Ovule morphogenesis and structure in Menispermaceae,focusing on the development of the single fertile ovule and its systematic significance

Menispermaceae is one of the core groups of Ranunculales. The single fertile ovule in each ovary in Menispermaceae varies greatly in integument number, micropyle formation, and integument lobe. However, data regarding ovule morphogenesis in the family are very limited. In this study, we document ovule development of selected species in the Menispermaceae using scanning electron microscopy and light microscopy. Ovule development in Menispermaceae shows the following characteristics. Two ovules are initiated in a young carpel, one of them degenerates gradually and the other develops into a fertile ovule in subsequent stages. Bitegmic in Sinomenium Diels. and Cocculus DC. and unitegmic in Stephania Lour. The formation of unitegmy is probably due to integumentary shifting. The annularly initiated inner integument is of dermal origin and has 2–3 cell layers in the family, but the semi-annularly initiated outer integument is of both dermal and subdermal origin. Both inner and outer integument are cup-shaped at maturity. The cup-shaped outer integument is formed due to the outer integument's extension to the concave (adaxial) side of the funiculus. The obturator is well developed and consists of 2–3 cell layers in Cocculus or 9–11 cell layers in Stephania. Ovule development of Menispermaceae suggests some common characteristics between Cocculus and Sinomenium, and derived unitegmy supports molecular data that indicate Stephania is one of the late-diverging lineages in the family. Integument lobations are present. The sterile ovule shows variations in the degeneration process. These results will provide evidence for exploring the evolution of ovules in Ranunculales.     

Root pressure and specific conductivity in temperate lianas: exotic Celastrus orbiculatus (Celastraceae) vs. native Vitis riparia (Vitaceae)

The exotic temperate liana (woody vine) Celastrus orbiculatus has become a weed in Michigan, occurring in many of the same habitats as the native liana Vitis riparia. However, C. orbiculatus frequently develops into extensive monospecific infestations, while V. riparia does not. Freezing-induced embolism may be responsible for limiting liana distribution. Root pressure has been observed in numerous tropical lianas and temperate species of Vitis and has been implicated as vital to the recovery of xylem function in wide vessels following winter freezes. For both of these co-occurring lianas we investigated root pressure and water conductance as possible explanatory factors for their differential spread. According to our hypothesis, C. orbiculatus should have produced greater or more frequent root pressures than V. riparia. However, the reverse proved true, indicating that root pressure is not a prerequisite for weedy proliferation of C. orbiculatus. Additionally, the seasonal patterns of specific conductivity of stem xylem indicate that each species responds differently to environmental constraints. Vitis riparia establishes conductivity early in the growing season, before the leaves emerge, using root pressure to reverse embolism, but loses conductivity with the first freeze in early autumn. Celastrus orbiculatus is slow to establish conductivity, depending on new wood production, but leafs out sooner than V. riparia and maintains green leaves after the first freeze. Vulnerability curves of xylem to cavitation caused by water stress for the two species indicate that they respond similarly to dehydration. These results indicate that root pressures are not responsible for the invasive success of C. orbiculatus and suggest that other factors must be key to its prolific invasion.     

Four decades of old field vegetation development and the role of Celastrus orbiculatus in the northeastern United States

Abstract. This paper describes four decades of in situ vegetation change in a post-agricultural site in southern New England where the role of the introduced vine, Celastrus orbiculatus, has drastically modified the course of vegetation development. An initial perennial forb-grassland community was replaced by two strikingly different physiognomic vegetation types-an early hardwood forest and a vine community occupying the same site 40 yr later. This ecological phenomenon was unpredictable since Celastrus was not recorded at the site until the 1970s. Within the young hardwood forest dominated by Prunus serotina and Acer rubrum, a few old field species (five) persist, whereas 17 forest herbs have become established. Typical forest shrubs are rare or absent. The Celastrus-dominated vine community has suppressed or eliminated pre-existing growth to form a relatively stable community where a forest vegetation is the regional vegetation type. Celastrus also appears to be facilitating a native vine (Vitis labrusca) by forming a ‘ladder’ for its advance. Although A. rubrum and Quercus spp. could ultimately dominate the forest community, the contiguous and aggressive nature of Celastrus makes predictions questionable. This long-term study highlights the unpredictable nature of old field succession and the role of an exotic species in threatening the natural vegetation development.     

A New Stain for Pollen Fertility Studies

The juice from the berries of Cocculus hirsutum was extracted and used for pollen fertility studies in various crops. Two stains were prepared: P. H. Ramanjini (PHR) stain and modified PHR stain. The modified PHR stain contains lactic acid and produces the best staining differentiation. The intensity of the staining was dependent on the thickness of the pollen cell walls, hence PHR stain is recommended for thick walled pollen grains and the modified PHR stain for pollen with relatively thin walls. The preparation of both the stains are very simple, quick and inexpensive.     

Cocculus hirsutus extract inhibits the Xanthomonas oryzae pv. oryzae,the bacterial leaf blight pathogen in rice

Plant-derived natural bactericides and their possible applications in agriculture to control plant bacterial diseases has intensified as this approach has enormous potential to inspire and influence modern agro-chemical research. Naturally occurring and biologically active plant products such as essential oils and organic extracts could be a source of alternative classes of natural biopesticides to serve as templates for new and more effective compounds in controlling plant pathogenic micro-organisms. In the present study, the efficacy of six plants extracts from different solvent system were tested for their antibacterial activity aganist Xanthomonas oryzae pv. oryzae both in vitro and in vivo. Among these extracts, Cocculus hirsutus leaf chloroform extract exhibits significant antibacterial activity against X. oryzae pv. oryzae. Data obtained from the experiments such as minimum inhibitory concentration, effect of C. hirsutus leaf chloroform extract on the incidence of X. oryzae pv. oryzae, phytotoxicity test and effect of C. hirsutus leaf chloroform extract on seed germination and seedling vigour, along with the in vivo experiments under greenhouse conditions showed significant improvement over controls. Thus, the present study demonstrated that the C. hirsutus leaf chloroform extract posses antibacterial activity against bacterial leaf blight pathogen of rice.     

《本草图经》兴化军防己的本草考证

对《本草图经》中兴化军防己的附图及文字记载进行本草考证,探究其原植物品种。通过古今文献考证和植物学比较研究,从植物形态、药材性状、产地分布及性味功用等方面进行分析,认为《本草图经》中的兴化军防己应为今之防己科植物木防己[Cocculus orbiculatus (L.) DC.],为防己类中药的古今品种沿革及基原考证提供参考。     

Ecological significance of wood anatomy in two lianas from arid southwestern Saudi Arabia

The hot and arid lowlands of southwestern Saudi Arabia are home to two common lianas, Cocculus pendulus and Leptadenia arborea. This paper attempts to relate the adaptation of these two climbing woody perennials to such a harsh environment to the anatomy and hydraulic characteristics of their wood. The stems of these lianas have wood with wide xylem vessels and high hydraulic conductivity which should enhance water flow to the upper canopy despite their severe twisting. Hydraulic conductivity is further helped by the simple perforation plates of xylem vessels. The circular thickening of xylem walls gives them strength and reduces the risk of their collapse and the ensuing embolism in the advent of high tension created by severe water deficit and high evapo-transpiration demand. Wide vessels, on the other hand, are more susceptible to embolism. This problem may be overcome by reducing the solute potential of xylem sap by hydrolysis of starch grains which were found to be abundant in the vicinity of the vessels. This should help absorb water by the deep roots from the capillary fringes of the typically shallow water table in this particular habitat. Furthermore, the abundance of ray parenchyma cells between xylem groups of both lianas provides great flexibility with minimum damage to water conduits in the stem during climbing and twisted growth. It was concluded that these wood features in both lianas are crucial for survival under the harsh conditions of arid Tihama plains of southwestern Saudi Arabia.     

南蛇藤原生质体培养及植株再生

以4℃低温暗处理24 h的南蛇藤胚性愈伤组织为分离原生质体的原材料,用MS培养基进行液体浅层静置、固液双层以及琼脂糖包埋培养原生质体,获得再生愈伤组织并分化成苗,建立了原生质体培养体系。结果表明,低温暗处理利于高产率高质量原生质体的获得;0.5%纤维素酶+0.5%果胶酶+5 mmol.L-1MES为酶的最佳配方;12 h为最佳酶解时间;13%为甘露醇最佳浓度;静置12 h+振荡0.5 h为最佳酶解方式;液体浅层静置培养取得了较好的原生质体培养效果;MS+6-BA2.0 mg.L-1+IBA 0.1 mg.L-1为愈伤组织最佳分化培养基;1/2MS+NAA0.1 mg.L-1为最佳生根培养基。     

基于RNA-seq对南蛇藤MADS-box转录因子序列及表达分析

为了分析南蛇藤MADS-box转录因子对其雌花发育和果实形成的调控信息,本文基于南蛇藤的转录组数据,获得15个具有全长开放阅读框的MADS-box转录因子（ColMADS）,并利用生物信息学方法对其性质和结构特性进行了分析。结果表明,基因comp37814_g1和comp41380_g2属于M-type家族,不含有K盒结构,其他均为MIKC家族;除了comp37713_g1之外,其余均属于不稳定的亲水性蛋白;二级结构均含有α-螺旋、扩展链结构、β-转角和无规则卷曲,其中α-螺旋所占比例最高;序列主要包含5种保守基序,基序1和基序2分别含50个氨基酸且属于该基因家族的保守基序,仅基序1含有MADS盒。系统进化分析结果显示南蛇藤ColMADS转录因子被分为10个进化支,分属于不同类型的亚家族及不同的组。另外,利用荧光定量PCR检测方法揭示了这些基因在南蛇藤盛花、落花和幼果不同发育时期的表达情况。结果表明,2个基因在盛花期相对表达值最高,9个基因在落花期相对表达值最高,在幼果形成过程中有4个基因显著上调表达。     

Seed and fruit anatomy ofCocculus hirsutus (Menispermaceae)

The ovules ofCocculus hirsutus are anatropous, bitegmic and, crassinucellate. The fruit is drupaceous, black purple, and laterally compressed and has a pericarp demarcated into exocarp and endocarp. The seeds are curved around the basal bodies. Testa and tegmen cells are thin-walled and unspecialized. In the ripe seed the inner epidermis of the tegmen persists, whereas the entire testa and the outer layer of the tegmen degenerate. Relationships of theMenispermaceae toRanunculaceae, Berberidaceae, andLardizabalaceae are supported.