Chemical Characterization and Phytotoxic Effects of the Aerial Parts of Ruzigrass (Urochloa ruziziensis).

Studies of the phytotoxic effects between plants can be a crucial tool in the discovery of innovative compounds with herbicide potential. In this sense, we can highlight ruzigrass (Urochloa ruziziensis), which is traditionally used in the crop rotation system in order to reduce weed emergence. The aim of this work was to characterize the secondary metabolites of ruzigrass and to evaluate its phytotoxic effects. In total, eight compounds were isolated: friedelin, oleanolic acid, α-amyrin, 1-dehydrodiosgenone, sitosterol and stigmasterol glycosides, tricin and p-coumaric acid. Phytotoxic effects of the crude methanolic extract and fractions of ruzigrass were assessed using germination rate, initial seedling growth, and biomass of Bidens pilosa, Euphorbia heterophylla and Ipomoea grandifolia. Chemometric analysis discriminated the weed species into three groups, and B. pilosa was the most affected by fractions of ruzigrass. The phytotoxic activities of 1-dehydrodiosgenone, tricin, and p-coumaric acid are also reported, and p-coumaric acid and 1-dehydrodiosgenone were active against B. pilosa.

Foliar Glyphosate Treatment Alters Transcript and Hormone Profiles in Crown Buds of Leafy Spurge and Induces Dwarfed and Bushy Phenotypes throughout its Perennial Lifecycle.

Leafy spurge ( L.) is an invasive weed of North America and its perennial nature attributed to underground adventitious buds (UABs) that undergo seasonal cycles of para-, endo-, and ecodormancy. Recommended rates of glyphosate (∼1 kg ha) destroy aboveground shoots but plants still regenerate vegetatively; therefore, it is considered glyphosate-tolerant. However, foliar application of glyphosate at higher rates (2.2-6.7 kg ha) causes sublethal effects that induce UABs to produce stunted, bushy phenotypes. We investigated the effects of glyphosate treatment (±2.24 kg ha) on vegetative growth, phytohormone, and transcript profiles in UABs under controlled environments during one simulated seasonal cycle. Because shoots derived from UABs of foliar glyphosate-treated plants produced stunted, bushy phenotypes, we could not directly determine if these UABs transitioned through seasonally induced endo- and ecodormancy. However, transcript abundance for leafy spurge dormancy marker genes and principal component analyses suggested that UABs of foliar glyphosate-treated plants transitioned through endo- and ecodormancy. Glyphosate treatment increased shikimate abundance in UABs 7 d after treatment; however, the abundance of shikimate gradually decreased as UABs transitioned through endo- and ecodormancy. The dissipation of shikimate over time suggests that glyphosate's target site was no longer affected, but these changes did not reverse the altered phenotypes observed from UABs of foliar glyphosate-treated leafy spurge. Transcript profiles further indicated that foliar glyphosate treatment significantly affected phytohormone biosynthesis and signaling, particularly auxin transport; gibberellic acid, abscisic acid and jasmonic acid biosynthesis; ethylene responses; and detoxification and cell cycle processes in UABs. These results correlated well with the available phytohormone profiles and altered phenotypes.

Plant growth promotion by inoculation with selected bacterial strains versus mineral soil supplements.

In the process of remediation of mine sites, the establishment of a vegetation cover is one of the most important tasks. This study tests two different approaches to manipulate soil properties in order to facilitate plant growth. Mine waste from Ingurtosu, Sardinia, Italy rich in silt, clay, and heavy metals like Cd, Cu, and Zn was used in a series of greenhouse experiments. Bacteria with putative beneficial properties for plant growth were isolated from this substrate, propagated and consortia of ten strains were used to inoculate the substrate. Alternatively, sand and volcanic clay were added. On these treated and untreated soils, seeds of Helianthus annuus, of the native Euphorbia pithyusa, and of the grasses Agrostis capillaris, Deschampsia flexuosa and Festuca rubra were germinated, and the growth of the seedlings was monitored. The added bacteria established well under all experimental conditions and reduced the extractability of most metals. In association with H. annuus, E. pithyusa and D. flexuosa bacteria improved microbial activity and functional diversity of the original soil. Their effect on plant growth, however, was ambiguous and usually negative. The addition of sand and volcanic clay, on the other hand, had a positive effect on all plant species except E. pithyusa. Especially the grasses experienced a significant benefit. The effects of a double treatment with both bacteria and sand and volcanic clay were rather negative. It is concluded that the addition of mechanical support has great potential to boost revegetation of mining sites though it is comparatively expensive. The possibilities offered by the inoculation of bacteria, on the other hand, appear rather limited.

Euphorbia characias as bioenergy crop: a study of variations in energy value components according to phenology and water status.

Euphorbia characias has drawn much attention as a potential bioenergy crop given its considerable amount of latex, rich in hydrocarbon-like compounds, and its ability to grow in large areas of semiarid lands. Compositions of major constituents with an energy value have been determined for the three phenological stages of this plant (preflowering, flowering, and postflowering) and different irrigation treatments. Metabolites from both nonpolar and polar extracts have been identified and quantified by GC-MS, GC-FID, HPLC-ELSD, and UPLC-PDA-MS. The results highlight that the end of the flowering period is the optimal harvesting time to maximize the yields of E. characias as a potential energy crop. The total water requirements to obtain the maximum yields of hexane- and methanol-extractables were determined for its annual development cycle.

Authentication of the 31 species of Toxic and Potent Chinese Materia Medica (T/PCMM) by microscopic technique, part 2: Three species of seed T/PCMM.

Toxic and Potent Chinese Materia Medica (T/PCMM) are being used more and more in the treatment of various diseases. In view of their toxic side effects and to ensure their safe use, accurate and reliable authentication is indispensable. However, identifying characteristics of T/PCMM are seldom reported, even though modern microscopy can provide ample, unique identifying characteristics from cells found in transverse sections and powders. In particular, no systematic authentication studies on seed T/PCMM have been conducted. In the course of our study on 31 T/PCMM originating from plants, animals, minerals, and secreta, an accurate and convenient method, based on microscopic techniques, has been developed and reported for the authentication of animal T/PCMM. The present study deals with detailed investigations on three species of seed T/PCMM, namely Semen Hyoscyami (Hyoscyamus niger L.), Semen Euphorbiae (Euphorbia lathyris L.), and Semen Strychni (Strychnos nux-vomica L.). The macroscopic characters are here described in detail, and the microscopic characters were conclusively determined by common and polarized light microscopy. Results showed that these three T/PCMM can be easily identified by the present method even when powdered and combined. Thus, the microscopic method is applicable for authentication of the earlier three T/PCMM, and the morphological and microscopic characteristics described here are proposed as parameters to establish the authenticity of these three T/PCMM.

[Effects of intercropping peanut with medicinal plants on soil microbial community].

With pot experiment, this paper studied the quantitative variations of bacteria, actinomyces, mould and yeast in soils of peanut intercropped with medicinal plants, aimed to test if such an intercropping pattern could remove the obstacles of peanut's continuous cropping. The results showed that Atractylodes lancea and Euphorbia pekinensis had the strongest inhibitory effect on mould. Compared with CK (mono-cropping peanut), the CFU of mould in the treatments intercropped with A. lancea and E. pekinensis was decreased by 53.87% and 29.59%, respectively during flowering-pegging stage of peanut, but increased after harvesting, which was in favor of substance circulation and nutrient returning. The CFU of bacteria in treatments intercropped with A. lancea, E. pekinensis and Pinellia ternate was all increased, and that of yeast in all five intercropping treatments was increased during the flowering-pegging stage of peanut. No familiar pathogens were found in the treatments intercropped with A. lancea, E. pekinensis and Diosoren zingiberebsis. Peanut intercropped with medicinal plants could regulate soil microbial community effectively.