Comparative Analyses of the Self-Sealing Mechanisms in Leaves of Delosperma cooperi and Delosperma ecklonis (Aizoaceae)

Within the Aizoaceae, the genus Delosperma exhibits a vast diversification colonizing various ecological niches in South-Africa and showing evolutionary adaptations to dry habitats that might include rapid self-sealing. Leaves of Delosperma react to external damage by the bending or contraction of the entire leaf until wound edges are brought into contact. A study of leaf morphology and anatomy, biomechanics of entire leaves and individual tissues and self-sealing kinematics after a ring incision under low and high relative humidity (RH) was carried out comparing the closely related species Delosperma cooperi and Delosperma ecklonis, which are indigenous to semi-arid highlands and regions with an oceanic climate, respectively. For both species, the absolute contractions of the examined leaf segments (“apex”, “incision”, “base”) were more pronounced at low RH levels. Independent of the given RH level, the absolute contractions within the incision region of D. cooperi were significantly higher than in all other segments of this species and of D. ecklonis. The more pronounced contraction of D. cooperi leaves was linked mainly to the elastic properties of the central vascular strand, which is approximately twice as flexible as that of D. ecklonis leaves.

ANATOMICAL STUDIES OF THE FRUIT OF ZIZIPHUS RUGOSA

Objective: The objective of this study was to study the anatomical features of the fruit Ziziphus rugosa. Methods: Surface view, longitudinal, transverse section (T.S), and powder microscopy of the fruits were studied. Results: The fruit is a drupe and shows vertical, irregular brown markings on the surface. The surface of the seed has irregular reticulate thick marking of brown. The longitudinal sections (L.S) of the fruit show thin green epicarp, wide soft mesocarp, and dark brown thick endocarp. In longitudinal view, the seed shows a thick conical part, thick wide shell which is hard. In the cotyledon is more or less cordate,white and soft with shallow notch at the upper end. In T.S, the fruit appears circular with soft pericarp, thick dark brown seed coat of sclereids, and vertically elongated white cotyledon. The epicarp layer is broken at certain places. In the mesocarp, some of the cells have dense tannin content and others have mucilage substance. The mucilaginous canals are wide, unbranched, and wavy. Some of the mesocarp cells contain dense accumulation of protein bodies. The sclerotesta contains palisade or macrosclereids. The seed consists of two elliptical, flat cotyledons which show dense accumulation of starch grains and small less prominent vascular strand. The powder microscopy of the fruit contains abundant dark mucilaginous substance. Fragments of epidermal cells of the pericarp and mesocarp cells are frequently seen. The seed coat epidermal cells are polyhedral with lignified cell walls. The circular brachy sclereids were often seen in the mesophyll tissue of the fruit. The ground parenchyma with various shapes and size is also noticed. Conclusion: This study revealed the presence of mucilaginous substance, tannin, sclereids, starch grains, and protein bodies. Therefore, this material will be efficient for eliminating some nutritional deficiency diseases.

Pharmacognostic and Physico-Chemical Investigation of Hemionitis Arifolia (Burm.)Moore.

Hemionitis arifolia (Family-Adiantaceae)is an attractive and unusual dwarf fern.It is used folkloric to treat ear ache, migraine, haemorrhoids, arthritis, intestinal worms and wounds.It has been medically evaluated for its hypoglycaemic and anti-diabeticproperties in rats.The present investigation deals with macroscopic and microscopic evaluation of the leaf material and establishment of its quality parameters, including physicochemical and phytochemical evaluation.Macroscopy revealed lamina as dimorphous, simple; sterile fronds deeply cordate, margin entire, apex rounded; lower surface light green with scattered, appressed scales and hairs, densely along the midrib sparsely on surface. In the microscopic studies, the lamina is isobilateral and has no distinction of adaxial and abaxial sides.The vascular strand consists of a wide, bow shaped row of xylem elements; the two margins of the xylem strand are thin; the middle part being thick. Phloem occurs in thin band both on the lower and upper portions of the xylem arc. Chief characters of powder include epidermal cells, elliptical stomata, multicellular, uniseriate trichomes, xylem elements. Physicochemical parameters such as moisture content, chlorophyll estimation, fluorescence analysis, ash values and extractive values were done. Phytochemical screening revealed the presence of many therapeutically important classes of phytoconstituents such as glycosides, phenolics, flavonoids, carbohydrate, terpenoids, sterols and saponins. Thus this study can serve as a valuable source of information and provide suitable standards for identification of this plant material in future investigations and applications.

Psilophyton szaferi sp. nor. from the Lower Devonian of the Holy Cross Mountains. Poland

<em>Philophyton szaferi</em> sp. nov. belonging to the <em>Trimerophytina</em> was found in the Lower Devonian (Emsian) in the bore-hole Modrzewie 2A near Bostów in the Holy Cross Mountains (Gory Świętokrzyskie). The axes are sterile and fertile. their branching is dichotomous, unequally dichotomous and unequally dochotomous where the wider branch tends to form the main axis. The majority of axes branch in one plane, some in different planes; they show on their surface irregularly distributed enations in the form of rounded swellings. Some of them continue downwards as protruding ridges forming a characteristic longitudinal pattern. The apices of sterile axes are forking. Fertile axes end in clusters of fusiform. upright sporangia, arranged in pairs. The vascular strand shows protoxylem inside and metaxylem outside. Tracheids possess scalariform thickenings and what appear to be small pits between them. The systematic position of the plant and its position in the evolutionary sequence leading to megaphyllous leaves is discussed.

Genetic evidence for differences in the pathways of druse and prismatic calcium oxalate crystal formation in Medicago truncatula

Current evidence supports a single pathway of oxalate biosynthesis utilising ascorbic acid as the precursor. In this study, we begin to address the possibility that more than one pathway of oxalate biosynthesis and calcium oxalate formation occurs in Medicago truncatula Gaertn. (cv. Jemalong genotype A17). Like the wild type, developing leaves of the calcium oxalate defective (cod) 4 mutant contain prismatic crystals along the vascular strand, but this mutant also hyper-accumulates druse crystals within the mesophyll cells. A second mutant, cod5, fails to accumulate prismatic crystals along the vascular strand, but is capable of wild type druse crystal accumulation in maturing leaves. To assess whether a single pathway of oxalate biosynthesis and calcium oxalate formation occurs in M. truncatula, we generated and characterised the cod4/cod5 double mutant. Microscopic examination of the cod4/cod5 revealed that the double mutant exhibits both cod4 and cod5 mutant crystal phenotypes simultaneously, suggesting there are differences in the pathways leading to the two crystal types. Measured ascorbic acid levels and ascorbate induction studies were consistent with the acid as precursor to oxalate in druse crystal formation but not necessarily prismatic crystal formation. On the basis of these findings, we propose a working model depicting possible pathways of oxalate biosynthesis and calcium oxalate formation.

On the petiolar structure of some Asplenium species

Petiolar characters of five species of Asplenium, viz., A. cheilosorum, A. dalhousiae, A. laciniatum, A. planicaule, and A. varians, have been investigated and their taxonomic significance is discussed. Petioles in A. varians receive a single vascular strand from the rhizome with two separate xylem strands, which during their upward course, unite to form a single xylem strand. In A. dalhousiae and A. laciniatum each petiole receives two widely separated vascular strands from the rhizome, which remain separate throughout the petiole. In A. cheilosorum and A. planicaule, the two separate vascular strands join each other within the petiole to form a single vascular strand. The shape of xylem strands in a transverse section in all the five species is distinctive.

Pinus haboroensis sp. nov. and the affinities of permineralized leaves from the Upper Cretaceous of Japan

A new species of Pinus is described based on permineralized needles from the Sankebetsugawa, Haboro, and the Koyanosawa, Ikushumbetsu, Mikasa City, Hokkaido, Japan. Leaf fragments were discovered in calcium carbonate nodules with abundant ammonites dated as Santonian–Senonian (Upper Cretaceous). The leaves, borne in fascicles of three or four, are 0.9–1.1 mm in radial and 1.5–1.8 mm in tangential diameters, and fragments up to 0.5 cm long have been recovered. The vascular strand is double and bundles are separated by a large anchor-shaped band of sclerenchyma fibers. Transfusion tissue up to four cells wide and a long-base triangular endodermis with an irregular outline surround the vascular tissues. Six to eight medial and external resin canals occur within the band of small plicate mesophyll cells three or four cells wide. The uniform hypodermis from one to four cells thick lies beneath thick-walled elliptical epidermal cells. These amphistomatic leaves with deeply sunken stomata most closely resemble those of Pinus coulteri D. Don, subgenus Pinus, section Pinus, subsection Sabinianae and have added significantly to our knowledge of permineralized Cretaceous pine needles. Pinus haboroensis sp. nov. is closely compared anatomically with the other Upper Cretaceous pines from Japan and North America and primitive needle characters are discussed. Emended diagnoses for P. flabellifolia Ogura and P. bifoliata Ueda and Nishida are presented, including a description of their possible affinities to sections and subsections of the genus Pinus.

The Internal Structure of Coir (Coconut) Fiber

The source of commercial coir fiber (actually, a vascular strand) is the massive fibrous husk (3-5 cm thick) surrounding the coconut. This paper reports a SEM study of some aspects of this interesting fiber. The specimens were sputter coated with Au Pd and observed with 4 KV accelerating voltage.A cut cross section of a retted coir fiber is seen in Figures 1 and 2. A high degree of porosity is apparent; a core of the vascular or conductive bundle is seen surrounded by a large area of elongated sclerenchymatous cells which are cemented together into a composite with pectins or hemicelluloses.The sclerenchymatous cells may be separated by a maceration process, in this work a dilute solution of sodium hypochlorite. A bent, partially macerated coir fiber showing the configuration and orientation of the cells is given in Figure 3. A completely separated cell showing its general shape and pits is shown in a light photomicrograph in Figure 4.

The primary vascular system and medullary bundle structure of Phytolacca dioica (Phytolaccaceae)

Phytolacca dioica has a primary vascular system which includes medullary bundles. The primary structure of these bundles is composite, consisting of two to four collateral vascular strands with their phloem poles oriented toward a common center. A cambium is formed between the xylem and phloem of the strands and extends to enclose the phloem of the whole bundle. After a period of cambial activity the medullary bundles become amphivasal. As is typical of species with helical phyllotaxy, the primary vascular system is organized into sympodia. The medullary bundles form the distal portions of the median leaf traces and continue in a medullary position for the number of nodes equal to the denominator of the phyllotactic fraction characterizing a given stem. As a medullary bundle passes out into a leaf, two or three vascular strands pass inward from the vascular cylinder to form a new medullary bundle. The number of medullary bundles in a stem is, thus, maintained. Variations of this pattern occur in the basal regions of juvenile shoots and in the basal and apical regions of adult flowering shoots. The relationship between leaf arrangement and the passing of vascular strand into the pith is discussed and a new classification of vascular systems with medullary bundles is proposed.