Allelopathic activiti of eastern galega seeds with oil crops

Relevanсe. The novelty of our research lies in the fact that for the first time the allelopathic interaction of eastern galega seeds with a wide range of oilseeds is being studied. The aim of this work is to study the allelopathic effect in the initial stages of plant ontogenesis. The objectives of the study were to identify cultures with a positive and negative impact on the growth and development of sprouts of eastern galega. The objects of research were eastern galega Magister, false saffron Alexandrite, saperda mustard Lux, spring rape Tavrion, hemp Nadezhda, spring cress Iskra, white mustard Lucia, abyssinian colewort Polet, ethiopian niger seed Medea, oil radish Fiolina, damascene fennelflower Yalita, hybrid sunflower P63 LE 10 (XF 3020), winter camelina Baron, spring camelina Velez, oilseed flax Istok. The experiments were carried out in two layouts in 2019–2020 on the basis of a separate division of the Federal research center for fiber crops in the Penza region.Methods. The evaluation of allelopathic activity was carried out using a method that involves the germination of plant seeds, followed by the calculation of the percentage of germination. The number of seeds and seedlings at different stages of ontogenesis was determined along with measuring the length of the root, stem and leaf.Results. At the initial stages of ontogenesis, a weak negative allelopathic effect on the eastern galega is exerted by the abyssinian colewort Polet — the number of fullfledged seedlings was -6,1% to the control. A positive effect on the germination and development of galega seedlings is exerted by damascene fennelflower Yalita (+8,3% to control), ethiopian niger seed Medea (+8,1 to control), oilseed flax Istok (+6,4% to control). In general, the length of the galega seedling was at the level of control with damascene fennelflower and ethiopian niger seed is 3,27 and 3,24 cm (-0,40 and 0,43 cm respectively). A significant decrease is observed in the variants with oilseed flax, spring camelina, winter camelina, spring rape, false saffron, sunflower, saperda mustard, white mustard, hemp, abyssinian colewort and spring cress — from 2,81 to 1,66 cm (-0,86–2,01 cm to control).

Benthic Cyanobacterial Diversity and Antagonistic Interactions in Abrolhos Bank: Allelopathy, Susceptibility to Herbivory, and Toxicity

Benthic cyanobacterial mats (BCMs) are conspicuous components of coral reef communities, where they play key ecological roles as primary producers among others. BCMs often bloom and might outcompete neighboring benthic organisms, including reef-building corals. We investigated the cyanobacterial species composition of three BCMs morphotypes from the marginal reef complex of Abrolhos Bank (Southeastern Brazil). Also, we assessed their allelopathic effects on coral zooxanthellae, their susceptibility to herbivory by fish, and their toxicity to brine shrimp nauplii. Morphology and 16S rDNA sequencing unveiled the cyanobacteria Moorena bouillonii, Okeania erythroflocculosa, Adonisia turfae, Leptolyngbya sp., and Halomicronema sp. as components of BCMs from Abrolhos. BCMs cell-free filtrates and extracts exerted an allelopathic effect by reducing the growth of the ex hospite Symbiodinium sp. in culture. BCMs-only treatments remained untouched in field susceptibility assays in contrast to macroalgae only and mixed BCMs-macroalgae treatments that had the macroalgae fully removed by reef fish. Crude aqueous extracts from BCMs were toxic to brine shrimps in acute assays. Besides unveiling the diversity of BCMs consortia in Abrolhos, our results cast some light on their allelopathy, antiherbivory, and toxicity properties. These antagonistic interactions might promote adverse cascading effects during benthic cyanobacteria blooms and in gradual shifts to BCMs-dominated states.

Allelopathic Effect of Aqueous Extracts of Stinkwort (Dittrichia graveolens L.) on Germination and Growth of Some Weed Species

The experiment was implemented by CRD design with three replications and lasted for 40 days, from 5 October until 15 November 2020. Four extract concentrations of D. graveolens 0, 2, 6, and 10% were used. The concentration of 0% was considered as control. The allelopathic effect has been studied on five weed species; Amaranthus retroflexus L., Portulaca oleracea L., Lolium multiflorum Lam., Sorghum halepense L., and Cuscuta campestris Yunck. The research also aimed to determine the effect of Stinkwort extract on the growth of tomato seedlings. All concentrations affected seed germination for all studied weeds. The concentration of 10% was more influential in growth-related indicators compared to other concentrations. The seeds of L. multiflorum and rhizomes of S. halepense were more tolerant to D. graveolens allelochemicals in germination rate than A. retroflexus, P. oleracea, and C. campestris. All concentrations led to a reduction in the weed heights and the wet and dry weights compared with the controls. The effect of the extract with various concentrations was catalytic for the growth of tomato seedlings, as the average height of tomato seedlings was in direct proportion to the concentration.

Allelopathic Effect of Aqueous Extracts of Stinkwort (Dittrichia graveolens L.) on Germination and Growth of Some Weed Species

The experiment was implemented by CRD design with three replications and lasted for 40 days, from 5 October until 15 November 2020. Four extract concentrations of D. graveolens 0, 2, 6, and 10% were used. The concentration of 0% was considered as control. The allelopathic effect has been studied on five weed species; Amaranthus retroflexus L., Portulaca oleracea L., Lolium multiflorum Lam., Sorghum halepense L., and Cuscuta campestris Yunck. The research also aimed to determine the effect of Stinkwort extract on the growth of tomato seedlings. All concentrations affected seed germination for all studied weeds. The concentration of 10% was more influential in growth-related indicators compared to other concentrations. The seeds of L. multiflorum and rhizomes of S. halepense were more tolerant to D. graveolens allelochemicals in germination rate than A. retroflexus, P. oleracea, and C. campestris. All concentrations led to a reduction in the weed heights and the wet and dry weights compared with the controls. The effect of the extract with various concentrations was catalytic for the growth of tomato seedlings, as the average height of tomato seedlings was in direct proportion to the concentration.

A, The ALLELOPATHIC EFFECT OF CINNAMOMUM VERUM ON EMERGENCE AND SEEDLING GROWTH OF RADISH (Raphanus sativus)

Crop plants release biochemicals into surrounding environment that help in obtaining maximum yield of crop by acting bioherbicide at high concentration and plant growth hormone at low concentration. Therefore, this study was planned at Department of Agronomy in Weed Science Laboratory, University of Agriculture Faisalabad during Winter 2018 to evaluate the hermetic effects of Cinnamomum verum (Dalchini) on vegetable crop Radish (Raphanus sativus) and determination and quantification Phenolic compound present in aqueous extract of bark of C. verum. The experiments were laid out under completely randomized design (CRD) having three replications. The aqueous extracts of C. verum was used on radish seeds at different concentrations (2.5%, 5%, 10%, 20%, 40% and 80%). Data regarding seed germination and seedling growth (shoot length, root length, shoot fresh weight, root dry weigh) of radish were recorded following standard procedures. Results of our study revealed that at higher concentration act as bioherbicide and produced inhibitory effects on R. sativus while at low concentration it shows hermetic effect and promoted the seedling growth. aqueous extract showed concentration. Among different Phenolic compound (Syringic acid, p-crumeic, Ferulic acid, Quercetion and Gallic acid) determine in aqueous extract of barck of C. verum Maximum Quercetion (12.3 %) and minimum Syringic acid (0.60 %) was found. Therefore, it was concluded from this study that aqueous extract of C. verum can be used as bioherbicides at higher concentration to control weed while at low concentration as plant growth regulator.

Allelopathic activity of Piptadenia moniliformis Benth. on the physiological potential of seeds of Amburana cearensis Allem.

The adoption of agroforestry systems or reforestation programs contributes to the economy of a region in a sustainable way, since the adopted species can be exploited by the cosmeceutical and pharmaceutical industries. For the establishment of plant species in a given area, studies are needed on the interaction that can develop between them, with emphasis on research on allelopathy. Given the above, the aim of this study was to evaluate the allelopathic effect of the aqueous extract of leaves of the native species Piptadenia moniliformis on the initial development of the forest species Amburana cearensis. The aqueous extract was used at different concentrations. (0 - water, 25, 50, 75 and 100%), adopting a completely randomized design. The following characteristics were evaluated: emergence percentage, emergence speed index, mean emergence time, shoot and root length and total shoot, root and total dry part of normal seedlings. The 100% concentration of the aqueous extract of P. moniliformis leaves reduced the emergence percentage of A. cearensis seedlings. A smaller number of normal seedlings was observed at concentrations of 75 and 100%. The initial development of seedlings was hampered by the increase in extract concentrations. The aqueous extract of fresh leaves of P. moniliformis provides a negative allelopathic effect for both emergence and early development of A. cearensis seedlings, therefore intercropped cultivation among the forest species is not recommended.