Characteristics of Three Organic Fertilizers and Their Influence on the Mobility of Cadmium and Arsenic in a Soil-Rice (Oryza Sativa L.) System

The properties and effects of organic fertilizers are different, including the ability to improve soil fertility and the potential of stabilizing heavy metals in soils that have not been explored in depth. In this study, three organic fertilizers from different raw materials were characterized and evaluated. The mushroom residue organic fertilizer (MO) had higher C, H, and O contents and more functional groups (-OH, C-H, and C=O), and its application significantly increased pH (1.00~1.32 units), organic matter (OM) content (26.58%~69.11%) and cation exchange capacity (CEC) (31.52%~39.91%) of soil. MO treatment also reduced the toxicity characteristic leaching procedure (TCLP)-Cd (24.21%) and TCLP-As (18.44%) concentration in the soil. That inhibited the mobilization of Cd and As from soil to plant, especially to plant shoots, and positively affected the plant growth and biomass. Redundancy analysis (RDA) showed that 40.09 % of total plant variation was related to soil properties (pH, OM, and CEC). Furthermore, the heavy metal risk assessment for all organic fertilizers was at safe levels. This study provides a valuable reference for the selection of organic fertilizers. Besides, it recommends organic fertilizers as economic and multi-effect amendments with safe use and provides a new option for the ‘simultaneous production and remediation’ of farmlands with low pollution.

Bioactive compounds and antiradical activity of propolis from scaptotrigona bipunctata e scaptotrigona depilis / Compostos bioativos e atividade antiradical da própolis de scaptotrigona bipunctata e scaptotrigona depilis

Propolis is a viscous substance produced and collected from plant shoots or exudates by worker bees. This study aimed to identify phenolic compounds, carotenoids, volatile compounds, and antiradical activity of propolis obtained from two stingless bees (SB), Scaptotrigona bipunctata (Tubuna) and Scaptotrigona depilis (Canudo), all native from Rio Grande do Sul. The two propolis showed a similar qualitative composition, but with quantitative differences. Catechin was the major phenolic compound found in propolis from S. bipuncata and S. depilis. The propolis from S. depilis showed a higher concentration of carotenoids, mainly lutein. The α-pinene was the volatile compound found in greater concentration in the two propolis.

The effect of carbon dioxide on the production of potato minitubers under aeroponic cultivation

The paper presents data on the effect of additional top dressing of potato plants with CO2 at a concentration of 2500 ppm cultivated in aeroponic plants. It was found that the increased concentration of CO2 provides better development of plant shoots (128.6%) and the root system (120.1%) relative to the control: a larger yield (123.7%) with a larger fraction of minicubes is formed, and the number of plants capable of producing 1100-1600 g of minicubes during the cultivation period increases. Additional feeding of CO2 at a concentration of 2500 ppm leads to an increase in the mass of plants, which occurs not due to increased hydration of tissues, but due to the accumulation of dry substances.

PHENOLIC COMPOUNDS OF CONIFEROUS TREES

The paper discusses the classification, structure and properties of natural phenolic compounds found in conifers wood species of Russia. The reasons for the variety of detected phenolic compounds (more than 2000) are considered, including the type and conditions of plant growth, environmental factors, as well as methods for extraction of substances. Coniferous extractives include monomeric, dimeric and polymeric phenolic compounds in bound and free form, and their content differs significantly for various species and parts of a woody plant. Depending on the polarity of the solvent used (water, petroleum ether, dimethyl ether, ethyl acetate, acetone, etc.), the yield, chemical composition and structure of the extracted phenolic compound change. It was shown that bark extracts of Larch and Fir contain the most phenolic acids and extractive substances than Pine, Cedar and Spruce, while the content of polar substances is higher in needles, and non- polar substances in plant shoots. Phenolic compounds are secondary plant metabolites, exhibiting fungicidal, virucidal and strong antioxidant effects, that make them a valuable basis for the creation of drugs.

Features of seasonal growth of Arundo donax var. versicolor Mill. (Stokes) in the conditions of the M. M. Gryshko National Botanical Garden of the National Academy of Sciences of Ukraine

Purpose. To define of phenological and morphological features of A. donax var. versicolor growth during the introduction in the M. M. Gryshko National Botanical Garden of the National Academy of Sciences of Ukraine (NBG). Methods. The object of research was the plants of A. donax var. versicolor in the collection of ornamental grasses of the department of flower and ornamental plants of NBG. The plants were grown on a sunny experimental area during 2014–2020. Since under NBG conditions, A. donax var. versicolor did not enter the flowering phase, the beginning of the phases of spring regrowth, leaf unfolding, and the end of the growing season were recorded. Morphometric parameters and shoot-forming ability were investigated for 3–5 years of cultivation. Results. The beginning and duration of the phases of shoot spring regrowth and the unfolding of leaves of A. donax var. versicolor as well as their dependence on the sum of effective temperatures was established. Thus, spring regrowth begins with renewal buds on May 11 ± 5 days at the effective temperature sums of 226.6 ± 19.7 °С. The phase of leaf development in plants occurred on May 20 ± 7 days. The effective temperature sum at the beginning of this phase was 309.45 ± 11.66 °C. The productivity of shoot formation (1.6 ± 0.3 shoot per plant) under the conditions of introduction was determined. Conclusions. A. donax var. versicolor plants did not have a full cycle of seasonal development in the conditions of the NBG. Plants formed vegetative monocyclic shoots 240–260 cm tall. The duration of their vegetation was 182–189 days. The optimal period for the growth of the ground mass of plants fell on July-August. During this period, the leaves were quickly formed, the number of which was 28.8 ± 6.68 on the shoot. The correlation between the rate of accumulation of effective temperatures and the rate of regrowth of plant shoots was recorded.

Belowground allocation and dynamics of recently fixed plant carbon in a California annual grassland soil

Plant roots and the organisms that surround them are a primary source for stabilized organic C, particularly in grassland soils, which have a large capacity to store organic carbon belowground. To quantify the flow and fate of plant fixed carbon (C) in a Northern California annual grassland, we tracked plant carbon from a five-day 13CO2 pulse field labeling for the following two years. Soil and plant samples were collected immediately after the pulse labeling, and again at three days, four weeks, six months, one year, and two years. Soil organic matter was fractionated using a sodium polytungstate density gradient to separate the free-light fraction (FLF), occluded-light fraction (OLF), and heavy fraction (HF). Using isotope ratio mass spectrometry, we measured 13C enrichment and total C content for plant shoots, roots, soil, soil dissolved organic carbon (DOC), and the FLF, OLF, and HF. The HF was further analyzed by solid state 13C NMR spectroscopy. At the end of the labeling period, the largest amount of 13C was recovered in plant shoots (60%), but a substantial amount (40%) was already found belowground in roots, soil, and soil DOC. Density fractionation of 4-week soil samples (from which living roots were removed) indicated that the highest isotope enrichment was in the mineral-rich heavy fraction, with similar enrichment of the FLF and OLF. At the 6-month sampling, after the dry summer period during which plants senesced and died, the amount of label in the FLF increased such that it was equal to that in the HF. By the 1-year sampling, 13C in the FLF had declined substantially and continued to decline by the 2-year sampling. 13C recovery in the OLF and HF, however, was qualitatively stable between sampling times. By the end of the 2-year experiment, 69% of remaining label was in the HF, 18% in the FLF and 13% in the OLF. While the total 13C content of the HF did not change significantly from the 4-week to the 2-year sample time, 13C NMR spectroscopic analysis of spring HF samples from 2018, 2019, and 2020 suggests that the relative proportion of aliphatic/alkyl functional groups declined in the newly formed SOC over the 2-year period. Simultaneously, aromatic and carbonyl functional groups increased, and the proportion of carbohydrate groups remained relatively constant. In summary, our results indicate that initial associations between minerals and root-derived organic matter are significant and form rapidly; by 4 weeks, a substantial amount (17%) of the total plant-derived 13C had become associated with the heavy fraction (HF) of soil. While the majority of annual C input cycles rapidly (<2-year timescale), a sizeable proportion (~12% of the original inputs) persisted for 2 years.

Hydroponic Phytoremediation of Ni, Co, and Pb by Iris Sibirica L.

Heavy metal pollution in mine wastelands is quite severe. Iris sibirica L., an emergent wetland plant, is characterized by an ability to survive under high stress of heavy metals. This study aimed to explore the phytoremediation ability of nickel (Ni), cobalt (Co), and lead (Pb) by Iris sibirica L. under hydroponic conditions. A series of tests were conducted at different metal stress conditions to evaluate the phytoextraction and tolerance of Iris sibirica L. The concentrations of Ni, Co, and Pb in plant shoots reached their highest values in 500 mg L−1 treatments, where they were 6.55%, 23.64%, and 79.24% higher than those in 300 mg L−1, respectively. The same concentrations in roots also reached their peak in 500 mg L−1 treatments, where they were 5.52%, 33.02%, and 70.15% higher than those in 300 mg L−1, respectively. Bioconcentration factors (BCF) for Ni, Co, and Pb revealed the phytoextraction ability of Iris sibirica L., and the translocation factors (TCF) showed that Ni may be most easily translocated in the plant, followed by Co and Pb. This study indicates that, compared with Ni and Co, Iris sibirica L. is more suitable for the phytoremediation of Pb-contaminated metal mine wastelands.

Metabolic profiling, in vitro propagation, and genetic assessment of the endangered rare plant Anarrhinum pubescens

Background Anarrhinum pubescens Fresen. (Plantaginaceae) is a rare plant, endemic to the Saint Catherine area, of South Sinai, Egypt. Earlier studies have reported the isolation of cytotoxic and anti-cholinesterase iridoid glucosides from the aerial parts of the plant. The present study aimed to investigate the chemical profiling of the wild plant shoots as well as establish efficient protocols for in vitro plant regeneration and proliferation with further assessment of the genetic stability of the in vitro regenerated plants. Results Twenty-seven metabolites have been identified in wild plant shoots using the Nuclear Magnetic Resonance (NMR) spectroscopy. The metabolites include alkaloids, amino acids, carbohydrates, organic acids, vitamins, and a phenol. In vitro propagation of the plant was carried out through nodal cutting-micropropagation and leaf segment-direct organogenesis. The best results were obtained when nodal cutting explants were cultured on Murashige and Skoog medium with Gamborg B5 vitamins supplemented with 6-benzylaminopurine (BAP) (1.0 mg/L) and naphthaleneacetic acid (NAA) (0.05 mg/L), which gave a shoot formation capacity of 100% and a mean number of shoots of 27.67 ± 1.4/explant. These shoots were successfully rooted and transferred to the greenhouse and the survival rate was 75%. Genetic fidelity evaluation of the micropropagated clones was carried out using random amplified polymorphic DNA (RAPD) and inter simple sequence repeat (ISSR) molecular markers. Jaccard’s similarity coefficient indicated a similarity as high as 98% and 95% from RAPD and ISSR markers, respectively. Conclusions This study provides the chemical profiling of the aerial part of Anarrhinum pubescens. Moreover, in vitro regeneration through different tissue culture techniques has been established for mass propagation of the plant, and the genetic fidelity of the in vitro regenerated plants was confirmed as well. Our work on the in vitro propagation of A. pubescens will be helpful in ex situ conservation and identification of bioactive metabolites.

An automated system for trace gas flux measurements from plant foliage and other plant compartments

Plant shoots can act as sources or sinks of trace gases including methane and nitrous oxide. Accurate measurements of these trace gas fluxes require enclosing of shoots in closed non-steady-state chambers. Due to plant physiological activity, this type of enclosure, however, leads to CO2 depletion in the enclosed air volume, condensation of transpired water, and warming of the enclosures exposed to sunlight, all of which may bias the flux measurements. Here, we present ShoTGa-FluMS (SHOot Trace Gas FLUx Measurement System), a novel measurement system designed for continuous and automated measurements of trace gas and volatile organic compound (VOC) fluxes from plant shoots. The system uses transparent shoot enclosures equipped with Peltier cooling elements and automatically replaces fixated CO2 and removes transpired water from the enclosure. The system is designed for measuring trace gas fluxes over extended periods, capturing diurnal and seasonal variations, and linking trace gas exchange to plant physiological functioning and environmental drivers. Initial measurements show daytime CH4 emissions of two pine shoots of 0.056 and 0.089 nmol per gram of foliage dry weight (d.w.) per hour or 7.80 and 13.1 nmolm-2h-1. Simultaneously measured CO2 uptake rates were 9.2 and 7.6 mmolm-2h-1, and transpiration rates were 1.24 and 0.90 molm-2h-1. Concurrent measurement of VOC emissions demonstrated that potential effects of spectral interferences on CH4 flux measurements were at least 10-fold smaller than the measured CH4 fluxes. Overall, this new system solves multiple technical problems that have so far prevented automated plant shoot trace gas flux measurements and holds the potential for providing important new insights into the role of plant foliage in the global CH4 and N2O cycles.