Plant Tissue Type Research Articles

Milkweed in agricultural field margins - A neonicotinoid exposure route for pollinators at multiple life stages

Neonicotinoid insecticides move from targeted crops to wildflowers located in adjacent field margins, acting as a potential exposure source for wild pollinators and insect species of conservation concern, including monarch butterflies. Monarchs rely on milkweed over multiple life stages, including as a host plant for eggs and a food source for both larvae (leaves) and adults (flowers). Milkweeds, which are closely associated with field margins, can contain neonicotinoid residues, but previous assessments are constrained to a single plant tissue type. In 2017 and 2018, we sampled milkweeds from 95 field margins adjacent to crop fields (corn, soybean, hay, wheat, and barley) in agricultural landscapes of eastern Ontario, Canada. Milkweeds were sampled during the flower blooming period and leaves and flower tissues were analysed. The neonicotinoids acetamiprid, clothianidin, thiamethoxam, and thiacloprid were detected. Maximum concentrations in leaf samples included 10.30 ng/g of clothianidin in 2017, and 24.4 ng/g of thiamethoxam in 2018. Clothianidin and thiamethoxam percent detections in flowers (72 % and 61 %, respectively) were significantly higher than detections in leaves (24 % and 31 %, respectively). Thiamethoxam concentrations were significantly higher in paired flower samples than leaf samples (median 0.33 ng/g vs <0.07 ng/g) while clothianidin concentrations also trended higher in flowers (median 0.18–0.55 ng/g vs <0.18 ng/g). Only thiamethoxam showed significant differences between years, and we found no effect of crop type, with hay, soybean and corn fields all yielding 50–56 % detections in leaves. We found significantly higher concentrations in older milkweed flowers than young flowers or leaves (medians 0.87 ng/g vs <0.18 ng/g and 0.45 ng/g vs <0.07 ng/g for clothianidin and thiamethoxam, respectively). Our results highlight the importance of considering variation in milkweed tissue type and age of flowers in neonicotinoid exposure risk assessments. Efforts to increase milkweed availability in agricultural landscapes should consider how exposure to neonicotinoids can be mitigated.

Vertical distribution and tissue selection of Helicoverpa zea (Lepidoptera: Noctuidae) adult oviposition and neonates on soybean with an indeterminate or determinate growth habit.

Helicoverpa zea (Boddie) is a polyphagous pest that can cause serious damage to crops, including soybeans (Glycine max L.). In soybeans with both determinate and indeterminate growth habits, H. zea larvae are more commonly found on leaves compared to blooms, stems, and pods. Past research demonstrated that H. zea adults tend to oviposit near the upper part of the plant canopy in soybeans with a determinate growth habit. However, ovipositional selection on soybeans with an indeterminate growth habit is unknown. We hypothesized that H. zea would oviposit more uniformly throughout the canopy on indeterminate soybean growth habits due to more diffuse reproductive tissue. We planted field and greenhouse experiments with varieties sharing a similar relative maturity (2 maturity group [MG] 5.2 varieties and 2 MG 5.4/5.5 varieties) but with different growth habits. To test oviposition selection, adult H. zea females were allowed to oviposit under field and caged conditions. We counted the number of H. zea eggs and neonates on each plant tissue type from each of 3 equal parts in the plant canopy: upper, middle, and lower. In both experiments, eggs and neonates were most common on leaves at the top of the plant regardless of soybean growth habit. Consequently, ovipositional selection is likely independent of reproductive tissue availability, and patterns of oviposition through the canopy are similar in growth habits. An improved understanding of H. zea ecology in soybeans relative to indeterminate growth habits may improve recommendations for managing this significant pest of soybean.

Ultrasound-Assisted Extraction of Bioactive Compounds from Broccoli By-Products.

The objective of this work was to gain insight into the operating conditions that affect the efficiency of ultrasound-assisted extraction (UAE) parameters to achieve the best recovery of bioactive compounds from broccoli leaf and floret byproducts. Therefore, total phenolic content (TPC) and the main sulfur bioactive compounds (sulforaphane (SFN) and glucosinolates (GLSs)) were assayed. Distilled water was used as solvent. For each byproduct type, solid/liquid ratio (1:25 and 2:25 g/mL), temperature (25, 40, and 55 °C), and extraction time (2.5, 5, 7.5, 10, 15, and 20 min) were the studied variables to optimize the UAE process by using a kinetic and a cubic regression model. TPC was 12.5-fold higher in broccoli leaves than in florets, while SFN was from 2.5- to 4.5-fold higher in florets regarding the leaf's extracts obtained from the same plants, their precursors (GLS) being in similar amounts for both plant tissues. The most efficient extraction conditions were at 25 °C, ratio 2:25, and during 15 or 20 min according to the target phytochemical to extract. In conclusion, the type of plant tissue and used ratio significantly influenced the extraction of bioactive compounds, the most efficient UAE parameters being those with lower energy consumption.

Biochemical and molecular responses of the ascorbate-glutathione cycle in wheat seedlings exposed to different forms of selenium

Biofortification aims to increase selenium (Se) concentration and bioavailability in edible parts of crops such as wheat (Triticum aestivum L.), resulting in increased concentration of Se in plants and/or soil. Higher Se concentrations can disturb protein structure and consequently influence glutathione (GSH) metabolism in plants which can affect antioxidative and other detoxification pathways. The aim of this study was to elucidate the impact of five different concentrations of selenate and selenite (0.4, 4, 20, 40 and 400 mg kg−1) on the ascorbate-glutathione cycle in wheat shoots and roots and to determine biochemical and molecular tissue-specific responses. Content of investigated metabolites, activities of detoxification enzymes and expression of their genes depended both on the chemical form and concentration of the applied Se, as well as on the type of plant tissue. The most pronounced changes in the expression level of genes involved in GSH metabolism were visible in wheat shoots at the highest concentrations of both forms of Se. Obtained results can serve as a basis for further research on Se toxicity and detoxification mechanisms in wheat. New insights into the Se impact on GSH metabolism could contribute to the further development of biofortification strategies.

Palmelloid Formation and Cell Aggregation Are Essential Mechanisms for High Light Tolerance in a Natural Strain of Chlamydomonas reinhardtii.

Photosynthetic organisms, such as higher plants and algae, require light to survive. However, an excessive amount of light can be harmful due to the production of reactive oxygen species (ROS), which cause cell damage and, if it is not effectively regulated, cell death. The study of plants' responses to light can aid in the development of methods to improve plants' growth and productivity. Due to the multicellular nature of plants, there may be variations in the results based on plant age and tissue type. Chlamydomonas reinhardtii, a unicellular green alga, has also been used as a model organism to study photosynthesis and photoprotection. Nonetheless, the majority of the research has been conducted with strains that have been consistently utilized in laboratories and originated from the same source. Despite the availability of many field isolates of this species, very few studies have compared the light responses of field isolates. This study examined the responses of two field isolates of Chlamydomonas to high light stress. The light-tolerant strain, CC-4414, managed reactive oxygen species (ROS) slightly better than the sensitive strain, CC-2344, did. The proteomic data of cells subjected to high light revealed cellular modifications of the light-tolerant strain toward membrane proteins. The morphology of cells under light stress revealed that this strain utilized the formation of palmelloid structures and cell aggregation to shield cells from excessive light. As indicated by proteome data, morphological modifications occur simultaneously with the increase in protein degradation and autophagy. By protecting cells from stress, cells are able to continue to upregulate ROS management mechanisms and prevent cell death. This is the first report of palmelloid formation in Chlamydomonas under high light stress.

Stress disorders of woody plants as a consequence of damage from high temperatures and fires

Plants are sessile organisms that are under the constant influence of the environmental conditions in which they grow. Any change in "inanimate" factors that have a significant impact on plant growth and development is collectively referred to as "abiotic stress". Extreme temperatures, especially in changed climatic conditions, are one of the most harmful abiotic factors, which cause heat stress in plants. The effects of high temperatures can be manifested through various morphological, physiological and genetic changes in the plant organism. Generally speaking, plants can be divided into three groups according to temperature requirements: psychrophilic plants, mesophilic plants and thermophilic plants. Most woody species belong to the group of mesophilic plants, which require temperatures between 10 and 30 °C for successful growth and development. As the temperature changes on a daily and seasonal basis in relation to the optimal range, certain changes occur in the plant organism that are necessary to maintain cell growth and homeostasis. Regardless of their ability to adapt to temperature oscillations, plants that have been exposed to temperatures above the optimal level for a long time can show symptoms of irreversible damage, which manifest as heat stress. Generally speaking, this type of stress is considered to occur when the temperature is 10- 15 °C higher than usual at some time of the year, and lasts long enough to cause irreversible damage or disturbances in plant growth and development. As the intensity, duration and degree of temperature change change, so do the various effects of heat stress on plants. In order to survive, plants must adapt to changes in environmental conditions through a specific response that depends on the physiology and morphology of a species. According to their level of tolerance to high temperatures, plants can be divided into three categories: heat-sensitive, relatively heat-sensitive, and heattolerant. The shape and strength of tolerance to high temperatures mostly depend on the plant species, tissue type and cells that are exposed to negative influences. The increase in ambient temperature can also jeopardize the productivity of agricultural crops and forest trees, which has been visible in recent decades in light of climate change and projections regarding the security of supply of the growing population on Earth. Injuries resulting from high temperatures during a fire can initiate a cascade of complex mechanisms that affect the physiology of trees after a fire. The discovery of exact physiological mechanisms and corresponding specific injuries that occur on individual trees, as well as in forest ecosystems, are the focus of intensive modern research. Recent studies have made critical strides in understanding the physiological processes in trees that manifest after fire injuries, and these injuries can affect the tree in combination with some other stressful conditions, such as drought and insect and pathogen attacks. The paper presents a conceptual framework that combines all these processes, their mutual interactions and possible responses, and puts these plant responses in the context of existing hypotheses about the impacts of specific disturbances on plants and ecosystems. By focusing on carbon and water as the main factors in the functioning of the plant organism, this paper presents cambium/phloem necrosis and xylem damage as the main effects of fire injuries. The resulting lack of carbon and hydraulic dysfunction of plants are associated with drought and insect attack. Assessing the precise relationships of the processes presented will be crucial to fully understanding how fires can affect tree functionality and will help improve fire risk assessment and predict tree mortality models. Knowledge of the physiological responses of trees is important for a better assessment of ecosystem dynamics after a fire and their interaction with climate disturbances, and especially taking into account the predicted increase in the frequency and intensity of fires.

Application of Data Modeling, Instrument Engineering and Nanomaterials in Selected Medid the Scientific Recinal Plant Tissue Culture

At present, most precious compounds are still obtained by plant cultivation such as ginsenosides, glycyrrhizic acid, and paclitaxel, which cannot be easily obtained by artificial synthesis. Plant tissue culture technology is the most commonly used biotechnology tool, which can be used for a variety of studies such as the production of natural compounds, functional gene research, plant micropropagation, plant breeding, and crop improvement. Tissue culture material is a basic and important part of this issue. The formation of different plant tissues and natural products is affected by growth conditions and endogenous substances. The accumulation of secondary metabolites are affected by plant tissue type, culture method, and environmental stress. Multi-domain technologies are developing rapidly, and they have made outstanding contributions to the application of plant tissue culture. The modes of action have their own characteristics, covering the whole process of plant tissue from the induction, culture, and production of natural secondary metabolites. This paper reviews the induction mechanism of different plant tissues and the application of multi-domain technologies such as artificial intelligence, biosensors, bioreactors, multi-omics monitoring, and nanomaterials in plant tissue culture and the production of secondary metabolites. This will help to improve the tissue culture technology of medicinal plants and increase the availability and the yield of natural metabolites.

THE INFLUENCE OF CLIMATIC CONDITIONS ON ACCUMULATION OF BIOLOGICALLY ACTIVE COM-POUNDS IN KOENIGIA WEYRICHII

Koenigia Weyrichii (F. Schmidt) T.M. Schust. et Reveal is a herbaceous perennial plant introduced to the Murmansk and Tomsk regions in the mid–twentieth century. This plant accumulates a sufficiently large amount of flavonoids, which makes it a promising source of biologically active compounds. The purpose of this study was to determine how different location and climatic conditions affect the content of total phenols, flavonoids, antioxidant and antiradical activity of K. Weyrichii ethanol extracts obtained from different plant organs in different phases of vegetation. Inflorescences, leaves of the upper and middle tiers of K. Weyrichii were collected in three places – in the districts of Apatity, Kirovsk (Kola Peninsula, Murmansk region) and Tomsk (Western Siberia, Tomsk region) during flowering and fruiting periods. For ethanol extracts, the total content of polyphenolic components in reaction with Folin-Chokalteu reagent, flavonoids in reaction with aluminum chloride, total antioxidant and antiradical activity determined by phosphomolybdate and DPPH methods, respectively, were determined. The results of ANOVA factor analysis showed that these parameters depend on the place of growth, the period of collection and the type of plant tissue. The higher average value of the accumulation of total polyphenols was observed in Kirovsk – 106.2 мг GAE/г (GAE is the equivalent of gallic acid), the lowest – in Tomsk: 86.1 мг GAE/г. The average value of flavonoid accumulation was higher in Apatity – 4.39 мг,RE/г (RE – equivalent of rutin), less in Tomsk – 3.12 мг RE/г. Lower temperatures, less precipitation, and longer daylight hours in Apatity and Kirovsk contributed to a greater accumulation of flavonoids compared to Tomsk. In the inflorescences during the mass flowering period, there was a greater accumulation of flavonoids and a greater antioxidant activity of extracts at all three sites. The obtained data can be used as a theoretical basis for the rational use of K. Weyrichii as a promising source of flavonoids.

Plant-Programmed Cell Death-Associated Genes Participation in Pinus sylvestris L. Trunk Tissue Formation.

Molecular genetic markers of various PCD (programmed cell death) variants during xylo- and phloemogenesis have been identified for the first time in Scots pine under lingonberry pine forest conditions in Northwest Russia (middle taiga subzone). PCD is a genetically determined process. Gene profiles of serine and cysteine proteases (endopeptidases), endonucleases, and metacaspases families are often considered markers of the final xylogenesis stage. In the present study, we examined the gene expression profiles of the BFN (bifunctional endonuclease) family-BFN, BFN1, BFN2, BFN3, and peptidase (cysteine endopeptidase, CEP and metacaspase, MC5) in the radial row, in addition to the vascular phloem and cambium (F1), differentiating xylem (F2), sapwood (SW), and transition zone during the active cambial growth period of uneven-aged pine trees (25-, 63- and 164-cambial age (c.a.) years old). We have shown that the expression patterns of the PCD-related genes did not depend on the cambial age but were largely determined by plant tissue type. In the radial row F1-F2-SW, we studied the activities of enzymes, including sucrose in metabolism (sucrose synthase, three forms of invertase); antioxidant system (AOS) enzymes (superoxide dismutase, catalase); and peroxidase andpolyphenol oxidase, which belonged to AOS enzymes and were involved in the synthesis of phenolic components of cell walls. The activity of the enzymes indicated that the trunk tissues of pine trees had varying metabolic status. Molecular genetic PCD regulation mechanisms during xylem vascular and mechanical element formation and parenchyma cells' PCD during the formation of Scots pine heartwood were discussed.

Rhizodeposition and litter decomposition of Phragmites australis play important roles in composition and properties of soil dissolved organic matter

The dynamics of composition and properties of dissolved organic matter in soil depend on plant carbon inputs and microbial degradation. However, uncertainties remain regarding the relative contributions of different plant carbon inputs sources, i.e., from litter decomposition versus rhizodeposits, to soil dissolved organic matter, which may limit the understanding of soil carbon dynamics. In this study, effects of plant carbon inputs from either rhizodeposition or litter (leaf, stem, rhizome, and root litter) decomposition on composition and optical properties of soil dissolved organic matter were estimated. Rhizodeposition and litter decomposition of P. australis had significant effects on soil dissolved organic matter, and its variation was mainly associated with the third fluorescent component (C3). Effects of rhizodeposition on soil dissolved organic matter were significantly altered by soil salinity, exhibiting increased chromophoric dissolved organic matter and fulvic acid C3 under saline conditions. Effects of litter decomposition on soil chemistry and dissolved organic matter varied greatly among plant tissues. Compared with rhizome and root, leaf and stem decomposed more thoroughly and significantly increased the contents of fulvic acid C3. This was supported by increased aromaticity associated with leaf inputs and increased plant-derived dissolved organic matter associated with stem and leaf inputs. These findings highlight the significant influence of rhizodeposition and litter decomposition on soil dissolved organic matter, and suggest that the roles of salinization and plant tissue type merit consideration in further studies on plant–soil carbon cycling.

Hot Water Treatment Causes Lasting Alteration to the Grapevine (Vitis vinifera L.) Mycobiome and Reduces Pathogenic Species Causing Grapevine Trunk Diseases.

The effective management of grapevine trunk diseases (GTDs) is an ongoing challenge. Hot water treatment (HWT) is an environmentally friendly and economically viable option; however, the short-term effects of HWT on grapevine (Vitis vinifera L.) health and production are not fully understood. The aim of this study was to compare the effects of HWT on plant growth and fungal community structure in nursery stock until plants were completely established in the field. We assessed eleven graft and three rootstock varieties from four local nurseries in a region of Catalonia (NE Spain) where GTDs are a serious threat. After treatment, the plants were left to grow under field conditions for two growing seasons. Metabarcoding of the ITS region was used to study the mycobiomes of plant graft unions and root collars. We also assessed the influence of plant physiological indicators in community composition. Hot water treatment caused lasting changes in GTD communities in both the root collar and graft union that were not always characterized as a reduction of GTD-related fungi. However, HWT reduced the relative abundance of some serious GTD-associated pathogens such as Cadophora luteo-olivacea in graft tissues, and Phaeomoniella chlamydospora and Neofusicoccum parvum in the root collar. Treatment had the greatest influence on the total and GTD-related fungal communities of Chardonnay and Xarel·lo, respectively. Total community variation was driven by treatment and nursery in rootstocks, whereas HWT most significantly affected the GTD community composition in R-110 rootstock. In conclusion, changes in fungal abundance were species-specific and mostly dependent on the plant tissue type; however, HWT did reduce plant biomass accumulation in the short-term.

ON THE FRUIT AND VEGETABLES PLANT CELL WALL HEMICELLULOSE COMPOUND STRUCTURE

Plant raw material biochemical characteristics may vary depending on it`s species, organ and tissue type and even cultivation facilities, and this dependence may discover a great field of interest for researches. These researches may result not only in fundamental information on plant biochemical development regularity, but in determination of plant potential as a raw material for biological active additives obtaining. The neutral oligo- and polysachharides of cell wall belonging to hemicelluloses have different structure depending on plant tissue type and plant species. The polysachharides isolating from plant raw material can be used in food technology as thickeners and sorbents (pectin, gums), so the structure determinating for different plant species can be useful in technological potential determination of studying plant raw material for food additives obtaining. The article presents the review on hemicelluloses structures and hemicelluloses complex researches for different types of fruit and berries raw material in purchase to estimate the availability of the raw plant material as a food additives source. Analyzed resources allows us to conclude that there is no visible regularity in hemicellulose complex of studied fruit and berry species, and all of these species can be a used as a sourse of polysachharides, excepts black currant because of high level of oligosachharides and sugar beet because of low hemicellulose yields. Gelling ability appears only in polysachharides.

Fungal Communities of Spring Barley from Seedling Emergence to Harvest During a Severe Puccinia hordei Epidemic.

All plant tissues from leaves, stems, and roots are hosting a wide diversity of fungal species. Our understanding of the assembly of this diversity of fungi during the plant growth cycle is limited. Here, we characterized the mycobiome of three spring barley cultivars grown in Zealand, Denmark, at weekly intervals during a growth season from seedling emergence to senescence and seed maturity. A notable proportion of members of the fungal communities were shared among different plant organs, but community dynamics were tissue-specific. A severe attack of Puccinia hordei occurring during the vegetative stage had profound effects on the mycobiome, and P. hordei biomass displaced that of other taxa. Plant tissue type was the most important factor determining the mycobiome, but also plant age was contributing significantly. Using a random forest model, we found that specific members of the mycobiome were responding differently to plant age, for instance, Olpidium and Articulospora in roots, Dioszegia and Sporobolomyces in leaves, Pyrenophora in stems, and Epicoccum in heads. A co-occurrence network analysis revealed complex interactions among fungal OTUs, and network connectivity was changing as per plant growth stage and plant tissue type. This study contributes to the understanding of assembly of fungal communities in cereals by providing a detailed description of fungal communities associated with barley. This knowledge will be vital for microbiome assisted plant health management and our study will serve as an important baseline for future efforts to harness microbiota in cereal health.

A Review of Bio-Role Fumigation&amp;apos;s in Plant Parasitic Nematode (PPNs) Control

Worldwide there are greater than 4,100 species of PPNs. The most common opponent of agricultural production is PPNs. Plant parasitic nematodes (PPN) cause substantial economic destruction to an extensive range of crops. Nematicide Chemicals are considered the furthermost operative method in reducing nematodes population. Increasing concern over chemical nematicides has increased interest in safe alternative methods to minimize these losses. This review focuses on the role of bio-fumigation against PPNs in sustainable agroecosystems. Bio-fumigation is a long-term approach for controlling diseases, nematodes, insects, and weeds in the soil. It was originally defined as the pest-controlling effect of decomposing Brassica tissues, but it was later broadened to include animal and plant leftovers. Glucosinolates are the principal active molecule responsible for the bio-fumigation process in various plants. Plant age and tissue type influence glucosinolate accumulation and myrosinase activity, which are influenced by environmental factors such as planting density and herbivory. Glucosinolates are sulphur-containing chemicals produced by the secondary metabolism of plants in the order Capparales, which includes the Brassicacea family among others. Natural antimicrobials and anti-carcinogenic agents, glucosinolates are well-known. Therefore, researchers should have to focus on environmentally save methods of plant parasitic nematode management like bio-fumigation. This biofumigation may be replace the fumigant nematicides for future.

Эффективный способ выделения ДНК для ПЦР-анализа из «балк-образцов» проростков

Forage annual and perennial grasses are the difficult subject for molecular and genetic studies because of the problem with obtaining qualitative genomic DNA for PCR, due of high content of proteins, polysaccharides and polyphenols. The known methods of DNA extraction or the numerous commercial kits allow isolating purified nucleic acids from the leaf tissue, but characterized by low efficiency at seedlings using. The modified method of DNA isolation, based on the SDS-extraction buffer (sodium dodecil sulfate), is presented in this study. Significant modifications were introduced in the reagents compound and the steps of procedure accordingly to used type of plant tissue and the result was positive at usage on the bulking samples, as well as on the individual genotypes (the only seedling). Reliability of this method and the functionality of the obtained DNA samples were tested in PCR with different molecular markers (SSR, SRAP and PawS) in researches on revealing of forage legume grasses DNA polymorphism. The general advantages of the proposed method are simplicity and effectiveness, the possibility to isolate qualitative DNA without toxic reagents application, as well as relatively low cost and availability of reagents. This method can be useful for studying the genetic biodiversity and for decision the different tasks, required the rapid analysis of large plant populations.

Glyphosate remains in forest plant tissues for a decade or more

Glyphosate-based herbicides are highly effective, non-selective, and broad-spectrum herbicides that have been used in British Columbia’s forest industry since the early 1980’s. Over this time, long-term persistence of glyphosate has not been measured, largely due to the inability to analyze glyphosate at low concentrations. Given the advancements in analytical techniques that are now available, we have extended the persistence curve of glyphosate to elucidate the actual length of time of persistence in northern British Columbia, rather than relying on estimations of persistence based on half-life curves that are quite often modelled from incomparable environments. We collected plant tissues from five forest understory perennial species growing in two distinct biogeoclimatic regions of northern BC to map out how glyphosate residue quantities change over time according to species, plant tissue type, and climate regime. We found that residues persisted for up to 12 years in some tissue types, and that root tissues generally retained glyphosate residues longer than shoot tissue types. We also found that samples from the colder, more northern biogeoclimatic zone investigated retained significantly higher levels of glyphosate for longer than samples collected from the warmer biogeoclimatic zone.

Laser Microdissection of Specific Stem-Base Tissue Types from Olive Microcuttings for Isolation of High-Quality RNA.

Simple SummaryOnly a small portion of the stem cells participate in the process of adventitious root formation and the cells/tissues types involved in this process is species-dependent. In olive, it is still unclear which type of cells acquire competence for rooting. Regardless, the entire stem nodal segment (containing a mixture of distinct cell types) continues to be used in studies related to the molecular mechanisms underlying this process. Laser microdissection (LM) technology has been applied to isolate specific tissue and cell types. However, it is difficult to find a standard LM protocol suitable for all plant species and cell types and, thus, LM procedures must be developed and optimized for each particular tissue. In this study, we aimed to evaluate the efficiency of a LM protocol in olive microcuttings stem-base samples. This work presents a simple, rapid and efficient LM procedure for harvesting specific tissue types used for further high-quality RNA isolation. This will encourage future cell type-specific transcriptomic studies, contributing at deciphering rooting-competent cells in olive stems and to better understand the molecular mechanisms underlying the process of adventitious root formation.Higher plants are composed of different tissue and cell types. Distinct cells host different biochemical and physiological processes which is reflected in differences in gene expression profiles, protein and metabolite levels. When omics are to be carried out, the information provided by a specific cell type can be diluted and/or masked when using a mixture of distinct cells. Thus, studies performed at the cell- and tissue-type level are gaining increasing interest. Laser microdissection (LM) technology has been used to isolate specific tissue and cell types. However, this technology faces some challenges depending on the plant species and tissue type under analysis. Here, we show for the first time a LM protocol that proved to be efficient for harvesting specific tissue types (phloem, cortex and epidermis) from olive stem nodal segments and obtaining RNA of high quality. This is important for future transcriptomic studies to identify rooting-competent cells. Here, nodal segments were flash-frozen in liquid nitrogen-cooled isopentane and cryosectioned. Albeit the lack of any fixatives used to preserve samples’ anatomy, cryosectioned sections showed tissues with high morphological integrity which was comparable with that obtained with the paraffin-embedding method. Cells from the phloem, cortex and epidermis could be easily distinguished and efficiently harvested by LM. Total RNA isolated from these tissues exhibited high quality with RNA Quality Numbers (determined by a Fragment Analyzer System) ranging between 8.1 and 9.9. This work presents a simple, rapid and efficient LM procedure for harvesting specific tissue types of olive stems and obtaining high-quality RNA.

Three new methods indicate that CO2 concentration affects plant respiration in the range relevant to global change.

Short-term responses of plant dark respiration to carbon dioxide concentration ([CO2]) in the range anticipated in the atmosphere with global change remain controversial, primarily because it is difficult to convincingly eliminate the many possible sources of experimental error in measurements of carbon dioxide or oxygen exchange rates. Plant dark respiration is a major component of the carbon balance of many ecosystems. In seedlings without senescent tissue, the rate of loss of dry mass during darkness indicates the rate of respiration. This method of measuring respiration was used to test for [CO2] effects on respiration in seedlings of three species with relatively large seeds. The time it took respiration to exhaust substrates and cause seedling death in darkness was used as an indicator of respiration rate in four other species with smaller seeds. The third method was measuring rates of CO2 exchange in excised petioles sealed in a cuvette submerged in water to prevent leaks. Petioles were utilized as the plant tissue type with the most reliable rates of respiration, for excised tissue. The rate of loss of dry mass in the dark decreased with increasing [CO2] in the range of 200-800 μmol mol-1 in all three large-seeded species. The seedling survival time in the dark increased with [CO2] in the same concentration range in all four of the smaller-seeded species. Respiration rates of excised petioles of several species also decreased over this [CO2] range. The data provide new evidence that the rate of dark respiration in plant tissue often decreases with increasing [CO2] in the 200-800 μmol mol-1 range.

Extraction of Alkaloids Using Ultrasound from Pulp and By-Products of Soursop Fruit (Annona muricata L.)

The main goal of this work was to measure the total alkaloid content (TALC) from pulp, peel, seed, and columella of soursop fruit (Annona muricata L.) by ultrasound-assisted extraction (UAE) and to obtain the best conditions of the UAE with the response surface methodology (RSM). We evaluated the effect of amplitude (40%, 70%, and 100%), time (5, 10, and 15 min) and pulse-cycles (0.4, 0.7, and 1 s) and compared the best UAE conditions of alkaloids with a conventional extraction (maceration). The structural characterization of the raw material with the highest TALC was developed using nuclear magnetic resonance (NMR) techniques [1H, 13C, heteronuclear single quantum correlation (HSQC), heteronuclear multiple bond correlation (HMBC), and homonuclear correlation spectroscopy (COSY)]. According to the RSM, the best conditions in the UAE for extracting alkaloids varied depending on the type of plant tissue. It took 5 min with an amplitude of 70% and pulse-cycles of 1, 0.4, and 1 s, respectively, to extract the highest TALC in peel, seed, and columella while the optimal conditions for extracting the largest amount of alkaloids from the pulp were obtained at 5 min in UAE with pulse-cycles of 0.55 s and 100% amplitude. The TALC was highest in the peel (7.48 mg/g), which was followed by the seed (2.31 mg/g), the pulp (1.20 mg/g), and the columella (0.79 mg/g) and was positively correlated (R2 = 0.98–0.88) with the predicted values. In addition, the extraction alkaloids from the peel, pulp, seed, and columella using the UAE was 56.31, 5.45, 3.06, and 2.96 times higher, respectively, than the extraction by maceration. The alkaloids identified in the peel have not been reported and were nornuciferin, assimilobin, anonaine, and isolaureline. This study showed that the soursop fruit peel can be a source of alkaloids and that UAE has an important potential for extracting these compounds.

The complete functional characterisation of the terpene synthase family in tomato.

Summary Analysis of the updated reference tomato genome found 34 full‐length TPS genes and 18 TPS pseudogenes.Biochemical analysis has now identified the catalytic activities of all enzymes encoded by the 34 TPS genes: one isoprene synthase, 10 exclusively or predominantly monoterpene synthases, 17 sesquiterpene synthases and six diterpene synthases. Among the monoterpene and sesquiterpene and diterpene synthases, some use trans‐prenyl diphosphates, some use cis‐prenyl diphosphates and some use both. The isoprene synthase is cytosolic; six monoterpene synthases are plastidic, and four are cytosolic; the sesquiterpene synthases are almost all cytosolic, with the exception of one found in the mitochondria; and three diterpene synthases are found in the plastids, one in the cytosol and two in the mitochondria.New trans‐prenyltransferases (TPTs) were characterised; together with previously characterised TPTs and cis‐prenyltransferases (CPTs), tomato plants can make all cis and trans C10, C15 and C20 prenyl diphosphates. Every type of plant tissue examined expresses some TPS genes and some TPTs and CPTs.Phylogenetic comparison of the TPS genes from tomato and Arabidopsis shows expansions in each clade of the TPS gene family in each lineage (and inferred losses), accompanied by changes in subcellular localisations and substrate specificities.