Stem anatomy of Apioideae (Apiaceae): effects of habit and reproductive strategy

Apioideae is the biggest and the most diverse of four subfamilies recognised within Apiaceae. Except for a few, likely derived, woody clades, most representatives of this subfamily are herbaceous. In the present study, we assessed stem anatomy of 87, mostly therophytic and hemicryptophytic, species from at least 20 distinct lineages of Apioideae, and juxtaposed them with 67 species from our previous anatomical projects also focused on this subfamily. Comparing our data with the literature, we found that wood anatomy does not allow for a distinction between apioids and their close relatives (Azorelloideae, Saniculoideae), but more distantly related Mackinlayoideae differ from Apioideae in their perforation plate type. Vessel element and fibre length, and vessel diameter were positively correlated with plant height: phenomena already reported in literature. Similar pattern was retrieved for vertical intervessel pit diameter. Wood ground tissue in apioids ranges from entirely fibrous to parenchymatous. The shortening of internodes seems to favour the formation of parenchymatic ground tissue, whereas the early shift to flowering promotes the deposition of fibrous wood in monocarpic species. These results support a hypothesis on interdependence among internode length, reproductive strategy, and wood ground tissue type.

Spatial regulation of thermomorphogenesis by HY5 and PIF4 in Arabidopsis

Plants respond to high ambient temperature by implementing a suite of morphological changes collectively termed thermomorphogenesis. Here we show that the above and below ground tissue-response to high ambient temperature are mediated by distinct transcription factors. While the central hub transcription factor, PHYTOCHROME INTERCTING FACTOR 4 (PIF4) regulates the above ground tissue response, the below ground root elongation is primarily regulated by ELONGATED HYPOCOTYL 5 (HY5). Plants respond to high temperature by largely expressing distinct sets of genes in a tissue-specific manner. HY5 promotes root thermomorphogenesis via directly controlling the expression of many genes including the auxin and BR pathway genes. Strikingly, the above and below ground thermomorphogenesis is impaired in spaQ. Because SPA1 directly phosphorylates PIF4 and HY5, SPAs might control the stability of PIF4 and HY5 to regulate thermomorphogenesis in both tissues. These data collectively suggest that plants employ distinct combination of SPA-PIF4-HY5 module to regulate tissue-specific thermomorphogenesis.

Micro-Anatomical Characterization of African Native Monotypic Genera - Anogeissus (DC.) Guill and Quisqualis Linn (Combretaceae)

This study was designed to explore the micro-anatomical characteristics of leaf and petiole of two unstudied West African native monotypic genera - Anogeissus and Qusqualis in Combretaceae with a view to characterizing the taxa, providing useful research-based information for identification. The samples were prepared following standard procedures. The light microscopic study of the transverse sections of the leaves in A. leiocarpus revealed a thick upper and lower cuticle while the cuticle on both leaf surfaces in Q. indica remain thin. The midrib vascular bundle of the leaf in Q. indica is characterized by arc-shape and starch grains were observed in the parenchyma cells of the ground tissue. The uniseriate rows of lamina epidermis were oval, squared, rectangular or polygonal in Q. indica while it was rectangular or slightly oval in A. leiocarpus. Vascular bundle in the leaves and petioles of both taxa were collateral. Simple, slender and short unicellular non-glandular trichomes were also observed in the leaf and petiole micro-anatomy of both taxa. It was concluded that the micro-anatomical features of the leaves and petioles are important parameters of characterization, used in the identification of the studied taxa.

Pharmacognostic and elemental analysis of the rhizome of C. spectabilis (Fenzl) Schumann (Costaceae)

The extract from the rhizome of Costus spectabilis (Costaceae) has been used to treat many illnesses including eye infections and cataract. The present study aimed to establish the pharmacognostic features of the rhizome by evaluating its macro-morphological characteristics, micro-morphological features using its anatomical section, physicochemical constants and elemental profile of its powder according to standard methods. Macro-morphology revealed features typical of a rhizome. Microscopical examination shows vascular bundles scattered throughout the ground tissue of starch-filled cellulosic parenchyma, parenchymatous cortex, endodermis and Oleoresin cells. Chemomicroscopy of the powder showed cellulosic cell walls, lignified cell walls, starch grains, fats and oil. The powder was found to have a moisture content of 12.3%, Total ash of 4.3%, acid insoluble ash of 2.0%, water soluble ash of 1.2%, water soluble extractive of 11.0% and alcohol soluble extractive of 6.5%. Elemental analysis showed the presence of Zn, Cu, Mg, Fe, Pb, Ni, Mn and Cd at concentrations of 24.62, 2.63, 1449.21, 113.23, 36.50, 31.90, 86.93 and 1.23 mg/kg in the powder respectively. The study has established some pharmacognostic features and elemental composition of the rhizome of C. spectabilis. The information could serve useful in providing quality control parameters and standardization of the crude drug. Keywords: Macro-morphology; Microscopical; Physico-chemical; Standardization; Elemental analysis

Ground tissue circuitry regulates organ complexity in cereal roots

Most plant roots have multiple cortex layers that make up the bulk of the organ and play key roles in physiology, such as flood tolerance and symbiosis. However, little is known about the formation of cortical layers outside of the highly reduced anatomy of the model Arabidopsis. Here we use single-cell RNAseq to rapidly generate a cell resolution map of the maize root, revealing an alternative configuration of the tissue formative SHORT-ROOT (SHR) signaling pathway adjacent to an expanded cortex. We show that maize SHR protein is hypermobile, moving at least eight cell layers into the cortex. Higher-order SHR mutants in both maize and Setaria have reduced numbers of cortical layers, showing that the SHR pathway controls expansion of cortical tissue in grasses that sets up anatomical complexity and a host of key traits.One sentence summarySingle-cell RNA-seq maps the maize root transcriptome uncovering a mechanism that regulates cortex layer number.

Foliar resistance to Rhizoctonia solani in Arabidopsis is compromised by simultaneous loss of ethylene, jasmonate and PEN2 mediated defense pathways

Rhizoctonia solani causes damaging yield losses on most major food crops. R. solani isolates belonging to anastomosis group 8 (AG8) are soil-borne, root-infecting pathogens with a broad host range. AG8 isolates can cause disease on wheat, canola and legumes, however Arabidopsis thaliana is heretofore thought to possess non-host resistance as A. thaliana ecotypes, including the reference strain Col-0, are resistant to AG8 infection. Using a mitochondria-targeted redox sensor (mt-roGFP2) and cell death staining, we demonstrate that both AG8 and a host isolate (AG2-1) of R. solani are able to infect A. thaliana roots. Above ground tissue of A. thaliana was found to be resistant to AG8 but not AG2. Genetic analysis revealed that ethylene, jasmonate and PENETRATION2-mediated defense pathways work together to provide resistance to AG8 in the leaves which subsequently enable tolerance of root infections. Overall, we demonstrate a significant difference in defense capabilities of above and below ground tissue in providing resistance to R. solani AG8 in Arabidopsis.

Comprehensive Pharmacognostical Profile of Drynaria quercifolia (L.) J. Sm.

Pteridophytes are gaining importance as therapeutic agents due to the presence of various phytochemicals and their promising bioactivities. Drynaria quercifolia (L.) J. Sm., a Polypodiaceae member is endowed with numerous medicinal properties and finds wide usage in ethno as well as traditional medicines. The rhizome of D. quercifolia (L.) J. Sm. was subjected to macro-microscopic, physicochemical, phytochemical and HPTLC analysis to derive a standard for this drug. The microscopic detailing showed a wavy outline due to the presence of ridges and furrows and a broad ground tissue with diffusely arranged steles. The powdered drug showed trichomes, stellar tissue and silica crystals while the physicochemical and phytochemical screenings gave substantial values of different parameters. The rhizome extracts were subjected to HPTLC studies with Linomat 5 TLC applicator and diagnostic peaks were recorded under UV 254 nm, 366 nm and 620 nm. The study put forward an exclusive identity profile of this medicinal rhizome.

BAM1/2 receptor kinase signaling drives CLE peptide-mediated formative cell divisions inArabidopsisroots

Cell division is often regulated by extracellular signaling networks to ensure correct patterning during development. InArabidopsis, the SHORT-ROOT (SHR)/SCARECROW (SCR) transcription factor dimer activatesCYCLIND6;1(CYCD6;1) to drive formative divisions during root ground tissue development. Here, we show plasma-membrane-localized BARELY ANY MERISTEM1/2 (BAM1/2) family receptor kinases are required forSHR-dependent formative divisions andCYCD6;1expression, but notSHR-dependent ground tissue specification. Root-enriched CLE ligands bind the BAM1 extracellular domain and are necessary and sufficient to activateSHR-mediated divisions andCYCD6;1expression. Correspondingly, BAM-CLE signaling contributes to the restriction of formative divisions to the distal root region. Additionally, genetic analysis reveals that BAM-CLE and SHR converge to regulate additional cell divisions outside of the ground tissues. Our work identifies an extracellular signaling pathway regulating formative root divisions and provides a framework to explore this pathway in patterning and evolution.

Macro and microscopic characters of Maerua oblongifolia (Forssk.) A. Rich leaf

The paper deals with a detailed investigation on the leaves of Maerua oblongifolia (Forssk.) A. Rich. which includes it’s morphological, anatomical and powder analysis. It is a low woody bushy under-shrub belonging to the family Capparaceae. The leaves are used in treatment of as fever, ear ache, stomach ache, skin infections, urinary calculii, diabetes mellitus, epilepsy, rigidity in lower limbs, and abdominal colic. The leaf amphistomatic, with mostly anamocytic, few tetracytic stomata. In transverse section of leaf is ribbed on either sides at midvein, epidermis one layered. Mesophyll differentiated into palisade and spongy tissues. Ground tissue of midvein differentiated into palisade, collenchyma and parenchyma. The midvien consists of one large oval shaped vascular bundles arranged are at the centre. Petiole in transverse section is circular adaxially small, grooved at centre and epidermis is having one layered, a single circular vascular bundle present at the centre, vascular bundle is enclosed by endodermis. The powder microscopic and organoleptic characters are also presented in this study. This study would helps as an appropriate source for authentification of the present studied drug.