Bark Parenchyma Research Articles

Anatomical structure of vegetative organs of Artichoke Green gold variety (in medium saline soil conditions)

For the first time, the anatomical structure of the vegetative organs of Artichoke Green gold variety, grown in medium salinity area of Bukhara region, has been studied. The following adaptive features were revealed: xeromorphic and mesoxeromorphic characters appeared, i.e., the size of leaf epidermis cells decreased, the number of stomata increased, the bark parenchyma of the stem thickened, the diameter and number of conducting tubes increased, and lignification increased. Changes in plant organs are not only related to their systematic condition, but also to the features of adaptation to living conditions in the process of evolution. Therefore, it can be used as important diagnostic signs in the study of the anatomical structure of plants to solve some problems in systematics, ecology, and morphology.

Pharmacognostic study of Catharanthus roseus (L.) G. Don, growing in Uzbekistan

In the article, the morpho-anatomical structure of the leaf and stem of Catharanthus roseus species distributed in the local conditions of Uzbekistan was studied, and it was determined that biologically active substances are found in the leaf mesophyll and bark parenchyma of the stem. The following diagnostic characters were determined: in the leaf – dorsiventral type of leaf mesophyll; thick-walled outer walls of the epidermis; amphistomatic leaves; not submerged stomata; chlorophyll-bearing palisade and spongy parenchyma; closed collateral type of conduction bundles; the presence of numerous idioblasts; in the stem there is a more lignified, non-tufted type of structure; libriform extensive; radial rays elongated and short; phloem is extensive, located between the crustal parenchyma and the libriform; the core is not wide, represented by large and small round-oval, thin-walled parenchyma cells containing hydrocyte cells and numerous laticifers. The content of moisture, ash, extractives extracted by heteropolar extractants was also studied, determined by pharmacopoeial methods to establish authenticity and prepare draft regulatory documentation for plant raw materials.

Changes in the Shoot Apical Meristem with Decrease in Illumination within the Crown of <i>Pseudotsuga menziesii</i> (Pinaceae) Introduced in St. Petersburg

Abstract—In Pseudotsuga menziesii Mirb. Franco introduced in St. Petersburg, the changes in the apical meristem morphogenesis during the formation of a short bud shoot with covering scales and meristematic primordium of shoot with needles, under the decrease in illumination within the crown were studied. Terminal 1–4-year-old shoots of the third-order branches in the lower part of the crown with a relative light availability (RLA) in the range of 23.9–18.3% perform full annual cycle of morphogenesis of the shoot apical meristem. Before each stage of morphogenesis, the apical meristem performs independent volume growth associated with the formation of mother groups of phytomer cells of covering scales and needles in the peripheral meristem. With RLA reducing to 15.1–15.4%, in terminal 5–6-year-old shoots over the growing season, the apical meristem performs only formation of a short bud shoot with covering scales and stops volume growth. This is because in the vascular bundles of the stele of the short bud stem, the sieve cells of the phloem are not formed, and the xylem part is poorly developed. The direct contact of the apex with the stele of the bud stem is blocked by procambium bundles, since their cells are differentiated and crystalline cellulose is accumulated in the cell walls. The cell walls of the bark parenchyma of the short bud stem contains significantly less birefringent inclusions, and only single small resin receptacles.

Morpho-Anatomical Features of Artemisia szowitziana (Besser) Grossh., 1934

The performed anatomical studies were conducted in accordance with the generally accepted methodology. The research materials (leaf, stem, root) were taken in all morpho-physiological development phases. As a result of the conducted morpho-anatomical research, a number of secret characteristics of A. szowitziana species were determined. A. szowitziana is a perennial, 50-60 cm or more tall, with oblong leaves. Fruiting pods are numerous, erect and branching slightly above the middle. The leaves of the lower stem are stalked, 2.5-3.5 cm long. Middle stem leaves are sessile. The mesophyll leaves are amphistomatic, isolateral-palisade type, the upper and lower epidermis contains small-celled palisade tissue. The thickened epidermal cells of the stem have 2-3 layers of collenchyma, homogeneous, polygonal and thin-walled bark parenchyma. The rhizodermis roots are covered with a single layer rhizodermis, 35-45 μm thick. Underneath the rhizodermis is a single-layered exoderm, 5-6 layered bark parenchyma, endoderm and pericycle. Since there is little humidity in summer and autumn in arid zones, the root develops very intensively in the humid period. As a result of the conducted research, it was determined that the species A. szovitsiana has the nature of adaptation to the environment, which is one of the structural characteristics of the general genus.

Anatomical structure of the Alhagi pseudalhagi stem

The present research focuses on studying the anatomical structure of annual shoots of Alhagi pseudalhagi, growing in the Karakum Desert in Turkmenistan. The Camelthorn plays a huge role in the desert biogeocenosis stability, restrains the advance of sand dunes, and is the main component of the country’s natural pastures. The non-tufted type of structure of Alhagi pseudalhagi offshoots was established in the work; the degree of development of the photosynthetic bark parenchyma of the stem was identified. Diagnostic features of the offshoots were determined - the presence of a two-layer epidermis, unicellular receptacles, a continuous ring of conductive tissues, and a filled core of the stem. The nature of the distribution of reservoirs in the stem and the degree of development of mechanical and conductive elements in wood and bast are considered. The results of the study can be used in further studies of the Alhagi genus in the field of botany, physiology, ecology of desert biogeocenoses.

Structural features of the bark in young stems of Betula ermanii Cham. in the conditions of Yuzhno-Sakhalinsky mud volcano (Sakhalin Island)

In the present paper, the results of the study of the structural peculiarities of Betula ermanii growing in the setting of the Yuzhno-Sakhalinsky mud volcano are presented. A statistical analysis of the structural parameters of young stem bark has been conducted, which has made it possible to distinguish features dependent on extreme environmental conditions. Parameters of young stem bark have been elicited, which have higher than normal values: the thickness of periderm and phellem, the diameter and length of sieve tube elements, the specific number of crystals in bark parenchyma, the specific area of sclerenchyma in the bark. The structural response of the young stem bark of Betula ermanii is likely to have an adaptive nature.

Rapid and complete removal of guayule (Parthenium argentatum) leaves by cryodefoliation, and freeze and thaw induction of rubber particle coagulation

Production of natural rubber (NR), a vital natural resource for modern economies, currently is completely dependent upon tropical cultivation of the Para rubber tree (Hevea brasiliensis, Müll. Arg). One promising source of alternative rubber is guayule (Parthenium argentatum, Gray), which is currently being developed as an alternative source of NR. Guayule rubber accumulates as rubber particles in bark parenchyma and can be extracted in the form of latex by homogenizing the bark and then separating the latex from the non-latex components by centrifugation. Latex separation and purification processes are significantly hindered by fine solids from the co-homogenized leaves. Therefore, complete removal of leaves before homogenization is highly desired. However, guayule leaves do not naturally abscise and chemical defoliants cannot be utilized since these dehydrate the shrub and coagulate the latex, and physical leaf removal processes are tedious or inefficient. We demonstrate that liquid nitrogen can be used to embrittle the leaves without freezing the bark parenchyma, completely removing the leaves with a single physical blow, and then the defoliated branches can be homogenized with no loss of latex-containing bark and no leaf contamination. Under longer freezing times, rubber coagulation occurred in partially frozen tissue and during slow thawing. Furthermore, we demonstrate that the rubber coagulation, which occurs when guayule branches are frozen through and thawed before homogenization, can be avoided by rapid homogenization of the flash frozen branches in ambient temperature aqueous extraction buffer.

Production and Properties of Yulex® - The Natural Solution to Latex Allergy

Abstract Natural rubber is an irreplaceable raw material vital to industry, transportation, medicine and defense, largely produced from clonal plantations of Hevea brasiliensis in Southeast Asia. Additional rubber-producing crops are greatly desired to increase biodiversity, protect supplies, and provide a safe alternative for people suffering from Type I latex protein allergy. Basic and applied research approaches were used to make the production of latex (Yulex® latex) from Parthenium argentatum (guayule) a commercial reality. In contrast to Hevea brasiliensis, from which rubber latex is tapped by hand from laticifers, guayule latex rubber is contained within individual bark parenchyma cells. Processing involves disrupting these cells to release the rubber particles, and then purifying the latex. As in the Hevea industry, latex concentration can be achieved by centrifugation and/or by creaming agents. An artificially produced guayule natural rubber latex is then produced, under the material name of “Yulex® latex”. The Yulex Pilot Plant has been constructed, optimized and automated, and extracts then purifies latex from guayule shrub without detectable losses. The natural rubber polymers in guayule latex are high molecular weight and products made from this material have the desired high performance properties. Because guayule latex contains very little protein, all of which is hydrophobic and bound to the rubber phase, and because none of the protein cross-reacts with Type I latex allergy to Hevea latex products, its use is initially aimed towards the high-value medical products marketplace. Clinical and performance trials continue to ensure that guayule processing provides a safe, high performance, non-allergenic natural rubber latex that is safe for human use.

(453) Effect of Drought Stress on Growth and Secondary Compound Production in Greenhouse-grown Guayule

As a native of the Chihuahuan desert, guayule (Partheniumargentatum Gray) has a history of dealing with low water availability. Agronomic studies have shown that increasing irrigation increases overall rubber yields, but decreases rubber concentration per plant. As water availability is an important factor in agricultural production, this study was conducted to examine how drought affects plant growth and secondary compound distribution throughout the plant. One-year-old guayule plants were subjected to water stress from June through August, in 2003 and 2004. The well-watered treatment was irrigated daily, and the drought-stressed plants were irrigated when the soil water potential reached 6 (0.6) or 3 (0.3) bars (megapascals) in 2003 and 2004, respectively. Plant growth was monitored by measuring height, width, and stem diameter. Fresh weight of shoots and roots was recorded at harvest, and a subset of plants were defoliated and used to determine leaf weight and area. Resin and rubber were extracted from dried and ground plant samples. Growth, leaf weight, and leaf to stem ratio were decreased in the drought-stressed plants compared to the well-watered plants. Rubber concentration, but not resin concentration, was higher in the drought-stressed plants. There were no significant differences in resin and rubber concentration in the leaves and roots of the different treatments; however, they were both higher in the stems of the drought-stressed plants. In guayule, rubber is deposited mainly in the bark parenchyma of the stems. The drought-stressed plants had a greater contribution of stem biomass to overall biomass and a reduced stem diameter with higher bark to wood ratio, which could account for the higher rubber concentration in the drought-stressed plants.

Cloning and expression of a dehydrin-like protein from Pistacia vera L.

A full-length dehydrin-like cDNA clone was obtained from a Pistacia vera L. cDNA library. The clone was sequenced and it was found that the deduced protein consists of 230 amino acids with a molecular weight of 25.87 kDa. The glycine rich protein is highly hydrophilic, contains 47.4% charged amino acids and belongs to the Kn-type of dehydrins. It comprises five repetitive units, each containing the K-segment diagnostic of dehydrins, but no serine tract (S-segment) and no Y-segment. Temporally, accumulation of the dehydrin transcript coincides with accumulation of the protein, which remains high in the bud scales of the inflorescence throughout winter. The dehydrin protein accumulates in the outer leaves (scales) of the inflorescence bud and in the bark of 1-year-old stems. In the buds it is mostly concentrated in the palisade-like cells underneath the epidermis, in the bud and in the inner bark parenchyma. Immunogold labeling revealed that it is a cytoplasmic protein with no specific organellar localization. It is suggested that the dehydrin of pistachio may have a dual function, a role in drought and cold tolerances, as well as serving as a storage protein.

The poplar bark storage protein gene (Bspa) promoter is responsive to photoperiod and nitrogen in transgenic poplar and active in floral tissues, immature seeds and germinating seeds of transgenic tobacco.

In Populus, seasonal nitrogen storage involves the accumulation of a 32 kDa bark storage protein (BSP) in the inner bark parenchyma and xylem rays. Poplar BSPs are encoded by a multigene family and one member, bspA, has been cloned and sequenced. The regulation of bspA was investigated by transforming either hybrid poplar or tobacco with a chimeric gene consisting of the 2.8 kb bspA promoter fused to the coding region of beta-glucuronidase (uidA). In transformed poplar, the bspA 2.8 kb promoter conferred both short-day (SD) and nitrogen (N) inducibility to GUS and activity was localized to the bark (primary and secondary phloem, and cortex) and xylem rays. Night-break treatments inhibited SD induction of GUS. Deletion of the 1.6 kb distal DNA sequences from the bspA promoter eliminated SD induction of GUS while some N induction was retained. These results indicate that although poplar BSP is encoded by a multigene family, transcriptional activation of bspA per se can account for bsp expression in bark and xylem rays in response to either SD or N treatment. These results also show that the elements responsible for SD or N induction are separable. Because of the long generation intervals associated with trees, the developmental regulation of bspA in flowers, developing seeds, and germinating seeds was investigated by transforming the 2.8 kb bspA-promoter::uidA chimeric gene into tobacco. The bspA promoter was active in developing tobacco floral tissues and in seeds during early stages of embryogenesis, decreased progressively during seed maturation and regained activity upon seed germination. Although seed storage proteins of poplar share some similarities to poplar BSP, the observed developmental expression patterns in tobacco are consistent with a role for bspA in vegetative rather than seed storage protein storage.

Early Scion/Stock Junction in Compatible and Incompatible Pear/Pear and Pear/Quince Grafts: a Histo-cytological Study

A comparative histo-cytological study of compatible and incompatible pear/pear and pear/quince grafts, grown in a glasshouse, was carried out on unions collected from day 1 to day 22 after budding (DAB). Successive steps leading to the graft junction were studied. Adhesion between the two partners was observed along the inner bark tissues (phloem and cambium) just 24 h after budding, while a necrotic layer appeared at the graft interface. The first cell divisions were observed 3 DAB. In the inner bark interface these led to the formation of a junction callus, inside which new cambial strands (neocambia) appeared between 10 and 15 DAB, starting from the cut edges of the scion and stock cambia, and joining later when they began to produce both phloem and xylem derivatives. Along the outer bark interface, where the cut surfaces of the bark parenchyma were exposed to the air, divisions of the parenchyma cells gave rise to a new phellogen layer (neophellogen) approx. 6 DAB, and suber production was observed 10 DAB. No obvious differences were noticed between compatible and incompatible grafts during the first stages of graft junction. No particular cell necrosis phenomenon was observed at the interface of incompatible grafts. Nevertheless, the neocambial junction appeared to be delayed in pear/quince heterografts, especially in incompatible ones. This could be the first structural event of the incompatibility response in pear/quince grafts.

Early Scion/Stock Junction in Compatible and Incompatible Pear/Pear and Pear/Quince Grafts: a Histo-cytological Study

A comparative histo-cytological study of compatible and incompatible pear/pear and pear/quince grafts, grown in a glasshouse, was carried out on unions collected from day 1 to day 22 after budding (DAB). Successive steps leading to the graft junction were studied. Adhesion between the two partners was observed along the inner bark tissues (phloem and cambium) just 24 h after budding, while a necrotic layer appeared at the graft interface. The first cell divisions were observed 3 DAB. In the inner bark interface these led to the formation of a junction callus, inside which new cambial strands (neocambia) appeared between 10 and 15 DAB, starting from the cut edges of the scion and stock cambia, and joining later when they began to produce both phloem and xylem derivatives. Along the outer bark interface, where the cut surfaces of the bark parenchyma were exposed to the air, divisions of the parenchyma cells gave rise to a new phellogen layer (neophellogen) approx. 6 DAB, and suber production was observed 10 DAB. No obvious differences were noticed between compatible and incompatible grafts during the first stages of graft junction. No particular cell necrosis phenomenon was observed at the interface of incompatible grafts. Nevertheless, the neocambial junction appeared to be delayed in pear/quince heterografts, especially in incompatible ones. This could be the first structural event of the incompatibility response in pear/quince grafts.

Photoperiod Control of Poplar Bark Storage Protein Accumulation

Bark storage proteins (BSPs) accumulate in the inner bark parenchyma of many woody plants during autumn and winter. We investigated the effect of a short-day (SD) photoperiod on the accumulation of the 32-kilodalton bark storage protein of poplar (Populus deltoides Bart. ex Marsh.) under controlled environmental and natural growing conditions. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and protein gel blot analysis revealed that 10 days of SD exposure (8 hours of light) resulted in a 20% increase in the relative abundance of the 32-kilodalton bark storage protein of poplar. After 17 days of SD exposure, the 32-kilodalton bark storage protein accounted for nearly one-half of the soluble bark proteins. In natural field conditions, accumulation of the 32-kilodalton bark storage protein was observed to start by August 18 (daylength 14.1 hours). Immunoprecipitation of in vitro translation products with anti-BSP serum revealed that the SD protein accumulation was correlated with changes in the pool of translatable mRNA. A survey of poplar clones from different geographic origins revealed the presence of the 32-kilodalton BSP in the dormant bark of all the clones tested. These results demonstrate that a SD photoperiod induces, whether directly or indirectly, rapid changes in woody plant gene expression, leading to the accumulation of BSP.

Biomass chemicals: Improvement in quality and quantity with physiological regulators

The search for alternative biomass energy forms has centered on two approaches: (1) production of cellulose fiber in biomass of low net energy value per unit weight, such as wood and bagasse, and (2) hydrocarbons of high net energy value per unit weight for use as chemical feedstocks and substitutes for petroleum. Major plant chemical products include oleoresin from pine ( Pinus elliottii Engelm., P. palustris Mill.), rubber from the rubber tree ( Hevea brasiliensis Muell.), and guayule shrub ( Parthenium argentatum Gray) and sugar from sugarcane ( Saccharum spp.). Genetic selections with lower natural yields tend to respond the most to bioregulators, and yields after treatment may equal those of the best selections also receiving the treatment. Ethylene may be a unifying natural bioregulator that can increase deposition of biomass chemicals in all four of these systems. The underlying success of the bioregulators is that assimilates are partitioned into extractives and sugar instead of vegetative growth. Examples include the use of paraquat, diquat, and 2-chloroethylphosphonic acid (CEPA) for stimulating the synthesis of oleoresin, CEPA for prolonging the flow of rubber and increasing rubber synthesis in the rubber tree, and triethylamines of chlorinated phenoxy compounds for stimulating rubber production in guayule. In sugarcane, gibberellic acid (GA 3) increases internodal elongation. Glyphosate, CEPA and other regulators increase the deposition of sucrose, diquat and CEPA inhibit flowering, and paraquat desiccates leaves just prior to harvest to facilitate leaf removal or burning just prior to harvest. The cellular compartmentalization for the synthesis of these plant chemicals is unique for each species, and dictates cultural and harvest techniques. Oleoresin is produced in the epithelial cells of resin canals and parenchyma of rays. Hevea rubber is produced in articulated laticifers. Hevea rubber and pine oleoresin are obtained by stripping away bark at various intervals during the year. The main source of guayule rubber is bark parenchyma and it is obtained by grinding the shrub, and coagulating and extracting the rubber. Sucrose is synthesized in the cytosol, stored in plastids and obtained by harvesting the cane and crushing it. The mode of action and pathways for the success of these physiological regulators are discussed.

Host relations and distribution of a physiological and pathological variant of Pseudomonas morsprunorum

SUMMARYIn a plot of sweet‐cherry trees (Primus avium), leaf spot infections caused by Pseudomonas morsprunorum were more abundant on the cv. Roundel than on the normally more susceptible cv. Napoleon. Roundel also supported significantly higher leaf surface populations of the pathogen. This reversal in the relative field susceptibility of the two cultivars was associated with the presence on the trees of a variant form of P. morsprunorum that differed from typical strains in colony structure, gelatinase activity and pathological characters. The variant strains were less infective through leaf scars but more invasive in bark parenchyma than typical strains, and in branch and leaf inoculations, they showed specialization for the cv. Roundel. This specialization was reflected in the distribution of variant and typical strains on Roundel and Napoleon trees in other localities. The significance of the variant in relation to disease epidemiology and cultivar resistance is discussed. The variant is designated race 2 to distinguish it from the typical, or race 1 cherry strains of P. morsprunorum.

A staining procedure for latex vessels of Hevea.

It is difficult to stain Hevea latex vessels and other bark parenchyma cells differentially. A method to identify the latex vessels by staining the coagulated latex in them is described here. Hevea bark, on removal, was immediately fixed in formal-acetic-alcohol for 24–36 h, then dehydrated in tertiary butyl alcohol and embedded in paraffin wax, mp 58d`C. A few drops of oleic acid were added to the wax to retain the coagulated latex. The wax ribbons were mounted on slides and dewaxed in Coplin jars containing a 55:45 mixture of toluene and absolute ethyl alcohol at 60d`C for 11/2 h. The sections were then rinsed in 95% ethyl alcohol and stained with the following solutions, all made up in absolute ethyl alcohol: (a) Old bark: 2 ml 2% oil red 4B, 3 ml 1% methyl green, 3 ml 2% light green, and 2 ml saturated aniline sulfate; (b) Young bark: 6 ml 2% oil red 4B, 4 ml 2% light green, 2 ml 10% safranin, 1 ml 2% aniline sulfate.