Stomata exert control on fluxes of CO2 and water (H2 O) in the majority of vascular plants and thus are pivotal for planetary fluxes of carbon and H2 O. However, in mosses, the significance and possible function of the sporophytic stomata are not well understood, hindering understanding of the ancestral function and evolution of these key structures of land plants. Infrared gas analysis and 13 CO2 labelling, with supporting data from gravimetry and optical and scanning electron microscopy, were used to measure CO2 assimilation and water exchange on young, green, ± fully expanded capsules of 11 moss species with a range of stomatal numbers, distributions, and aperture sizes. Moss sporophytes are effectively homoiohydric. In line with their open fixed apertures, moss stomata, contrary to those in tracheophytes, do not respond to light and CO2 concentration. Whereas the sporophyte cuticle is highly impermeable to gases, stomata are the predominant sites of 13 CO2 entry and H2 O loss in moss sporophytes, and CO2 assimilation is closely linked to total stomatal surface areas. Higher photosynthetic autonomy of moss sporophytes, consequent on the presence of numerous stomata, may have been the key to our understanding of evolution of large, gametophyte-independent sporophytes at the onset of plant terrestrialization.

Several hundred genes are required for embryonic and gametophytic development in the model plant Arabidopsis thaliana, as inferred from the lethality of their mutations. Despite many of these genes are expressed throughout the plant life cycle, the corresponding mutants arrest at early stages, preventing the study of their post-embryonic functions by conventional methods. Clonal analysis represents an effective solution to this problem by uncovering the effects of embryo-lethal mutations in sectors of mutant cells within an otherwise normal adult plant. In this pilot study, we have evaluated the suitability of two sector induction methods for the large-scale study of the post-embryonic effects of embryo-lethal (emb) mutations in Arabidopsis. In line with the interests of our laboratory, we selected 24 emb mutations that damage genes that are expressed in wild-type vegetative leaves but whose effects on leaf development remain unknown. For the induction of mutant sectors in adult plants, we followed one approach based on the X-ray irradiation of \'cell autonomy\' (CAUT) lines, and another based on the site-specific excision of transgenes mediated by Cre recombinase. We conclude that both methods are time-consuming and difficult to scale up, being better suited for the study of emb mutations on a case-by-case basis.

Recent advances in fluorescence-based staining of cellular compartments coupled with confocal microscopy imaging have allowed the visualization of three-dimensional (3D) structures with cellular resolution in various intact plant tissues and species. Such approaches are of particular interest for the analysis of the reproductive lineage in plants including the meiotic precursor cells deeply embedded within the ovary of the gynoecium enclosed in the flower. Yet, their relative inaccessibility and the lack of optical clarity of plant tissues prevent robust staining and imaging across several cell layers. Several whole-mount tissue staining and clearing techniques are available. One of them specifically allows staining of cellular boundaries in thick tissue samples while providing extreme optical clarity, using an acidic treatment followed by a modified Pseudo-Schiff propidium iodide (mPS-PI) method. While commonly used for Arabidopsis tissues, its application to other species like the model crop rice required protocol adaptations for obtaining robust staining that we present here. The procedure comprises six steps: (a) Material sampling; (b) Material fixation; (c) Tissue preparation; (d) Staining; (e) Sample mounting; and (d) Microscopy imaging. Particularly, we use ethanol and acetic anhydride as fixative reagents. A modified enzymatic treatment proved essential for starch degradation influencing optical clarity hence allowing acquisition of images at high resolution. This improved protocol is efficient for analyzing the megaspore mother cells in rice (Oryza sativa) ovary but is broadly applicable to other crop tissues of complex composition, without the need for tissue sectioning.

CONCLUSIONS: Tetraploid clementine displays mainly tetrasomic inheritance. Genetic structures of 2n SDR and 2 × gametes from DD clementine are complementary and will guides triploids citrus breeding strategies. Triploid breeding is developed worldwide to create new seedless cultivars. Citrus triploid hybrids can be recovered from 2x × 2x sexual hybridizations as a consequence of the formation of unreduced gametes (2n), or from 4x × 2x interploid hybridizations in which tetraploid parents used are most often doubled-diploid (DD). Here we have analyzed the inheritance in doubled-diploid clementine and compared the genetic structures of gametes of DD clementine with SDR unreduced gametes of diploid clementine. Parental heterozygosity restitution (PHR) with DD parents depends on the rate of preferential chromosome pairing and thus the proportion of disomic versus tetrasomic segregations. Doubled-diploid clementine largely exhibited tetrasomic segregation. However, three linkage groups had intermediate segregation and one had a tendency for disomy. Significant doubled reduction rates (DR) rates were observed in six of the nine LGs. Differences of PHR between 2n SDR and 2x DD gametes were highest in the centromeric region and progressively decreased toward the distal regions where they were not significant. Over all markers, PHR was lower (two-thirds) in SDR 2n gametes than in DD-derived diploid gametes. The two strategies appear complementary in terms of genotypic variability. Interploid 4x × 2x hybridization is potentially more efficient for developing new cultivars that are phenotypically closer to the diploid parent of the DD than sexual hybridization through SDR 2n gametes. Conversely, 2x × 2x triploidisation has the potential to produce novel products with characteristics for market segmentation strategies.

Identifying natural variation of health-promoting compounds in staple crops and characterizing its genetic basis can help improve human nutrition through crop biofortification. Some varieties of sorghum, a staple cereal crop grown worldwide, have high concentrations of proanthocyanidins and 3-deoxyanthocyanidins, polyphenols with antioxidant and anti-inflammatory properties. We quantified total phenols, proanthocyanidins, and 3-deoxyanthocyanidins in a global sorghum diversity panel (n = 381) using near-infrared spectroscopy (NIRS), and characterized the patterns of variation with respect to geographic origin and botanical race. A genome-wide association study (GWAS) with 404,628 SNP markers identified novel quantitative trait loci for sorghum polyphenols, some of which colocalized with homologues of flavonoid pathway genes from other plants, including an orthologue of maize (Zea mays) Pr1 and a homologue of Arabidopsis (Arabidopsis thaliana) TT16. This survey of grain polyphenol variation in sorghum germplasm and catalog of flavonoid pathway loci may be useful to guide future enhancement of cereal polyphenols.

Recently the safety of Heshouwu become a focus, but the reasons of its hepotoxicity are confused. On the basis of literature research, some findings on species and usage custom maybe supply some clues to explain the reasons of its hepotoxicity. Heshouwu had red Heshouwu (male) and white Heshouwu (female) in ancient literature, and traditional usage was use of the male and female together. The Latin name of red Heshouwu is Fallopia multiflora, and that of the white one is F. multiflora var. multiflora.

Patch-clamp studies carried out on the tonoplast of the moss Physcomitrella patens point to existence of two types of cation-selective ion channels: slowly activated (SV channels), and fast-activated potassium-selective channels. Slowly and instantaneously saturating currents were observed in the whole-vacuole recordings made in the symmetrical KCl concentration and in the presence of Ca(2+) on both sides of the tonoplast. The reversal potential obtained at the KCl gradient (10 mM on the cytoplasmic side and 100 mM in the vacuole lumen) was close to the reversal potential for K(+) (E K), indicating K(+) selectivity. Recordings in cytoplasm-out patches revealed two distinct channel populations differing in conductance: 91.6 ± 0.9 pS (n = 14) at -80 mV and 44.7 ± 0.7 pS (n = 14) at +80 mV. When NaCl was used instead of KCl, clear slow vacuolar SV channel activity was observed both in whole-vacuole and cytoplasm-out membrane patches. There were no instantaneously saturating currents, which points to impermeability of fast-activated potassium channels to Na(+) and K(+) selectivity. In the symmetrical concentration of NaCl on both sides of the tonoplast, currents have been measured exclusively at positive voltages indicating Na(+) influx to the vacuole. Recordings with different concentrations of cytoplasmic and vacuolar Ca(2+) revealed that SV channel activity was regulated by both cytoplasmic and vacuolar calcium. While cytoplasmic Ca(2+) activated SV channels, vacuolar Ca(2+) inhibited their activity. Dependence of fast-activated potassium channels on the cytoplasmic Ca(2+) was also determined. These channels were active even without Ca(2+) (2 mM EGTA in the cytosol and the vacuole lumen), although their open probability significantly increased at 0.1 μM Ca(2+) on the cytoplasmic side. Apart from monovalent cations (K(+) and Na(+)), SV channels were permeable to divalent cations (Ca(2+) and Mg(2+)). Both monovalent and divalent cations passed through the channels in the same direction-from the cytoplasm to the vacuole. The identity of the vacuolar ion channels in Physcomitrella and ion channels already characterised in different plants is discussed.

OBJECTIVE: The maternal gametophytic calyptra is critical for moss sporophyte development and ultimately sporogenesis. The calyptra has been predicted to protect the sporophyte apex, including the undifferentiated sporogenous region and seta meristem, from desiccation. We investigate the hypothesis that this waterproofing ability is due to a waxy cuticle. The idea that moss calyptrae are covered by a cuticle has been present in the literature for over a century, but, until now, neither the presence nor the absence of a cuticle has been documented for any calyptra.
METHODS: The epidermis of the calyptra, leafy gametophyte and sporophyte sporangia of the moss Funaria hygrometrica were examined using scanning and transmission electron microscopy. Thicknesses of individual cuticle layers were quantified and compared statistically. The immunochemistry antibody (LM19) specific for pectins was used to locate cell wall material within the cuticle.
RESULTS: A multi-layered cuticle is present on the calyptra of F. hygrometrica, including layers analogous to the cuticular layer, cell wall projections, electron-lucent and electron-dense cuticle proper observed in vascular plants. The calyptra rostrum has a cuticle that is significantly thicker than the other tissues examined and differs by specialized thickenings of the cuticular layer (cuticular pegs) at the regions of the anticlinal cell walls. This is the first documentation of cuticular pegs in a moss.
CONCLUSIONS: The calyptra and its associated cuticle represent a unique form of maternal care in embryophytes. This organ has the potential to play a critical role in preventing desiccation of immature sporophytes and thereby may have been essential for the evolution of the moss sporophyte.