seeds when packed in kraft packaging. There was a significant effect among the packages within the same storage period for the essential oils of C. zeylanicum; C.sinensis and M. officinalis that decreased the incidence of the fungus of the genus Aspergillus spp. The essential oils of C. zeylanicum and S. aromaticum decreased the incidence of Penicillium spp., both stored in pet, the essential oil of C. zeylanicum being similar to the commercial fungicide. The kraft packaging was more efficient in preserving the physiological quality of the treated seeds of Phaseolus vulgaris L. than the pet package. At zero storage time, treatments with C. sinensis and S. aromaticum promoted a negative effect on the physiological quality of the seeds compared to the con, Os óleos essenciais apresentam metabólitos secundários com propriedades antibacteriana e antifúngica. Nesse sentido, objetivou-se com esse trabalho avaliar a incidência de fitopatógenos e a qualidade fisiológica de sementes de Phaseolus vulgaris L. cv. BRS Esplendor, tratadas com diferentes óleos essenciais em diferentes embalagens e tempos de armazenamento. Foram avaliados os óleos essenciais de canela (Cinnamomum zeylanicum), capim-limão (Cymbopogon citratus), cravo da índia (Syzgium aromaticum), erva-cidreira (Melissa officinalis), gengibre (Zingiber officinale), laranja-doce (Citrus sinensis), hortelã-pimenta (Mentha piperita.) e limão-taiti (Citrus aurantifolia), fungicida comercial e a testemunha, embalados em kraft ou pet. Aos 0, 60, 120 e 180 dias após o armazenamento das sementes, avaliou-se o teor de água; primeira contagem da germinação; porcentagem de germinação; índice de velocidade de emergência (IVE), emergência de plântulas, matéria seca e blotter test. Aos 120 e 180 dias após o armazenamento os tratamentos com óleos essenciais de C. aurantifolia e C. zeylanicum não afetaram a porcentagem de germinação das sementes quando acondicionadas em embalagem kraft. Entre as embalagens houve diferença significativa quando as sementes foram tratadas com os óleos essenciais de C. zeylanicum; C.sinensis e M. officinalis que reduziram a incidência do fungo do gênero Aspergillus spp. Os óleos essenciais de C. zeylanicum e S. aromaticum diminuíram a incidência de Penicillium spp., ambos armazenados em pet, tendo o óleo essencial de C. zeylanicum o comportamento semelhante ao fungicida comercial. A embalagem kraft foi mais eficiente em preservar a qualidade fisiológica das sementes tratadas de Phaseolus vulgaris L. do que a embalagem pet. No tempo zero de armazenamento, os tratamentos com C. sinensis e S. aromaticum promoveram efeito negativo sobre a qualidade fisiológica das sementes comparado a testemunha. O óleo essencial de C. citratus influenciou negativamente n

[SPA] Se evaluaron los efectos que tiene la aplicación de agua regenerada (AR), en combinación con estrategias de riego deficitario controlado (RDC), sobre los parámetros fisiológicos y de desarrollo de la planta de pomelo, destacando los posibles cambios en la eficiencia del uso del agua (EUA) y del nitrógeno (EUN) y realizando una caracterización de los elementos estructurales y constituyentes a nivel foliar. Se observó una mejora de la EUA en los tratamientos regados con AR y, por el contrario, una disminución de la EUN, del contenido en clorofila, de los niveles de intercambio gaseoso y, además, dio lugar a una potencial acumulación de sales a nivel foliar. [ENG] Effects of the application of reclaimed water (RW), combined with strategies of deficit irrigation (RDI) on physiological parameters and development of grapefruit plant were evaluated, highlighting the potential changes in water (WUE) and nitrogen (NUE) use efficiency and performing a characterization of structural elements and constituents at leaf level. RW improved the WUE and, conversely, decreased the NUE, the chlorophyll content and levels of gas exchange. In addition, the application of RW resulted in a potential accumulation of salts at the level foliar.

Arsenic (As) and cadmium (Cd) are noxious and carcinogenic pollutants that can be removed from water by using emerging, ecofriendly, phytofiltration technology that employs Micranthemum umbrosum. After culturing M. umbrosum for 7 days in a hydroponic experiment, accumulation of 1219±44.11 µg As g−1 and 799.40±30.95 µg Cd g−1 were observed in the leaves, from 1000 µg As L−1 and 1000 µg Cd L−1 of water, respectively. Plant and water samples were analyzed for assessing the As and Cd accumulations, translocations, phytotoxic effects, uptake mechanisms and kinetics, and for evaluating the potential of M. umbrosum in As and Cd phytofiltration. The uptake pattern was leaf>stem>root for both pollutants. The plant showed higher resistance to As than to that to Cd. Uptake of inorganic As species was much greater than that of organic As and was found at above the substrate concentration. However, Cd showed similar uptake pattern to that of inorganic As species, and the data was better fit to a non-linear than a linear model. Low molecular weight substances that have thiol group(s) may be responsible for the binding of As in plants whereas Cd showed a different mechanism to that of As. M. umbrosum showed good As phytofiltration capabilities without any phytotoxic effects, but it was found to be a moderate accumulator of Cd with some phytotoxic effect compare to some other previously studied plant.

The most widespread application of reuse of treated / reclaimed domestic wastewater is agricultural irrigation. The common regulations on quality of reclaimed water for reuse contemplated physicochemical and biological parameters to minimize health risks, but rarely taken into account phytotoxic parameters that may be limiting for agricultural applications. The physicochemical and phytotoxic parameters change to advance the degree of purification / regeneration of wastewater, so it is of interest to know what stage of the installation provides adequate water for irrigation. This paper presents a correlation study of phytotoxicity with physicochemical parameters in water samples taken at the end of each of the stages of conventional treatment of domestic sewage, including biological reactor activated sludge treatment and tertiary sand filtration, chlorination, filtration cartridge and desalination by electrodialysis reversal. In each sample was measured. Chemical oxygen demand, pH, conductivity, organic carbon, total phosphorus, soluble proteins and ions of Na, K, Ca, Mg, B, F and Cl criteria phytotoxicity were evaluated by Lactuca sativa biomarker.Results showed significant reductions in physicochemical parameters of electrodialysis process, while the effects of phytotoxicity showed reductions in the processes before the final stage of electrodialysis.We conclude that the physico-chemical, together with the biomarker parameters are aspects of practical interest that relates the type of treatment with physical-chemical

Allelopathy is a biological phenomenon in which an organism produces one or more biochemicals that influence the growth, survival, and reproduction of other organisms. Allelopathy has been the subject of a great deal of research in chemical ecology since the 1930s. The characterization of the factors that influence this phenomenon has barely been explored, mainly due to the complexity of this area. The main aim of the research carried out to date has been to shed light on the importance of these interactions in agroecosystems, especially in relation to the interactions between crops and weeds. Herein we report the characterization of a complete allelochemical pathway involving benzoxazinones, which are known to participate in allelopathic plant defense interactions of several plants of high agronomic interest. The production of the defense chemicals by a donor plant (crop), the route and transformations of the chemicals released into the environment, and the uptake and phytotoxic effects on a target plant (weed) were all monitored. The results of this study, which is the first of its kind, allowed a complete dynamic characterization of the allelopathic phenomenon for benzoxazinones.

Onopordum acanthium L. (Asteraceae) is a plant native to southern Europe and southwestern Asia, but it is invasive in disturbed areas and agricultural fields around the world, causing many agronomic problems by interfering with crops or preventing animals from grazing on pastures. Allelopathy could be one of the reasons that this plant has spread over different continents. The aim of the present study was to bioprospect O. acanthium leaf extracts through the isolation and purification of allelopathic secondary metabolites with phytotoxicity to explain their invasive behavior. Phytotoxic activity was tested using etiolated wheat coleoptiles. The most active extract was selected to perform a bioassay-guided isolation of two flavonoids, pectolarigenin (1) and scutellarein 4’-methyl ether (2), and two sesquiterpene lactones, elemanolide 11(13)-dehydromelitensin b-hydroxyisobutyrate (3) and acanthiolide (4). All compounds were isolated for the first time from O. acanthium, and acanthiolide (4) is described for the first time. Compound 3 strongly inhibited the growth of wheat coleoptiles and 1 showed an intermediate effect. The results indicate that these compounds could contribute to the invasion of O. acanthium in ecological systems and agricultural fields.

En ese trabajo se estudia la concentración de elementos traza tóxicos en los depósitos de lodos (relaves) abandonados por la industria minera en Almería (España), los suelos del entorno próximo y las plantas que los colonizan y representan una vía de incorporación de dichos elementos en la cadena trófica. La industria minera antigua dejó toda una serie de instalaciones abandonadas en diferentes zonas de Andalucía, entre las que destacan por presentar altos contenidos en metales, los depósitos de residuos en forma de lodos generados en el proceso de flotación. En este estudio se trata el caso concreto de los depósitos de lodos de Mina La Solana (Almócita, Almería), donde se ha realizado una caracterización geoquímica de los depósitos y de los suelos de su entorno, en función al contenido en algunos elementos traza. Se han caracterizado muestras de las plantas que enraízan en dichos residuos para determinar la concentración que presentan en los mismos elementos traza. Los resultados muestran que los lodos presentan altos contenidos en Pb (concentración media 6800 ppm) y Zn (concentración media 22 000 ppm). Estos elementos no aparecen en forma soluble en agua, los test de lixiviación dan valores de concentración muy bajos (≤10 ppm de Pb y ≤ 2 ppm de Zn). De la misma forma se ha determinado una concentración alta de los mismos elementos en los restos vegetales, con un valor del Pb hasta los 210 ppm y 1300 ppm de Zn. Este hecho pone de manifiesto la capacidad de las plantas para alterar la movilidad de los elementos presentes en el sustrato donde enraízan estableciéndose una transferencia hacia la cadena trófica., This work presents a study of the concentration of toxic trace elements in abandoned sludge deposits (tailings) by mining in Almeria (Spain), soils and plants that colonize and represent a way to incorporate those elements in the food chain. The old mining industry left a number of abandoned facilities in different parts of Andalusia, with tailings standing out. They were generated in the flotation process, and usually deposited and left on streambeds. Tailings composition vary depending on the type of ore and treatment additives, but usually the contents of heavy metals are high, because recovery was not very good in the mineral processing technique used in the early 20th century facilities. In this study we analyze the case of Mina La Solana tailings, located in Almócita (Almería, SE Spain). We carried out a geochemical characterization of trace element content. Furthermore, we also studied the geochemical trace element content in plants that were rooted in the tailings. The results show that tailings have high Pb content (average concentration 6800 ppm) and Zn (average concentration 22 000 ppm). These elements are not mobile soluble fractions; leaching tests give very low concentration levels (≤ 10 ppm Pb and ≤ 2 ppm Zn) in water. We found high concentrations of the same elements in plants, with a value of up to 210 ppm Pb and 1300 ppm Zn. This demonstrates the ability of plants to alter the mobility of the elements present in the substrate where they are rooted and thus providing a transfer to the food chain through feeding species.

Foliar blight of soybean is one of the major fungal diseases. Rhizoctonia solani isolated from soybean growing in tarai regions of Uttarakhand. Six isolates of R. solani has been characterized on the basis of cultural and physiological nature such as colony diameter, growth, colour and sclerotia formation were recorded. Potato Dextrose Agar (PDA) was found best for growth and development. Two isolates (Lakhimpur and Pantnagar) covered the whole plates (90 mm) in 48 hrs. However, maximum number of sclerotia and weight was recorded on Czapek Dox agar medium. Overall radial growth supporting is recorded Corn Meal Agar Medium. Varied range of temperatures i.e. 10, 15, 25, 30, 35 and 400C was tested and found better growth of different isolates of R. solani at 10 - 400C, with an optimum growth temperature at 300C. Isolates were grown on five broth media (Asthana & Hawkers, Potato Dextrose Agar, Czapek’s Dox Agar, Corn Meal Agar and Richards Agar) for fresh, dry weight and oat meal broth culture filtrates of all isolates was used in phytotoxic effects. It recorded that maximum fresh and dry weight was observed on corn meal agar medium. The maximum reduction in radical and plumule length of germinating seeds were recorded in Haldichaur isolate.

Pentacyclic triterpenes are abundant in the plant kingdom and have a wide array of pharmacological activities. They also have insect antifeedant effects and therefore apparently play a role in plant defense. In this paper, we describe the insecticidal activity of pentacyclic triterpenes of plant origin from different chemical classes on several insect pests (Spodoptera littoralis, Leptinotarsa decemlineata and Myzus persicae), their phytotoxic properties and their selective cytotoxic effects on insect-derived Sf9 and mammalian CHO cells. We also discuss the role they play in plant defense based on these activities.

A new lupane type triterpene (1), together with betulinic acid (2), friedelin (3), aristolochic acid I (4), alpinumisoflavone (5) and 4’-O-methylepinumisoflavone (6) have been isolated from the leaves of Thecacoris annobonea. The structure of the new compound was elucidated on the basis of 1 and 2D NMR experiments. The isolated compounds were evaluated for their phytotoxicity and antimicrobial activity. 1 exhibited significant antimicrobial activity at 30 μg/ml and compounds 1, 2, 3, 4, 5 and 6 inhibited root growth lettuce at 100 μg/ml.Â

A new lupane type triterpene (1), together with betulinic acid (2), friedelin (3), aristolochic acid I (4), alpinumisoflavone (5) and 4’-O-methylepinumisoflavone (6) have been isolated from the leaves of Thecacoris annobonea. The structure of the new compound was elucidated on the basis of 1 and 2D NMR experiments. The isolated compounds were evaluated for their phytotoxicity and antimicrobial activity. 1 exhibited significant antimicrobial activity at 30 μg/ml and compounds 1, 2, 3, 4, 5 and 6 inhibited root growth lettuce at 100 μg/ml.Â

We investigated the qualitative and quantitative seasonal variation of the leaf and fruit oils of the Macaronesian endemism Laurus novocanariensis and their plant defensive potential. The monoterpene fraction dominated the leaf (74%) and berry essential oils (73e44%, ripeeunripe). The insect antifeedant effects of these oils were species- and season-dependent against the aphids (Myzus persicae and Rhopalosiphum padi). Overall, the biological effects of these oils correlated with the oxygenated terpene fraction. Among the pure components tested, b-caryophyllene and its oxide were strong antifeedants to Leptinotarsa decemlineata and Spodoptera littoralis. The aphids responded to b-ocimene, b-pinene, 1,8-cineole, linalool (antifeedants) and linalool oxide (attractive to M. persicae). The antifungal effects of the leaf oils on Fusarium spp. were season-dependent. b-Caryophyllene oxide proved to be a strong antifungal. L. novocanariensis oils inhibited Lactuca sativa germination and radicle elongation, the leaves being more effective. Linalool also inhibited seed germination.

Pyrrolizidine alkaloid (PA) producing plants belonging to the Boraginaceae (Echium wildpretti) and Asteraceae (Canariothamnus palmensis, Kleinia neriifolia, Pericallis appendiculata, Pericallis echinata, Pericallis hansenii, Pericallis multiflora, Pericallis steetzii and Senecio bollei) were selected to study their alkaloidal composition and the defensive properties (antifeedant and phytotoxic effects) of their ethanolic and alkaloidal extracts plus their isolated PAs against insects (Spodoptera littoralis, Leptinotarsa decemlineata, the aphids Myzus persicae and Rhopalosiphum padi) and Lactuca sativa seeds. We also tested the selective cytotoxic effects of these PAs on insect-derived Sf9 and mammalian CHO cells. Most of the insect antifeedant effects were found in the ethanolic extracts. The isolated PAs had species- and structure-dependent antifeedant effects and all of them decreased L. sativa radicle growth, suggesting a specific mode of action against insects and a generalized one against plants. Given the relatively low alkaloid content of these species, we assume that their herbivore defenses are not only alkaloid-based.

Eucalyptus globulus L.(Myrtaceae) stared as antisocial tree  for  social  forestry  (Kohli,  1987)  is commonly transplanted through out India on roadsides, bare  lands  and  boundaries  of  crop  fields without considering its allelopathic effects on crop  plants,  especially cereals  and  pulses.  The aerial parts, especially leaves of this  tree contain  volatile tarpenes (Del  Moral  and  Muller, 1970),  water soluble toxins and growth inhibitors. (Grummer and Beyer, 1960 and Al-Mousawi, Al-Naib,1976 and Pandhy et al. 1992). Toxic effects of different concentrations of leaf extract of Eucalyptus globulus (Viz-5,10, 15,  20  &  25  percent)  was  studied  on  percentage  of  seed  germination,their  survival, growth of radical and plumule and establishment of secondary roots on three species of Vicia-V. narborensis, Vicia benghalensis. and V. faba.In the present investigation each concentration showed inhibitory  effects  of  the  above  parameters  which  gradually  increases  with  increasing   concentra- tions of the leaf extract. Delayed germination was also noticed in the treated seeds. Vicia narborensis proved to be more sensitive to these toxic leachates than the other  two species.  The above findings clearly showed  that  the  transplantation  of  Eucalyptus  species  on boundaries of  crop  plants  should be totally banned. Further investigation on its Cytotoxic effect (if any) is in progress.

Studies were conducted in a greenhouse to determine the phytotoxic effect and uptake capacity of Zn, Cr and Cd by the water hyacinth Eichhornia crassipes. Results show that among the three elements tested, Cd was the most phytotoxic, showing up some necrosis in the plant when the concentration was greater than 2.5 ppm. In the case of Cr and Zn, the phytotoxicity produced the appearance of chlorosis in the aerial part of the plant. For the tested rates of Cr (maximum 9 ppm) no reduction of productivity was found, whereas in the case of Zn the concentration of 9 ppm in solution caused a 30% reduction in the weight. As for the heavy metal absorption, it was proved that after 24 days of growth, the heavy metals were totally depleted from the nutritive solution suggesting complete absorption of these metals by the plants. © 1993.

Recently, a solid-phase plant bioassay was developed to test sediment for contaminants that are potentially phytotoxic and may be bioaccumulated by plants (Folsom and Lee 1981a; Folsom, Lee, and Bates 1981). The solid phase plant bioassay was shown to be an excellent tool for predicting whether or not contaminants (e.g., zinc and cadmium) were potentially bioaccumulated by the saltwater plant S. alterniflora. Folsom and Lee (1981a) pointed out, however, that the DTPA extraction data indicated that plant uptake from air-dried oxidized saltwater sediment would be substantially greater than from the same saltwater sediment under flooded reduced conditions. In addition, they suspected greater plant uptake once the excess salts were leached out and the sediments were dried. This technical note reports results of modifications to the original solid-phase plant bioassay to pursue this assumption. pg 1.&2. JMD

THIS IS A PROGRESS REPORT ON AEROJET'S STUDIES OF EXPERIMENTS CURRENTLY UNDERWAY (E.G., PLANT GROWTH AND DIMP AND DCPD LYSIMETER TESTS). TESTS ARE IN PROGRESS TO DETERMINE THE STABILITY OF DIMP AND DCPD IN INTIMATE CONTACT WITH MOISTENED TOP SOIL. THE ANALYTICAL METHOD PROPOSED FOR DCPD WILL REQUIRE SOME MODIFICATION. THREE OF THE FIVE SOILS TO BE USED IN THE LYSIMETER EXPERIMENTS HAVE BEEN OBTAINED, PROCESSED AND LOADED INTO SIX LYSIMETERS. DISTILLED WATER HAS BEEN PASSED THROUGH ALL OF THEM. TEN PLANTS OF ONE PLANT EACH OF THE PLANTS ENUMERATED IN LAST MONTHS' REPORT HAVE BEEN STARTED IN WATER CULTURE BATHS. PLANT TEST TUBS WERE INOCULATED WITH CONTAMINANTS, CONDITIONS AND PHYTOTOXIC SYMPTOMS WERE NOTED. JMD