Role and influence of soil microbial communities on plant invasion

It is known that plant invasions are of major concern as they result in loss of biodiversity and alterations in ecosystem processes and functions. Although numerous mechanisms have been postulated to find out the reasons behind plant invasiveness, the actual and precise mechanism is still obscure. Soil microbes are considered as one of the important determinants of plant growth and establishment. Plant invasion leads to changes in the composition and structure of soil microorganisms. Most of the earlier studies have focused on the aboveground mechanisms of plant invasion. Recently the belowground mechanisms for plant invasion are being investigated. In this review, we focus on the various hypotheses related to soil microbes in either enhancing or suppressing plant invasions. The interactions between soil microbes with native and non-native plant species, the role of the plant-soil feedback system in the invasion and its impact, the function of mycorrhizal and bacterial symbiosis in plant species invasion and the role of soil biota and changes brought about in soil nutrient cycling and soil enzymes due to plant invasion are also discussed

Ethnomedicinal importance of fern and fern allies traditionally used by tribal people of Palani Hills (Kodaikanal), Western Ghats, South India

Numerous studies have focused on the medicinal properties of angiosperms; however, only limited amountof studies have explored the medicinal potentials of fern and fern allies. The present study focuses on theethnomedicinal values of fern and fern allies that are traditionally used by the tribal people of Palani hills in SouthIndia through a survey of the area. In the present study, information on 50 species belonging to 35 genera in19 families were recorded for their medicinal values with their botanical name, family, habitat, and manner ofusing recipes have been recorded

Fungal associations in gametophytes and young sporophytic roots of the fern Nephrolepis exaltata

Information is limited on the presence of endophytic fungal associations in green gametophytes and young sporophytes of extant ferns. Nothing is known about their presence in Polypodiales, the largest order among extant ferns. We screened chlorophyllous gametophytes and young sporophytes of Nephrolepis exaltata (L.) Schott., (Lomariopsidaceae, Polypodiales) growing naturally on soil, brick and coir for the presence of fungal endophytes. Gametophytes and young sporophytes growing on different substrates were invariably colonized by septate endophytic fungi. Hyaline or brown, regularly septate, inter- or intracellular hyphae with moniliform cells or microsclerotia characterized septate endophytic fungi. However, only the roots of young sporophytes growing on soil and bricks harboured arbuscular mycorrhizal (AM) fungi. The AM morphology conformed to the intermediate type with intracellular hyphal coils, arbusculate coils and intercellular hyphae. No AM fungal spores could be retrieved from the soil on which gametophytes and young sporophytes were growing. The observations in this study support the idea that the septate fungal endophytes could confer an ecological advantage on colonized individuals, especially on nutrient deficient substrates

Root morphology and mycotrophy of Disperis neilgherrensis (Orchidaceae) from Western Ghats, southern India

Por primera vez se examinó la morfología radicular y la microtrofia de Disperis neilgherrensis Wight., provenientes de los Ghats occi- dentales, India meridional. El sistema radicula es disperso, consis- tiendo en una raices blancas delgadas de 0,28 ± 0,11 mm, que par- ten de un rizoma marrón. Las raíces están cubiertas por pelos radi- culares (19,2 ± 1,5 por mm de raíz) de 161,80 ± 12,68 μm de largo y 4,55 ± 1,17 μm de ancho. Las celulas corticales contenían es- tructuras fúngicas típicas de micorrizas orquidoides (OM) y arbus- culares (AM). En contraste, los rizomas sólo presentan estructuras OM. La colonización OM se caracteriza por presentar ovillos man- chados claros u obscuros, con hifas regularmente septadas de diá- metros variados. La colonización AM se caracteriza por ovillos hifa- les intracelulares no septados, arbúsculos y vesículas intracelula- res. El porcentaje de longitud con colonización OM fue de 56,51% para raíces y 73,64% para rizomas, mientras que la longitud de raíz con colonización AM fue de 30,23%. En tipo de AM en D. neil- gherrensis corresponde al tipo Paris

Endorrhizal fungal symbiosis in aroids of the Western Ghats, southern India

Information of dark septate endophyte (DSE), arbuscular mycorrhizal (AM), and fine root endophyte (FRE) fungal symbioses of aroids in the Western Ghats region are very low. Therefore, we assessed the endorrhizal symbiosis in 25 aroid species belonging to 16 genera of Araceae from six different locations of the Western Ghats. The results revealed co-occurrence of the DSE and AM symbiosis in all the examined aroids, and FRE presence in seven aroids (Alocasia ´ amazonica, Alocasia sp., Anthurium andraeanum, Epipremnum aureum, Spathiphyllum sp., Syngonium podophyllum, and Zantedeschia aethiopica). We found variance in root length having AM (inter and intracellular hyphae, arbuscules, vesicles and arbusculate coils) and DSE (melanized septate hyphae, microsclerotia, and moniliform hyphae) fungal structures. Moreover, the AM fungal morphology of Arum-Paris type was widespread, and intermediate type morphology reported for the first time in five aroids. AM fungi colonized the roots of Philodendron xanadu the most, followed by DSE in Caladium bicolor, and FRE in Spathiphyllum sp. AM fungal spores were present in all aroid soils examined. The percentage of root length comprising FRE hyphae was significantly and positively correlated root length with FRE arbuscules, AM fungal spore numbers and total colonization. Our study revealed that, the aroids tend to form associations with various endorrhizal fungi.

Vegetative anatomy and mycorrhizal morphology of Schoenorchis nivea (Lindl.) Schltr., (Orchidaceae) and their adaptive significance

The anatomical description of the vegetative parts (leaf, leaf sheath, stem and root) and mycorrhizal morphology of Schoenorchis nivea (Lindl.) Schltr., belonging to the subfamily Epidendroideae of Orchidaceae was investigated. Leaves were amphistomatic covered by 10-12 µm thick cuticle, stomata paracytic with small and irregular substomatal chambers. Mesophyll homogenous, composed of thin-walled chlorenchymatous cells. Banded water-storage cells abundant in the mesophyll and the largest vascular bundle occurred at the centre of the leaf. The leaf sheath has both adaxial and abaxial epidermis covered with cuticle, homogenous mesophyll, water-storage cells, raphides and vascular bundles. The stem is surrounded by a uniseriate epidermis, cortex consisting of thick-walled fibers and collateral vascular bundles scattered in the ground tissue. Cortical proliferation was evident in S. nivea stem. Root hairs present in root regions were in contact with the substratum. Root hairs frequently branched at their tips. Root possess 2-3 layered velamen, ∩-thickened exodermal cells, O-thickened uniseriate endodermis, and cortex of thin-walled parenchymatous cells containing raphides and water-storage cells. Cover cells present. Xylem arches are 9-11, with vascular tissues embedded in sclerenchymatous cells. Pith composed of thick-walled sclerenchymatous cells with intercellular space. The stomatal characteristics in leaf, the size of water-storage cells and vascular bundles exhibited significant variation in different plant parts. Intact and degenerating pelotons of orchid mycorrhizal fungi were observed in the root cortical cells. The observations of the present study clearly indicate that S. nivea possesses several anatomical adaptations to thrive in epiphytic habitats

Vegetative anatomy of Tabernaemontana alternifolia L. (Apocynaceae) endemic to southern Western Ghats, India

The anatomical description of vegetative parts of Taberenaemontana alternifolia L. belonging to the family Apocynaceae was investigated in the present study. The leaves of T. alternifolia is hypostomatic with paracytic stomata, uniseriate epidermis made up of thin-walled parenchymatous cells covered by thin cuticle on both adaxial and abaxial surfaces. The hypodermis comprises of angular collenchyma cells. Mesophyll is dorsiventral containing silica bodies and vascular bundles are bicollateral. The petiole is flattened adaxially and arch-shaped abaxially with a uniseriate epidermis covered by a thin cuticle. The hypodermis is 7-8 layered angular collenchyma cells consisting of laticifers and parenchymatic, cortical layers consisting of silica bodies and thick-walled fibers and U-shaped bicollateral vascular bundles. Secondary growth in stems is characterized by the formation of periderm and thick-walled fibers in the vascular tissues. Bicollateral vascular bundles are covered by sclerenchymatous patches, parenchymatous cortex and pith consist of fibers, laticifers and silica bodies. The root possess unicellular root hairs, compactly arranged thin-walled uniseriate epidermis, 16-18 layered cortex containing silica bodies and fibers, indistinct endodermis, radially arranged vascular bundles and 14-16 arched xylem. Pitted water-storage cells are present in the conjunctive tissue. Lignin deposition was observed in the root stelar region and pith is absent

Biological Role of Gellan Gum in Improving Scaffold Drug Delivery, Cell Adhesion Properties for Tissue Engineering Applications

Over the past few decades, gellan gum (GG) has attracted substantial research interest in several fields including biomedical and clinical applications. The GG has highly versatile properties like easy bio-fabrication, tunable mechanical, cell adhesion, biocompatibility, biodegradability, drug delivery, and is easy to functionalize. These properties have put forth GG as a promising material in tissue engineering and regenerative medicine fields. Nevertheless, GG alone has poor mechanical strength, stability, and a high gelling temperature in physiological conditions. However, GG physiochemical properties can be enhanced by blending them with other polymers like chitosan, agar, sodium alginate, starch, cellulose, pullulan, polyvinyl chloride, xanthan gum, and other nanomaterials, like gold, silver, or composites. In this review article, we discuss the comprehensive overview and different strategies for the preparation of GG based biomaterial, hydrogels, and scaffolds for drug delivery, wound healing, antimicrobial activity, and cell adhesion. In addition, we have given special attention to tissue engineering applications of GG, which can be combined with another natural, synthetic polymers and nanoparticles, and other composites materials. Overall, this review article clearly presents a summary of the recent advances in research studies on GG for different biomedical applications

Influencia del hongo arbuscular micorrícico en el crecimiento y arquitectura radicular en suelo tropical modificado con fosforita

Hemos ensayado la influencia del homgo micorrícizo arbuscular (AM) Scutellospora calospora en la estructura, crecimiento, asimilación de nutrientes, actividad fosfatasa y dependencia micorrizal de raíces de maíz por adicción de 0-5% de fosforita (RP) en suelos deficientes de fósforo (P). La adicción de RP aumentó significativamente la longitud total de la raíz, el número de raíces a diferentes niveles y el diámetro de los pelos radiculares de las plantas AM. El hongo AM influyó positivamente el crecimiento del maíz y la asimilación de nutrientes. Las actividades fosfatasa ácida y alcalina fueron mayores en las plantas AM en suelos mejorados. Al aumentar las concentraciones RP se redujeron no linealmente el porcentaje de colonización del hongo AM. Entonces, la inoculación de hongos AM junto a la mejora de fósfoso proveniente de RP podría sustituir fertilizantes químicos y hacer disponible el P proveniente de RP.Abstract We evaluated the influence of arbuscular mycorrhizal (AM) fungus Scutellospora calospora on root architecture, growth, nutrient uptake, root phosphatase activity and mycorrhizal dependency of maize in 0-5% rock phosphate (RP) amended phosphorus (P) deficient soil. RP amendment significantly increased total root length, number of roots in different orders, and root hair diameter of AM plants. The AM fungus positively influenced maize growth and nutrient uptake. Acid and alkaline phosphatase activities were higher for AM plants in RP amended soils. In contrast, increasing concentrations of RP reduced the percentage of AM fungus colonization non-linearly. Thus, AM fungus inoculation along with RP amendment could substitute chemical fertilizers and make available the P in RP to the plants