Micro-morpho-anatomical transitions at various stages of in vitro development of Crinum malabaricum Lekhak and Yadav: A critically endangered medicinal plant.

Crinum malabaricum Lekhak & Yadav is a recently discovered and critically endangered aquatic bulbous plant of the family Amaryllidaceae. It gained attention as a wild source of the acetylcholinesterase inhibiting alkaloid 'galanthamine' used to treat Alzheimer and Parkinson diseases. The bulbs of this plant contain the highest amount of galanthamine among Crinum species. In vitro regeneration systems were developed to produce quality uniform plantlets of C. malabaricum. Bright field light microscopy was used to analyse micro-morpho-anatomical developments taking place in the leaves and roots during in vitro, ex vitro and in vivo transitions of plantlets. Leaves and roots of plants raised in vitro possessed a higher degree of microscopic structural anomalies, such as underdeveloped epicuticular wax deposition, immature and non-functional stomata, more aquiferous parenchyma with a reduced lumen. Roots developed in vitro were characterized by extremely large, uneven cortical cells and reduced intercellular spaces. The vascular tissues were under-developed and only primary vascular tissues were observed. As a result of ex vitro acclimation, there was a significant acceleration in the improvement of tissue systems in leaves and roots. Such plantlets can tolerate elevated temperatures and light under in vivo conditions. Thus, the microscopic evaluation of the structural trajectory in different stages of plantlet development provides an understanding of the acclimation process and structural adaptations, which could help enhance survival of in vitro raised plantlets under ex vitro and in vivo conditions.

The battle of two ions: Ca2+ signalling against Na+ stress.

Soil salinity adversely affects plant growth, crop yield and the composition of ecosystems. Salinity stress impacts plants by combined effects of Na+ toxicity and osmotic perturbation. Plants have evolved elaborate mechanisms to counteract the detrimental consequences of salinity. Here we reflect on recent advances in our understanding of plant salt tolerance mechanisms. We discuss the embedding of the salt tolerance-mediating SOS pathway in plant hormonal and developmental adaptation. Moreover, we review newly accumulating evidence indicating a crucial role of a transpiration-dependent salinity tolerance pathway, that is centred around the function of the NADPH oxidase RBOHF and its role in endodermal and Casparian strip differentiation. Together, these data suggest a unifying and coordinating role for Ca2+ signalling in combating salinity stress at the cellular and organismal level.

Calcium Signaling during Salt Stress and in the Regulation of Ion Homeostasis.

Soil composition largely defines the living conditions of plants and represents one of their most relevant, dynamic and complex environmental cues. The effective concentrations of many either tolerated or essential ions and compounds in the soil usually differ from the optimum that would be most suitable for plants. In this regard, salinity - caused by excess of NaCl - represents a widespread adverse growth condition but also shortage of ions like K+, NO3- and Fe2+ restrains plant growth. During the past years many components and mechanisms that function in the sensing and establishment of ion homeostasis have been identified and characterized. Here, we reflect on recent insights that extended our understanding of components and mechanisms, which govern and fine-tune plant salt stress tolerance and ion homeostasis. We put special emphasis on mechanisms that allow for interconnection of the salt overly sensitivity pathway with plant development and discuss newly emerging functions of Ca2+ signaling in salinity tolerance. Moreover, we review and discuss accumulating evidence for a central and unifying role of Ca2+ signaling and Ca2+ dependent protein phosphorylation in regulating sensing, uptake, transport and storage processes of various ions. Finally, based on this cross-field inventory, we deduce emerging concepts and arising questions for future research.

New generic and species records for the flora of Saudi Arabia.

Recent field works in the central and southern regions of Saudi Arabia including agricultural centers have managed to collect four vascular plants new to terrestrial and wetland flora of the country. These new additions include one new genus Malvastrum A. Gray (M. coromandelianum) subsp. capitato-spicatum (O. Kuntze) S.R. Hill, Potamogeton perfoliatus L. (Potamogetonaceae), Euphorbia tirucalli L. (Euphorbiaceae) and Sesuvium portulacastrum (L.) L. (Aizoaceae). Detailed morphological description, distribution and habitat of each of these species are provided along with illustrations and photographs. The report of new additions to the flora of Saudi Arabia indicated that the country needs thorough botanical explorations.

Simple and rapid protocol for the isolation of PCR-amplifiable DNA from medicinal plants.

Medicinal plant species has a valuable economic importance because of its usage as pharmaceuticals, nutritional, as well as its use in popular medication. For DNA-based techniques, nanogram quantities of the purified DNA are requisite to amplify and yield sufficient amounts of PCR products. SDS-based DNA isolation method was used to extract DNA from 11 species of different aromatic and medicinal plants collected from Saudi Arabia. Three hundred milligrams of fresh shredded plant material was necessary. The DNA purity was further confirmed by agarose gel, restriction endonuclease digestion and microsatellite primed-polymerase chain reaction (MP-PCR). DNA yields ranged from 10-20 µg (in 100-µL elution volumes) from all plant material evaluated. The DNA obtained was free of any contaminating proteins, polysaccharides and colored pigments. The extracted genomic DNA was found suitable for restriction digestion and PCR amplification. Our experimental procedure provides an easy, suitable, non-toxic, cheap, and quick process for the amplification of DNA from medical plant tissue.