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Abstract

The covid-19 pandemic has wreaked havoc on the global healthcare system and the economy. At present, no specific antiviral vaccine is available to combat this contagious virus. Traditional medicine has a long history of playing a significant role in managing several infectious diseases. In this context, scientists around the globe are also exploring various traditional medical interventions to prevent the covid-19 pandemic. In the present work, we summarize available scientific data advocating the use of traditional medicine for preventing covid-19. A robust literature review was conducted using scientific platforms such as Science Direct, National Center for Biotechnology Information (ncbi), Pubmed, Google Scholar, and online database like The Plant List (The Plant List 2013) version 1.1. Special emphasis was given to potential natural antiviral, immuno-modulator plants, and traditional medicines to highlight their possible roles in reducing the disease burden. Immuno-modulator such as Withania somnifera and other natural compounds especially glycyrrhizin, kaempferol, ginsenoside, and lycorine can be leading candidates against sars-CoV-2. Besides the need for rigorous scientific validation of potential herbs and related formulations, their use can be beneficial for the preventive as well as symptomatic treatment of covid-19 infected patients. This work provides a run-through of the experimental therapeutics, preventive and treatment options for covid-19.

In: Israel Journal of Plant Sciences
Maria Sibylla Merian’s Caterpillar Book
Author: Kay Etheridge
The Flowering of Ecology presents an English translation of Maria Sibylla Merian’s 1679 ‘caterpillar’ book, Der Raupen wunderbare Verwandelung und sonderbare Blumen–Nahrung. Her processes in making the book and an analysis of its scientific content are presented in a historical context. Merian raised insects for five decades, recording the food plants, behavior and ecology of roughly 300 species. Her most influential invention was an 'ecological' composition in which the metamorphic cycles of insects (usually moths and butterflies) were arrayed around plants that served as food for the caterpillars. Kay Etheridge analyzes the 1679 caterpillar book from the viewpoint of a biologist, arguing that Merian’s study of insect interactions with plants, the first of its kind, was a formative contribution to natural history.

Abstract

Members of the Convolvulaceae are characterized by the climbing habit and occurrence of variant secondary growth. From a histological perspective, the genus Ipomoea L. is the most extensively studied, while other genera have been less studied. Here, stem anatomy of the least studied genus in the family, Hewittia Wight & Arn., represented by Hewittia malabarica (L.) Suresh was investigated using classical histological techniques. In both the samples collected from India and South Africa, stem thickness increased by developing different types of cambial variants such as: neo-formed vascular cylinders, parenchyma proliferation at the phloem wedges, ray-derived cambia from dilating phloem rays, internal cambium, intra- and interxylary phloem. Neo-formed vascular cylinders develop from the parenchyma cells external to the phloem as a meristemoid in thick stems and later in dilating ray cells. With the increase in stem diameter, cells of the phloem wedges showed proliferation by meristematic activity, which form a connection with the cortex by rupturing the primary tissue ring of eustele. Subsequently, development of cambium in phloem wedges and deposition of its derivatives increased the tangential width of rays. Mature thick stems (25–30 mm) give rise to a fissured stem. Intraxylary (internal) phloem development on the pith margin was observed from primary growth onwards and in thick stems secondary intraxylary phloem developed from the internal cambium. Internal cambium is functionally bidirectional and produces secondary xylem internally and secondary phloem externally. In all the samples, patches of unlignified parenchyma embedded within the secondary xylem dedifferentiate and mature into interxylary phloem with the increasing age. Development of cambial variant and structure of the secondary xylem is correlated with the functional significance of the climbing habit.

In: IAWA Journal

Abstract

This study provides a detailed analysis of phloem anatomy, development, the formation of cell types, differentiation, and sieve-tube element’s longevity in two tropical arboreal species, Cedrela fissilis (Meliaceae, Rosid) and Citharexylum myrianthum (Verbenaceae, Asterid), growing in natural populations in the semi-deciduous Atlantic Rainforest. We periodically collected samples from the main stem at breast height (1.3 m), during both the dry and the wet seasons. Differences in the cells produced at these different seasons suggest that annual growth increments in the phloem are present in both species, marked by files of terminal narrow sieve-tube elements radially grouped in Cedrela fissilis, and in assemblages of narrow sieve tubes and axial parenchyma in Cytharexylum myrianthum, both appearing at the end of the wet season. In Cedrela fissilis, where fiber bands are present, each fiber band marks the end of the early phloem, acting as an indirect annual growth ring marker. Sieve-tube element longevity varied for both species from 4–26 months, a result similar to that obtained in temperate species.

In: IAWA Journal

Abstract

In many regions, such as the Mediterranean, anticipated climate change is seen as a serious threat to tree vitality and forest productivity. Recent studies show that wood and bark structure as well as the number of dormant cambial cells bear valuable information about the growth condition and vitality of trees and thus could function as indicators to help manage forests in the future. Microcores and tree cores were sampled from stems of adult Cedrus libani trees growing at different altitudes in SW-Turkey. Trees were divided into two groups based on basal area increments: vital trees (positive growth trend), and trees of diminishing vitality (negative growth trend). Histological cross-sections were investigated for their number of dormant cambial cells as well as their xylem and phloem characteristics. We measured the widths of the conducting phloem, most recent xylem ring, earlywood, and latewood. We further calculated the ratio between the width of xylem ring and conducting phloem (XR:CPH ratio), and earlywood to latewood ratio. Vital trees had a significantly higher number of dormant cambial cells (on average 32%), higher xylem (67%), and conducting phloem (36%) widths, and a higher XR:CPH ratio (47%). The XR:CPH ratio ranged between 1.8:1 and 21.4:1. The number of dormant cambial cells was closely related to xylem and conducting phloem widths and showed a significant decrease with tree age. Altitude showed no direct effect on the measured and calculated parameters. Our results indicate the potential of dormant cambium, xylem, and phloem characteristics to assess the vitality and growth conditions of C. libani trees.

In: IAWA Journal
In: The Flowering of Ecology
In: The Flowering of Ecology
In: The Flowering of Ecology
In: The Flowering of Ecology
In: The Flowering of Ecology