Listening to ultrasound from plants reveals xylem vessel anatomy. Ultrasound characterization of plant vessels.

Although it is well known that plants emit ultrasound bursts under drought stress, the exact origin of the acoustic waveform of these pulses has remained elusive. Here we present evidence for a correlation between the ultrasound spectrum of these pulses and the dimensions of the plant’s xylem vessels. Using a model that relates the vibrational excitations of the vessels to their geometric and viscoelastic properties, we develop a methodology to extract the internal xylem vessel dimensions from recorded ultrasound waveforms. We apply the method to ultrasound pulses from drying shoots of three vascular dicot plant species, and validate it by comparison with destructive measurements via microscopy. Our method demonstrates the potential for continuous monitoring of the vascular anatomy of plants. The ultrasonic, non-invasive characterization of internal vessel dimensions can lead to breakthroughs in speed and accuracy in plant phenotyping and disease detection in agriculture.

Listening to ultrasound from plants reveals xylem vessel anatomy

Plants emit ultrasound pulses under drought stress, which originate in their water-carrying xylem vessels, and can be recorded externally. We demonstrate that these ultrasound pulses consist of superposed damped oscillations at plant-specific frequencies in the range of 10 – 150 kHz, that are correlated to xylem dimensions. We present a method to relate geometrical and viscoelastic properties of xylem vessels with the time- and frequency-domain characteristics of the observed oscillations. We apply the method to ultrasound pulses from drying shoots of three vascular dicot plant species. The extracted parameters are validated with destructive measurements of xylem vessel radii, wall thickness, length of xylem vessel elements, and the elastic modulus of the vascular bundle by optical and scanning cryo-electron microscopy and tensile loading. Our method demonstrates the potential for non-invasive and continuous monitoring of plant vascular anatomy. We foresee applications in high-throughput phenotyping and early detection of vascular wilt diseases.

Pharmacognostic Investigation of Leaves and Bark of Cochlospermum Religiosum Linn

Cochlospermum religiosum (Linn.) Alston. (Bixaceae) otherwise known as Yellow silk cotton tree.Traditionally, the plant is used in the treatment of cough, asthma, jaundice, tuberculosis, inflammation, gonorrhea, fever and dysentery. In the present studymicromorphological investigations and the physicochemical analysis of Cochlospermum religiosumleaves and stem bark were carried out.The macromorphological examination indicated simple, palmately lobed, alternate distichous leaves possessing the prominent parallel venation, acute apices and crenate margin. Similarly, smooth, fibrous, ash coloured bark containing an orange-coloured gummy exudate observed. The microscopy of leaves presented a dorsiventral lamina, long filamentous unicellular uniseriate covering trichomes, anomocytic stomata, annulated lignified xylem vessel, mucilaginous brown matter, starch grains and prisms of calcium oxalate whereas the microscopic examination of the bark indicated lignified cork cells, thick-walled lignified sclereids, bundles of lignified fibres, rounded starch grains, elongated cellulosic medullary rays, tetragonal and rosette crystals of calcium oxalate. Thequalitative analysis of inorganic elementsexhibited the presence of aluminium, sodium, calcium, chlorides and ironin leaves and the bark ofCochlospermum religiosum.The present investigation on pharmacognostic characters and analytical standards of Cochlospermum religiosumwill provide a diagnostic tool in the authentication and the assessment of its quality.

Structure and Biomechanics during Xylem Vessel Transdifferentiation in Arabidopsis thaliana

Individual plant cells are the building blocks for all plantae and artificially constructed plant biomaterials, like biocomposites. Secondary cell walls (SCWs) are a key component for mediating mechanical strength and stiffness in both living vascular plants and biocomposite materials. In this paper, we study the structure and biomechanics of cultured plant cells during the cellular developmental stages associated with SCW formation. We use a model culture system that induces transdifferentiation of Arabidopsis thaliana cells to xylem vessel elements, upon treatment with dexamethasone (DEX). We group the transdifferentiation process into three distinct stages, based on morphological observations of the cell walls. The first stage includes cells with only a primary cell wall (PCW), the second covers cells that have formed a SCW, and the third stage includes cells with a ruptured tonoplast and partially or fully degraded PCW. We adopt a multi-scale approach to study the mechanical properties of cells in these three stages. We perform large-scale indentations with a micro-compression system in three different osmotic conditions. Atomic force microscopy (AFM) nanoscale indentations in water allow us to isolate the cell wall response. We propose a spring-based model to deconvolve the competing stiffness contributions from turgor pressure, PCW, SCW and cytoplasm in the stiffness of differentiating cells. Prior to triggering differentiation, cells in hypotonic pressure conditions are significantly stiffer than cells in isotonic or hypertonic conditions, highlighting the dominant role of turgor pressure. Plasmolyzed cells with a SCW reach similar levels of stiffness as cells with maximum turgor pressure. The stiffness of the PCW in all of these conditions is lower than the stiffness of the fully-formed SCW. Our results provide the first experimental characterization of the mechanics of SCW formation at single cell level.

Differences in leaf area, trichome density, and xylem structure between the two types of Theobroma cacao l. cultivation: With or without shade plants

This study aimed to analyze the structure and density of non-glandular trichomes and the area of cocoa leaves, and the differences of xylem vessel structures on various shade tree composition. The leaf area and length, and trichomes were observed. The xylem vessel structure was observed from the root system. The result showed the area of cocoa plots without shade tree has more varied leaves size, in which upper canopy was smaller than the bottom. The area with various shade had a relatively equal size between the upper and the lower of the canopy. The three stellate-shaped non-glandular trichomes were found on the leaf venations only with the density in two plots increased with time. The xylem width area to the whole root width area ratio (k) in various shade trees was lower (k= 0.641) than that of without shade trees (k= 0.718). The higher k values indicated xylem structure without the shade tree had more xylem cells, and the pores was smaller compared to the plot with various shade trees.