Tissue Structure Changes of Aquilaria sinensis Xylem after Fungus Induction

In this study, we analyzed the mechanism and the process of fungal-induced agarwood formation in Aquilaria sinensis and studied the functional changes in the xylem structure after the process. The microscopic structure of the white zone, transition zone, agarwood zone, and decay zone of 12-and 18-months of inoculation A. sinensis xylem was studied. The distribution of nuclei, starch grains, soluble sugars, sesquiterpenes, fungal propagules, and mycelium in xylem tissues was investigated by histochemical analysis. The results show that the process of agarwood formation was accompanied by apoptosis of parenchyma cells such as interxylary phloem, xylem rays, and axial parenchyma. Regular changes in the conversion of starch grains to soluble sugars, the production of sesquiterpenoids, and other characteristic components of agarwood in various types of parenchyma cells were also observed. The material transformation was concentrated in the interxylary phloem, providing a structural and material basis for the formation of agarwood. It is the core part of the production of sesquiterpenoids and other characteristic products of agarwood. Compared with the A. sinensis inoculated for 12 months, the xylem of the A. sinensis inoculated for 18 months was more vigorous. There were no significant differences between the 12 and 18 months of inoculation in terms of sugars and agarwood characteristic products. In production, harvesting after 12 months of inoculation can improve harvesting efficiency.

Characterizing Hyperspectral Microscope Imagery for Classification of Blueberry Firmness with Deep Learning Methods

Firmness is an important quality indicator of blueberries. Firmness loss (or softening) of postharvest blueberries has posed a challenge in its shelf-life quality control and can be delineated with its microstructural changes. To investigate spatial and spectral characteristics of microstructures based on firmness, hyperspectral microscope imaging (HMI) was employed for this study. The mesocarp area with 20× magnification of blueberries was selectively imaged with a Fabry–Perot interferometer HMI system of 400–1000 nm wavelengths, resulting in 281 hypercubes of parenchyma cells in a resolution of 968 × 608 × 300 pixels. After properly processing each hypercube of parenchyma cells in a blueberry, the cell image with different firmness was examined based on parenchyma cell shape, cell wall segment, cell-to-cell adhesion, and size of intercellular spaces. Spectral cell characteristics of firmness were also sought based on the spectral profile of cell walls with different image preprocessing methods. The study found that softer blueberries (1.96–3.92 N) had more irregular cell shapes, lost cell-to-cell adhesion, loosened and round cell wall segments, large intercellular spaces, and cell wall colors that were more red than the firm blueberries (6.86–8.83 N). Even though berry-to-berry (or image-to-image) variations of the characteristics turned out large, the deep learning model with spatial and spectral features of blueberry cells demonstrated the potential for blueberry firmness classification with Matthew’s correlation coefficient of 73.4% and accuracy of 85% for test set.

The Spatial Orientation and Interaction of Cell Wall Polymers in Bamboo Revealed with a Combination of Imaging Polarized FTIR and Directional Chemical Removal

The mechanical and physical properties of lignocellulosic materials are closely related to the orientation and interaction of the polymers within cell walls. In this work, Imaging Polarized FTIR, combined with directional chemical removal, was applied to characterize the spatial orientation and interaction of cell wall polymers in bamboo fibers and parenchyma cells from two bamboo species. The results demonstrate the cellulose in bamboo fibers is nearly axially oriented whereas it is almost transversely arranged in parenchyma cells. Xylan and lignin are both preferentially oriented alongside cellulose, but with less orientation degre in the parenchyma cells. After lignin removal, the average orientation of xylan and cellulose is little affected, suggesting a strong interaction between cellulose and xylan. Meanwhile, the alkaline treatment significantly weakens the orientation of lignin in both fibers and parenchyma cells, and more significant for the latter, indicating the easy-degradable nature of lignin in parenchyma cells. And, it seemed the lignin and xylan in fibers were more difficult to be removed as compared to parenchyma cells, supporting the assumption that stronger interaction exists between lignin and xylan in the fibers. In a word, it was believed parenchyma cells are more suitable for biorefinery owing to its less ordered and relatively loose molecular assembly, as compared to fibers.

Leaf ontogenesis of Trembleya phlogiformis DC. (Microlicieae, Melastomataceae): functional aspects and indumentum characterization

Leaf ontogenesis is determinant for the establishment and regulation of its structural and functional properties, in addition to being an excellent tool for assignment to different groups of angiosperms. Even though the importance of leaf morphology and anatomy for taxonomic use is well known, few studies have addressed the processes of leaf ontogeny in Melastomataceae. Herein, we sought to define the ontogenetic steps of leaf of Trembleya phlogiformis, highlighting the indumentum, to understand the main functional traits. Shoot apex, young and fully expanded leaves were processed by usual light microscopy procedures. At the first node, leaf primordia are densely covered with trichomes and emergences. The adaxial layer of ground meristem gives rise to the palisade parenchyma, the procambium originates from median layers of ground meristem and the spongy parenchyma develops from abaxial layers of ground meristem. The differentiation of isobilateral mesophyll on leaves of T. phlogiformis, a common feature in Microlicieae, comes from ground meristem stratification. However, T. phlogiformis stands out by showing in the leaf mature spongy parenchyma cells with irregular shapes. The leaf ontogeny reveals distinct mechanisms of cell differentiation and may be important for the establishment of functional adaptive traits.

Comparative Wood Anatomy in Pinaceae with Reference to Its Systematic Position

The wood anatomy of 132 species of the genera Abies, Cathaya, Cedrus, Keteleeria, Larix, Nothotsuga, Picea, Pinus, Pseudolarix, Pseudotsuga and Tsuga was studied to determine the elements that characterise the xylem of each genus and discuss possible groupings by wood anatomy for comparison with clades established by molecular phylogeny. The presence of resin canals and ray tracheids supports the family Pinaceae, although the absence of ray tracheids in Keteleeria and their occasional presence in Abies and Pseudolarix weakens it. Based on wood structure, Pinaceae clearly supports division into two groups, coinciding with molecular phylogeny: Pinoideae (Cathaya-Larix-Picea-Pinus-Pseudotsuga) and Abietoideae (Abies-Cedrus-Keteleeria-Nothotsuga-Pseudolarix-Tsuga). Although differences between genera are slight in Pinoideae, the Abietoideae group presents problems such as the presence of only axial resin canals in Keteleeria and Nothotsuga, absence of ray tracheids in Keteleeria and presence of traumatic radial resin canals in Cedrus. However, other features such as pitted horizontal walls and nodular end walls of ray parenchyma cells, indentures, scarce marginal axial parenchyma and presence of crystals in ray parenchyma strengthen the Abietoideae group.

Cell Wall Pore Structures of Bamboo as Relation to Species and Tissue Types

Efficient convention of bamboo biomass into biofuel and biomaterials, as well as chemical treatment are both highly related to the porosity of cell wall. The present work characterizes the micropore and mesopore structure in cell walls of six different bamboo species and tissue types using CO2 and N2 adsorption. Two plantation wood species were also tested for comparison. Bamboo species normally showed lower cell wall porosity (2.64%-3.75%) than wood species (3.98%-5.06%), indicating a more compact structure for bamboo than wood. A distinct species dependence of cell wall pore structures and porosity was also observed. Furthermore, the cell wall pore structure and porosity are shown to be tissue-specific, as the parenchyma cells exhibit higher pore volume and porosity compared to bamboo fibers. The obtained results give new explanations on the known facts that both bamboo and bamboo fibers exhibit higher biomass recalcitrance as compared to wood and bamboo parenchyma cells, constructing the base of pretreatment optimization and subsequent processing for bamboo-derived biofuels and biomaterials.

Anatomy and cell wall ultrastructure of sunflower stalk rind

The anatomy and ultrastructure of sunflower stalk rind are closely related to its conversion and utilization. We studied systematically the anatomy and ultrastructure of the stalk rind using light, scanning electron, transmission electron and fluorescence microscopy. The results showed that the stalk rind consisted of phloem fibers (PF), xylem fibers (XF), vessel elements (V), ground parenchyma cells (GPC), axial parenchyma cells (APC), xylem ray parenchyma cells (XRPC), and pith ray parenchyma cells (PRPC). These cell walls were divided into the middle lamella, primary wall, and secondary wall (S). It was found that the S of PF, XF and V was further divided into three layers (S1–S3), while the S of APC, GPC, XRPC and PRPC showed a non-layered cell wall organization or differentiated two (S1, S2) to seven layers (S1–S7). Our research revealed the plasmodesmata characteristics in the pit membranes (PMs) between parenchyma cells (inter-GPCs, inter-XRPCs, and inter-PRPCs). The morphology of the plasmodesmata varied with the types of parenchyma cells. The thickness and diameter of PMs between the cells (inter-Vs, V–XF, V–APC, and V–XRPC) were greater than that of PMs between parenchyma cells. The cell corners among parenchyma cells were intercellular space. The lignification degree of vessels was higher than that of parenchyma cells and fibers. The results will provide useful insights into the biological structure, conversion and utilization of sunflower stalk rind.

Paleobotany collections: fossil woods available at the Bandung Geological Museum

Indonesia is a country which has plants species diversity. The form of ancient plants that grew in the past are recorded as fossil woods. Several fossil woods from regions in Indonesia were collected and became exhibition collections at the Bandung Geological Museum. These fossil woods on display requires biology identity to provide more information to visitors. Identification of species of fossil woods were carried out based on the anatomical features on the smoothed cross-section. Observations were carried out by a loop hand (a magnification of 10 times and a digital loop (with a magnification of 16 times). The fossil woods anatomy features observed included vessel cells, parenchyma cells, rays cells, and the presence of resin channels. The fossil specimen which had unclear anatomy features compared by detailed description of wood anatomy available at the library and collections of wood samples owned by the Xylarium Bogoriense. The fossil woods species are Canarioxylon sp., Terminalioxylon sp., Anisopteroxylon sp., Dipterocarpoxylon sp., Dryobalanoxylon sp., Hopenium/Hopeoxylon sp., Shoreoxylon sp., Kompassioxylon sp., and Xanthophyllum sp. The mostly fossil woods species resvectively belonging to the Dipterocarpaceae, Combretaceae, Polygalaceae, Burseraceae, and Leguminosae. The fossil woods member of Dipterocarpaceae family are conspicuously characterized with the presence of resin canals.

Characterization of ground parenchyma cells in Moso bamboo (Phyllostachys edulis–Poaceae)

Ground parenchyma cells play a crucial role in the growth and the mechanical properties of bamboo plants. Investigation of the morphology of ground parenchyma cells is essential for understanding the physiological functions andmechanical properties of these cells. This study aimed to characterize the anatomical structure of bamboo ground parenchyma cells and provide a qualitative and quantitative basis for the more effective utilization of bamboo. To do this, the morphology of ground parenchyma cells in Moso bamboo (Phyllostachys edulis) was studied using light microscopy and field-emission environmental scanning electron microscopy. Results show that various geometric shapes of ground parenchyma cells were observed, including nearly circular, square, long, oval, and irregular shapes. Cell walls of both long and short parenchyma cells exhibited primary wall thickening and secondary wall thickening, resulting in a primary pit field and simple pits. Most long cells were strip-shaped (L/W = 2.52), while most short cells were short and wide (L/W = 0.59). The proportion of long cells was 11 times greater than that of short cells. Most long cells were filled with starch grains, and some short cells also occasionally had starch grains. These findings allowed the first construction of the three-dimensional structure of parenchyma cells.