Structure of the unusual explosive fruits of the early diverging angiosperm Illicium (Schisandraceae s.l., Austrobaileyales)

All Illicium spp. have explosive fruits, which is a unique character among the basal grade of angiosperms. Illicium fruits consist of several ventrally dehiscing follicles developing from conduplicate carpels, with a prominent, slightly postgenitally fused ventral slit. The closure of the ventral slit is also secured by two mirror‐symmetrical massive longitudinal sclerenchymatous bands in the mesocarp along the edges and by turgor pressure. The pericarp differentiates into a fleshy (or coriaceous) peripheral zone (exocarp and mesocarp) with numerous ethereal‐oil‐containing cells and a sclerenchymatous (single‐layered, palisade) inner zone (endocarp). Dehydration of the fleshy zone of the pericarp and partial compression of the epidermal sclereids with U‐shaped wall thickenings lining the ventral suture are instrumental in explosive fruitlet dehiscence. Generally, the fruit structure of Illicium differs dramatically from those in other early diverging angiosperms. Gynoecium and fruit structure (and a probable early Cretaceous divergence from the Schisandra‐Kadsura clade) provide evidence for treatment of Illicium as separate from Schisandraceae s.s. © 2013 The Linnean Society of London, Botanical Journal of the Linnean Society, 2013 , 171 , 640–654.     

The diversity of anther structures and dehiscence patterns among Hamamelididae

HUFFORD, L. D. & ENDRKSS, P. K., 1989. The diversity of anther structures and dehiscence patterns among Hamamelididae. This survey of anther structures and dehiscence patterns focuses on the range of diversity among extant Hamamelididae. The definition and structure of the anther stomium are considered in detail to provide a basis for characterizing dehiscence patterns. We are concerned particularly with the structural basis and distribution of so-called valvate dehiscence, which we define here as occurring only in those anthers that possess stomial bifurcations or markedly eccentric stomia. Valvate dehiscence is restricted to Trochodendrales and Hamamelidales among Hamamelididae, although some Hamamelidaceae possess only linear, not markedly eccentric stomia that lead to longitudinal dehiscence patterns. Anther forms are somewhat variable and do not appear to be highly correlated with stomial patterns, although stomial bifurcations occur most frequently in anthers with broad, thick connectives that extend for the full length (or nearly so) of the thecae. Valvate dehiscence usually occurs in anthers in which the pollen sacs are embedded in bulky superficial tissues. An evolutionarily secondary extension of the stomium around the thecal shoulders seems to have occurred in taxa with a nonextensive connective and may facilitate a broader anther opening in cases of longitudinal dehiscence. An endothecial-like connective hypodermis is a notable characteristic among examined 'Lower Hamamelididae' (except Disanthus) and is also present in Daphnipfiyllum and Eucommia. We hypothesize that this specialized connective hypodermis facilitates a broader opening of the anther.     

Mitral annuloplasty ring flexibility preferentially reduces posterior suture forces

Annuloplasty ring repair is a common procedure for the correction of mitral valve regurgitation. Commercially available rings vary in dimensions and material properties. Annuloplasty ring suture dehiscence from the native annulus is a catastrophic yet poorly understood phenomenon that has been reported across ring types. Recognizing that sutures typically dehisce from the structurally weaker posterior annulus, our group is conducting a multi-part study in search of ring design parameters that influence forces acting on posterior annular sutures in the beating heart. Herein, we report the effect of ring rigidity on suture forces. Measurements utilized custom force sensors, attached to annuloplasty rings and implanted in normal ovine subjects via standard surgical procedure. Tested rings included the semi-rigid Physio (Edwards Lifesciences) and rigid and flexible prototypes of matching geometry. While no significant differences due to ring stiffness existed for sutures in the anterior region, posterior forces were significantly reduced with use of the flexible ring (rigid: 1.95 ± 0.96 N, semi-rigid: 1.76 ± 1.19 N, flexible: 1.04 ± 0.63 N; p < 0.001). The ratio of anterior to posterior F_C scaled positively with increasing flexibility (p < 0.001), and posterior forces took more time to reach their peak load when a flexible ring was used (p < 0.001). This suggests a more rigid ring enables more rapid/complete force equilibration around the suture network, transferring higher anterior forces to the weaker posterior tissue. For mitral annuloplasties requiring ring rigidity, we propose a ring design concept to potentially disrupt this force transfer and improve suture retention.     

Floral anatomy and morphology in thePolygalaceae

Floral morphology and anatomy of 15 genera in thePolygalaceae have been studied. The pentamerous origin of the polygalaceous flower is confirmed and shown to apply to all genera in the family. The keel is interpreted as a single petal, and the androecium as of bimeric origin. Vascular structure in the receptacles ofCarpolobia andMonnina subg.Monnina is described in detail, and a compilation of results, focusing on the vascular supply for the androecium and gynoecium, is given for all genera. Based on similarities and differences in vascularization it is concluded that present taxonomy, in particular the tribal system, needs to be reviewed.     

Sigmoid sinus cortical plate dehiscence induces pulsatile tinnitus through amplifying sigmoid sinus venous sound

Sigmoid sinus cortical plate dehiscence (SSCPD) is common in pulsatile tinnitus (PT) patients, and is treated through SSCPD resurfacing surgery in clinic, but the bio-mechanism is not clear as so far. This study aimed to clarify the bio-mechanism of PT sensation induced by SSCPD, and quantify the relationship of cortical plate (CP) thickness and PT sensation intensity. It was hypothesized that SSCPD would induce PT through significantly amplifying sigmoid sinus (SS) venous sound in this study. Finite element (FE) analysis based on radiology data of typical patient was used to verify this hypothesis, and was validated with clinical reports. In cases with different CP thickness, FE simulations of SS venous sound generation and propagation procedure were performed, involving SS venous flow field, vibration response of tissue overlying dehiscence area (including SS vessel wall and CP) and sound propagation in temporal bone air cells. It was shown in results that SS venous sound at tympanic membrane was 56.9 dB in SSCPD case and −45.2 dB in intact CP case, and was inaudible in all thin CP cases. It was concluded that SSCPD would directly induce PT through significantly amplifying SS venous sound, and thin CP would not be the only pathophysiology of PT. This conclusion would provide a theoretical basis for the design of SSCPD resurfacing surgery for PT patients with SSCPD or thin CP.     

Action of jasmonates in plant stress responses and development — Applied aspects

Jasmonates (JAs) are lipid-derived compounds acting as key signaling compounds in plant stress responses and development. The JA co-receptor complex and several enzymes of JA biosynthesis have been crystallized, and various JA signal transduction pathways including cross-talk to most of the plant hormones have been intensively studied. Defense to herbivores and necrotrophic pathogens are mediated by JA. Other environmental cues mediated by JA are light, seasonal and circadian rhythms, cold stress, desiccation stress, salt stress and UV stress. During development growth inhibition of roots, shoots and leaves occur by JA, whereas seed germination and flower development are partially affected by its precursor 12-oxo-phytodienoic acid (OPDA). Based on these numerous JA mediated signal transduction pathways active in plant stress responses and development, there is an increasing interest in horticultural and biotechnological applications. Intercropping, the mixed growth of two or more crops, mycorrhization of plants, establishment of induced resistance, priming of plants for enhanced insect resistance as well as pre- and post-harvest application of JA are few examples. Additional sources for horticultural improvement, where JAs might be involved, are defense against nematodes, biocontrol by plant growth promoting rhizobacteria, altered composition of rhizosphere bacterial community, sustained balance between growth and defense, and improved plant immunity in intercropping systems. Finally, biotechnological application for JA-induced production of pharmaceuticals and application of JAs as anti-cancer agents were intensively studied.     

硅对水稻籼粳杂种雌雄配子育性和结实率的影响

以2个籼稻品种和2个粳稻品种及其籼粳杂种一代为材料,通过水培试验研究了硅对籼粳亚种间杂种雌雄配子育性和结实率的影响。结果表明:4个水稻亲本的育性正常,而亚种间杂种‘台中65’/‘广陆矮4号’和‘穞稻’/‘秋光’F1花粉育性分别为40.1%和50.3%,小穗育性分别为25.8%和40.3%;其F1胚囊具有正常的卵细胞、助细胞、极核及反足细胞,胚囊败育率分别为5.33%和3.33%。加硅处理F1每个柱头上花粉粒多于25粒的小花数分别占90%和90.5%,而不加硅处理高于20粒的小花数仅占8%和10%;加硅处理F1花粉离体萌发率分别为75.15%和76.23%,小穗的结实率分别达到65.5%和68.7%,而不加硅处理的分别为46.7%和48.13%,小穗结实率分别只有25.8%和40.3%,且加硅处理极显著高于不加硅处理。研究表明,水稻籼粳杂种存在半不育现象,并主要由花粉半不育和花药开裂性差造成;硅肥能促进杂种F1植株的花药开裂,明显增加柱头上花粉粒数目,并促进花粉萌发,显著提高小穗的结实率。     

Morphological and anatomical studies on fruits of Veronica from south-west Spain

Following examination by scanning electron and light microscope of the fruit features of 12 species of Veronica from south-west Spain, morphological and anatomical studies revealed that these taxa can be differentiated on the basis of these features. Phenetic analysis with 28 characters additionally revealed several groups of species in Veronica to be closely related on the basis of their seed morphology. A key distinguishing the different taxa is provided. Finally, dehiscence mechanisms are briefly discussed.     

Notes on the capsule dehiscence inAcanthophyllum (Caryophyllaceae) and allied genera

The shape and the mode of dehiscence of the capsule had been regarded as good differential characters betweenAcanthophyllum and related genera.—Studies of these characters, including the shape of the ovary, in species ofAcanthophyllum, Diaphanoptera, Ochotonophila andScleranthopsis show, however, that they cannot be used as differential characters for the genusAcanthophyllum. Dedicated to Prof.K. H. Rechinger on the occasion of his 80th birthday.