Growth regulation of bermudagrass (Cynodon dactylon) and zoysiagrass (Zoysia japonica) with glyphosate.

Glyphosate can generate positive effects on turfgrass maintenance as a form of growth control by decreasing the expenses associated with mowing. However, there is little information about the effects of this herbicide on turfgrasses. This study aimed to evaluate the response of bermudagrass and zoysiagrass to the herbicide glyphosate as a growth regulator. Two studies were performed in a greenhouse and repeated at different times. The treatments involved application of glyphosate at 10 different rates (0, 5.625, 11.25, 22.5, 45, 90, 180, 360, 720, and 1.440 g ae ha-1) with four replicates. Evaluations of green cover by digital analysis, injury, and plant height were performed at 7, 14, 21, and 28 days after application, and shoot dry matter of clippings was determined for the last evaluation period. Bermudagrass and zoysiagrass presented variedtolerance to glyphosate toxicity. Overall, the digital analysis showed that green content was negatively influenced by the increase in visual injury caused by glyphosate application. Moreover, increasing the glyphosate rate decreased plant height and shoot dry matter in both turfgrasses. Glyphosate application rates up to 45 g ae ha-1 for bermudagrass and 90 g ae ha-1 for zoysiagrass decreased plant growth without affecting the factors analyzed in this study.

Histological and biochemical changes induced by gibberellic acid in the livers of pregnant albino rats and their offspring: ameliorative effect of Nigella sativa.

Gibberellic acid (GA3), a plant growth regulator, is widely used in agriculture in many countries to accelerate the growth of fruits and vegetables. We designed histological, immunohistochemical, and biochemical studies to evaluate the deleterious effects of GA3 on the livers of adult pregnant rats and their offspring and to assess the possible ameliorative effect of Nigella sativa Linn. (NsL.oil) against these effects. Twenty-four pregnant albino rats were utilized, randomly divided into four groups: The first group was used as a negative control group, while the second group (positive control group) was provided NsL.oil at a dose of 100 mg/kg of bodyweight. Animals in the third group (GA3 group) were provided 200 ppm of GA3 dissolved in distilled water from the 7th day of pregnancy until 1 day after delivery. Animals in the last group (GA3 + NsL.oil group) were provided GA3 and NsL-oil at the same doses as mentioned above. One day after delivery, each group of lactating mothers and their pups were sacrificed. Liver specimens were subjected to histopathological, immunohistochemical, and biochemical examinations. The livers of rats from the GA3 group showed various degenerative changes, being predominant in the livers of the mothers compared with the offspring. The pathological changes in the livers of the offspring suggested transplacental passage of GA3. The results reveal that GA3 ingestion induced a significant increase in alanine aminotransferase (ALT) and aspartate transaminase (AST) activities in the serum of both groups of mothers and their pups, with a significant increment in lipid peroxidation as evidenced by enhanced malondialdehyde (MDA) levels with significant decrements in superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) enzymatic activities in comparison with control groups in the liver of mothers and their offspring. Histopathological examination showed hydropic degeneration and inflammatory cellular infiltration. Additionally, there was fibrosis around the portal area. Moreover, immunolocalization revealed downregulation of the expression of the antiapoptotic marker Bcl-2 in hepatocytes and upregulation of the expression of the apoptotic marker Bax in the treated group. Concomitant use of NsL.oil along with GA3 exerted a considerable reversing effect on histopathological and biochemical changes in the livers of mother groups and their pups. The results of the present study highlight the consequences of exposure to GA3 during pregnancy on hepatic tissue in both mothers and their offspring. Furthermore, the study suggests use of NsL.oil as a potential protective strategy against GA3-induced liver toxicity.

Interactive effects of supplemental ultraviolet-B radiation and indole-3-acetic acid on Coleus forskohlii Briq.: Alterations in morphological-, physiological-, and biochemical characteristics and essential oil content.

Ultraviolet (UV)-B radiation and the growth hormone indole-3-acetic acid (IAA) have been known to cause various changes in plants at morphological and physiological levels as individual entities, but their interactive effects on the overall plant performance remain practically unknown. The present study was conducted under near-natural field conditions to evaluate the effects of supplemental (s)-UV-B (ambient+3.6kJm-2day-1) treatment alone, and in combination with two doses of IAA (200ppm and 400ppm) exogenously applied as foliar spray on various growth-, morphological-, physiological-, and biochemical parameters of an indigenous medicinal plant, Coleus forskohlii. Under s-UV-B, the plant growth and morphology were adversely affected (along with reductions in protein- and chlorophyll contents) with concomitant increase in secondary metabolites (as substantiated by an increase in the activities of various enzymes of the phenylpropanoid pathway) and cumulative antioxidative potential (CAP), suggesting the plant's capability of adaptive resilience against UV-B. The essential oil content of the plant was, however, compromised reducing its pharmaceutical value. IAA application at both doses led to a reversal in the effects caused by s-UV-B radiation alone; both the plant growth as well as the essential oil content improved, especially at the higher IAA dose, suggesting its ameliorative role against UV-B induced oxidative stress, and also in improving the plant's medicinal value.

Essential oil of Artemisia scoparia inhibits plant growth by generating reactive oxygen species and causing oxidative damage.

We investigated the chemical composition and phytotoxicity of the essential oil extracted from leaves of Artemisia scoparia Waldst. et Kit. (red stem wormwood, Asteraceae). GC/GC-MS analyses revealed 33 chemical constituents representing 99.83% of the oil. The oil, in general, was rich in monoterpenes that constitute 71.6%, with beta-myrcene (29.27%) as the major constituent followed by (+)-limonene (13.3%), (Z)-beta-ocimene (13.37%), and gamma-terpinene (9.51%). The oil and beta-myrcene were evaluated in a dose-response bioassay under laboratory conditions for phytotoxicity against three weeds-Avena fatua, Cyperus rotundus, and Phalaris minor. A significant reduction in germination, seedling growth, and dry matter accumulation was observed in the test weeds. At the lowest treatment of 0.07 mg/ml Artemisia oil, germination was reduced by 39%, 19%, and 10.6% in C. rotundus, P. minor, and A. fatua, respectively. However, the inhibitory effect of beta-myrcene was less. In general, a dose-dependent effect was observed and the growth declined with increasing concentration. Among the three weeds, the inhibitory effect was greatest on C. rotundus, so it was selected for further studies. We explored the explanation for observed growth inhibition in terms of reactive oxygen species (ROS: lipid peroxidation, membrane integrity, and amounts of conjugated dienes and hydrogen peroxide)-induced oxidative stress. Exposure of C. rotundus to Artemisia oil or beta-myrcene enhanced solute leakage, indicating membrane disintegration. There were increased levels of malondialdehyde and hydrogen peroxide, indicating lipid peroxidation and induction of oxidative stress. We conclude that Artemisia oil inhibits plant root growth through generation of ROS-induced oxidative damage.

Effects of gibberellin A(3) on growth and microcystin production in Microcystis aeruginosa (cyanophyta).

Environmental factors that affect the growth and microcystin production of microcystis have received worldwide attention because of the hazards microcystin poses to environmental safety and public health. Nevertheless, the effects of organic anthropogenic pollution on microcystis are rarely discussed. Gibberellin A(3) (GA(3)) is a vegetable hormone widely used in agriculture and horticulture that can contaminate water as an anthropogenic pollutant. Because of its common occurrence, we studied the effects of GA(3) on growth and microcystin production of Microcystis aeruginosa (M. aeruginosa) PCC7806 with different concentrations (0.001-25mg/L) in batch culture. The control was obtained without gibberellin under the same culture conditions. Growth, estimated by dry weight and cell number, increased after the GA(3) treatment. GA(3) increased the amounts of chlorophyll a, phycocyanin and cellular-soluble protein in the cells of M. aeruginosa PCC7806, but decreased the accumulation of water-soluble carbohydrates. In addition, GA(3) was observed to affect nitrogen absorption of the test algae, but to have no effect on the absorption of phosphorus. The amount of microcystin measured by enzyme-linked immunosorbent assay (ELISA) increased in GA(3) treatment groups, but the stimulatory effects were different in different culture phases. It is suggested that GA(3) increases M. aeruginosa growth by stimulating its absorbance of nitrogen and increasing its ability to use carbohydrates, accordingly increasing cellular pigments and thus finally inducing accumulation of protein and microcystin.

Suppressive effects of Calendula micrantha essential oil and gibberelic acid (PGR) on repro ductive potential of the Mediterranean fruit fly Ceratitis capitata Wied. (Diptera: Tephritidae).

The volatile oil of Calendula micrtantha plant was extracted and the components were identified by Gc/Ms. Adulticidal efficiency of the volatile oil and gibberelic acid "plant growth promoting hormone" as well as their mixture was assessed against the Mediterranean fruit fly Ceratitis capitata. The result showed that the two compounds capable have characteristic resembling to insect juvenile hormones and have suppressive effect on reproductive potential. They induced the significant disturbances in the ovarian protein fraction and the amino acids patterns.

Developmental toxicology of solamargine and solasonine glycoalkaloids in frog embryos.

As part of an effort to improve the safety of plant foods, a need exists to define the relative toxicities of structurally different glycoalkaloids and metabolites which may be present in Solanum plant species such as potatoes, tomatoes and eggplants. The objectives of this study were to determine the relative toxicities and the modes of action of the eggplant (Solanum melongena) glycoalkaloids solamargine and solasonine in Xenopus laevis frog embryos, using membrane potential and embryo growth and teratogenicity assays. In the cell membrane assays, adverse effects on embryos were evaluated by measuring membrane potentials using an electrochromic dye, di-4-ANEPPS, as a fluorescence probe for the integrity of the membranes. In the embryo growth and teratogenesis assays, the survival of the embryos and organ malformations was used as an index of embryo toxicity. The relative potencies of glycoalkaloids are similar for frog embryo effects (survival and teratogenicities) and for membrane effects (membrane potential). Experiments with solasonine at pH 6 and 8 suggest that the unprotonated form of the glycoalkaloids appears to be involved in the membrane effects. The nature of the carbohydrate side-chains of the steroidal glycosides governs relative potencies. The possible significance of the findings to food safety and plant physiology and possible application of the membrane assays to bacterial toxins are discussed.

Comparative study of plant growth hormone (herbicide) toxicity in various biological subjects.

Due to their widespread distribution and toxic nature, herbicides may have a serious impact on the environment and exert adverse effects on associated organisms. The present study was conducted to determine the acute toxicological effects of some plant growth hormones used as herbicides on four biological subjects and compare the subjects' sensitivity to individual testing substances. The herbicides 4-(indol-3-yl)acetic acid C10H9O2N (IAA), N6-(beta 2-isopentenyl)adenosine (pi-indolylpropionic acid) C11H11O2N (IPA), 2,4-dichlorophenoxyacetic acid C8H6O3Cl2 (2,4-D), 4-chloro-2-methylphenoxyacetic acid C9H9O3Cl (MCPA), and 1,napthylacetic acid C12H10O2 (NAA) were tested and the following biological subjects were used: Daphnia magna, Tubifex tubifex, Scenedesmus quadricauda, and seeds of Sinapis alba. For S. alba, the influence of herbicides on seed germination (G) and root growth inhibition (I) was observed. For T. tubifex, the tests lasted 96 hr, for D. magna 48 hr, for S. quadricauda 20 days, and for S. alba 72 hr. The rank order of toxicity of herbicides used for T. tubifex was NAA > IAA > IPA > 2,4-D > MCPA; for D. magna. NAA > IAA > IPA > MCPA > 2,4-D; for S. quadricauda, IAA > IPA > NAA > MCPA > 2,4-D; for S. alba seed germination, NAA > IPA > 2,4-D > MCPA > IAA; and for root growth inhibition. NAA > 2,4-D > MCPA > IAA > IPA.(ABSTRACT TRUNCATED AT 250 WORDS)

Genotoxicity evaluation of Rastim 30 DKV, the plant growth regulator, on five test systems.

The possible mutagenic activity of Rastim 30 DKV, a new plant growth regulator, was studied on five model test systems. It did not increase the frequency of His+ revertants in Salmonella typhimurium strains TA97, TA98, TA100, TA1535, TA1538 in the absence and the presence of S9 mix. It slightly increased rates of genetic changes in Saccharomyces cerevisiae, mainly convertants at the tryptophan locus. No clastogenic effect was observed after Vicia faba root-tip meristem treatment, and at the lowest concentration used its mitotic activity was significantly increased. No chlorophyll mutants after the treatment of two cultivars of barley were observed. Though no sex-linked recessive lethals were scored in Drosophila melanogaster males, the rates of aneuploids induced in their germ cells were significantly increased.

[Requirements for the toxicological testing of new pesticides and agents for controlling biological processes]. / Anforderungen an die toxikologische Prüfung neuer Pflanzenschutzmittel und Mittel zur Steuerung biologischer Prozesse.

Growing amounts of pesticides and plant growth regulators are being used in our time and call for action to ensure safety for man and farm animals. Toxicological rules and requirements are discussed with reference to the legal provisions in the USSR, USA, and FRG. Specifications for toxicological assessment of new preparations have been prepared in the GDR and Poland and are described. Particular emphasis is laid on studies into acute, subacute or subchronic, and chronic toxicity and delayed consequences. Conclusions are suggested and steps discussed to decide tolerances for food and feedstuffs.