Transmission of sugarcane white leaf phytoplasma by Yamatotettix flavovittatus, a new leafhopper vector

Sugarcane white leaf disease is caused by plant pathogenic phytoplasmas that are transmitted to the plant by the leafhopper Matsumuratettix hiroglyphicus (Matsumura). To determine whether there are other insect vectors that transmit this disease pathogen, leafhopper species in sugarcane, Saccharum officinarum L., fields in northeastern Thailand were monitored by using light traps. Sixty-nine leafhopper species from family Cicadellidae were found. Using nested polymerase chain reaction (PCR) with specific primers, a 210-bp amplified DNA fragment corresponding to phytoplasma associated with sugarcane white leaf disease was detected from 12 species of leafhoppers [Balclutha rubrostriata (Melichar), Balclutha sp., Bhatia olivacea (Melichar), Exitianus indicus Distant, Macrosteles striifrons Anufriew, Matsumuratettix hiroglyphicus (Matsumura), Recilia distincta (Motschulsky), Recilia dorsalis (Motschulsky), Recilia sp., Thaia oryzivora Ghauri, Yamatotettix flavovittatus Matsumura, and Xestocephalus sp.]. The percentage of individual infection with phytoplasma varied from 5% in B. olivacea to 35% in Xestocephalus sp. The most abundant leafhopper species, i.e., E. indicus, Y. flavovittatus, and M. hiroglyphicus were used in transmission tests to determine their vector status for the sugarcane white leaf phytoplasma transmission. Infected insects were reared on healthy plants and specific PCR followed by sequencing of the amplicons was used to determine whether the phytoplasma was transmitted to the plants. The results showed that both Y. flavovittatus and M. hiroglyphicus, but not E. indicus, can transmit sugarcane white leaf phytoplasma to healthy sugarcane plants. The transmission efficiency of M. hiroglyphicus (55%) was higher than that of Y. flavovittatus (45%). We conclude that Y. flavovittatus is a newly discovered vector for sugarcane white leaf disease, in addition to M. hiroglyphicus. These two species peak at different times of the year and therefore complement each other in the transmission of the phytoplasma. Because there are no known alternative host plants for the sugarcane white leaf, management of the disease will necessarily require the control of both Y. flavovittatus and M. hiroglyphicus.     

Aspidistra lingyunensis sp. nov. (Asparagaceae) from limestone areas in Guangxi,China

Aspidistra lingyunensis C. R. Lin & L. F. Guo (Asparagaceae) is described and illustrated as a new species from limestone areas in northwestern Guangxi, China. It resembles A. obconica C. R. Lin & Yan Liu in leaf size and its obconical and purplish red pistil, but differs by having a yellowish white perianth, with lobes oblong, explanate, 6–7 mm long, subequal to tube and a white stigma surface, ca 3 mm in diameter. The new species is rare, currently known only from northwestern Guangxi.     

Effects of subsidy quality on reciprocal subsidies: how leaf litter species changes frog biomass export

Spatial subsidies are resources transferred from one ecosystem to another and which can greatly affect recipient systems. Increased subsidy quantity is known to increase these effects, but subsidy quality is likely also important. We examined the effects of leaf litter quality (varying in nutrient and tannin content) in pond mesocosms on gray treefrog (Hyla versicolor) biomass export, as well as water quality and ecosystem processes. We used litter from three different tree species native to Missouri [white oak (Quercus alba), northern red oak (Quercus rubra), and sugar maple (Acer saccharum)], one non-native tree [white pine (Pinus strobus)], and a common aquatic grass [prairie cordgrass (Spartina pectinata)]. We found that leaf litter species affected almost every variable we measured. Gray treefrog biomass export was greatest in mesocosms with grass litter and lowest with white oak litter. Differences in biomass export were affected by high tannin concentrations (or possibly the correlated variable, dissolved oxygen) via their effects on survival, and by primary production, which altered mean body mass. Effects of litter species could often be traced back to the characteristics of the litter itself: leaf nitrogen, phosphorus, and tannin content, which highlights the importance of plant functional traits in affecting aquatic ecosystems. This work and others stress that changes in forest species composition could greatly influence aquatic systems and aquatic–terrestrial linkages.     

Salvia tonaticensis (Lamiaceae), a rare new species from Mexico

Salvia tonaticensis is described and illustrated as a new species to science. It is known from the extreme southern portion of the Estado de Mexico and northern Guerrero, Mexico. It belongs to section Polystachyae; however, unlike the species of the section hitherto known, it possesses simple, bifurcate and trifurcate multicellular hairs on the stems, abaxial leaf surface, petioles, and inflorescence rachis. The flowers are also larger than those of other species of the section, and the calyces are densely tomentose with purple or white multicellular hairs that vary from simple to dendriform. Within the section this species shows some morphological similarities to S. connivens.     

The consequences of delayed greening during leaf development for light absorption and light use efficiency

Many species of rainforest plants have an unusual form of leaf development such that leaves delay greening until after full leaf expansion. Chlorophyll accumulation was measured during leaf development in five woody rainforest species, three with white young leaves, and two with ‘normal’ greening. In the three species with white leaves, the chlorophyll content of the expanding leaves was about 0.4mg dm^?2, whereas in the two species with green young leaves, chlorophyll content was about 2.1 mg dm^?2. Chlorophyll accumulation in greenhouse and field experiments was independent of light level. During leaf expansion, species with delayed chloroplast development only absorb 18–25% of the maximum possible light, compared with 80% for species with normal greening. Furthermore, species with delayed greening have low chlorophyll contents and reduced absorption for at least 30 d after full expansion. At a PPFD typical of the forest under story, the photosynthetic light use efficiency based upon incident radiation was 0.030–0.036 for species with delayed chloroplast development and 0.068–0.085 for the two species with normal greening. The lower light use efficiency of white species was primarily due to decreased light absorption. However, they also had a slightly lower light use efficiency based upon absorbed radiation, suggesting that development of other components of the photo-synthetic apparatus also may be delayed. Despite the fact that delayed greening decreases light absorption and light use efficiency during leaf development, it is extremely common in shade-tolerant species. We suggest that an advantage of delayed greening is that resources are not invested in the leaf until it is fully expanded and better defended from herbivores.     

Gaultheria marronina sp. nov. (Ericaceae) from Sichuan,China

Gaultheria marronina, a new species from the Hengduan Mountain chain of western Sichuan Province, China, is described and illustrated. This species is similar to G. bryoides P. W. Fritsch & L. H. Zhou from the Gaoligong Mountains in its white fleshy calyx with a maroon capsule but differs in its stem setae 0.34–0.50 mm long, petioles 0.4–0.6 mm long, leaf blades 5.1–6.2 × 2.1–3.1 mm, overwintering flower bud pedicels 0.6–0.8 mm long, calyx lobes 2.2–3.0 mm long, and usually slightly open fruiting calyx, among other characters. The species is known only from two widely separated unprotected populations and is categorized as endangered.     

台山含笑，广东木兰科一新种

报道了木兰科（Magnoliaceae）含笑属（Michelia L.）一新种：台山含笑（M. taishanensis Y. H. Tong,X. E. Ye,X. H. Ye & Yu Q. Chen）。该新种目前仅分布于我国广东台山市的北峰山,与广东含笑（M. guangdongensis Y. H. Yan,Q. W. Zeng & F. W. Xing）近缘,但其叶柄更纤细,叶背老时变无毛,雄蕊较多且较长,花丝白色,药隔短小而与后者区别。     

Geometric morphometrics and leaf phenotypic plasticity: assessing fluctuating asymmetry and allometry in European white oaks (Quercus)

Because plants are unable to move away from unfavourable habitats and environmental perturbations, leaf phenotypic plasticity facilitates light absorption and gas exchange. Oaks (Quercus spp.) are particularly known for their adaptability and plastic phenotypes, and leaf allometry and developmental instability may represent important mechanisms for their adaptation to environments and evolution. Because of its important role in the adaptation of plant populations to different environments, allometry can be involved in diversifying selection. Developmental instability is related to environmental perturbations and stresses by producing random deviations in structures characterized by bilateral symmetry, such as oak leaves. In addition, developmental instability can also arise from genetic bottlenecks or as a result of hybridization. The splitting of symmetric and asymmetric components of variation and their separate analysis allows the variability in leaf shape traits to be summarized, reducing the variation produced by developmental instability. The geometric morphometric approach is a useful method for the study of leaf asymmetry and allometric patterns. This method provides an important tool for the visualization of shape attributes that characterize species with highly variable leaf phenotypic patterns. In this study, leaf shape and size variability of three white oak species was investigated by means of a two‐dimensional landmark‐based method providing improved knowledge of variance partitioning, species discrimination, fluctuating asymmetry and allometric patterns of variation resulting from the different analyses. © 2015 The Linnean Society of London, Botanical Journal of the Linnean Society, 2015, 179 , 335–348.     

Autumnal changes in total nitrogen, salt-extractable proteins and amino acids in leaves and adjacent bark of black alder, eastern cottonwood and white basswood

Autumnal changes in total nitrogen, salt-extractable protein and amino acid concentrations in leaves and adjacent bark of black alder [ Ainus glutinosa (L.) Gaertn.], eastern cottonwood ( Populus deltoides Bartr. ex Marsh.) and white basswood ( Tilia heterophylla Vent.) were determined for trees growing on minespoils and a prairiederived loamy soil in central Illinois. The composition of free amino acids in foliage was also determined at peak concentration for each tree species during late senescence. Total nitrogen concentration in the leaves decreased slowly throughout most of the fall for all species. In the final stages of senescence, total leaf nitrogen concentrations were about halved in eastern cottonwood and white basswood but continued to decrease slowly in black alder. The concentration of salt-extractable proteins in leaves of all species peaked early in the fall and then declined prior to leaf abscission. This decline coincided with an increase in the concentration of free amino acids in the leaves. The increase stabilized in both eastern poplar and white basswood but continued in black alder. Glutamine in black alder and eastern cottonwood, and asparagine in white basswood were the most abundant free amino acids at the time of peak concentration of total free amino acids in senescent leaves. Bark of trees of all species had higher nitrogen concentrations and higher proportions of salt-extractable proteins to estimated total proteins after leaf senescence than during the preceding summer. Results indicate that autumnal fluxes in leaf and bark nitrogen fractions of alder can differ substantially from fluxes in other broadleaved winter-deciduous trees in a way which suggests that alder does not effectively conserve leaf nitrogen through retranslocation to bark tissue.     

Aspidistra longgangensis sp. nov. (Asparagaceae) from limestone areas in Guangxi,China

Aspidistra longgangensis C. R. Lin, Y. S. Huang & Yan Liu, a new species of Asparagaceae from the limestone areas in Guangxi, China, is described and illustrated. It is similar to A. guangxiensis S. C. Tang & Yan Liu in the shape of the flower, but differs by leaf blade pachyphyllous and bigger; the perianth lobes with appendages at base, appendage oblong, 3–5 mm long, apex incurved; stigma upper surface white, with 4(3) radial, bifurcate lines in the center. The new species is currently known only from Longgang National Natural Reserve, situated in southwestern Guangxi, China, near the border with northern Vietnam.     

关于白头叶猴分类地位的探讨

通过一只雄性白头叶猴与一只雌性黑叶猴杂交繁殖的F1代(雌体)与黑叶猴(雄体)的回交,成功繁殖出两只回交代个体,出生后两回交代个体健康状况良好,所显露出来的形态学特征介于亲本之间,没有呈现明显的分化现象。杂交代的成功繁殖表明白头叶猴与黑叶猴不存在生殖隔离。从而断定白头叶猴不是一个独立种,而是黑叶猴的一个亚种。     

中国姜黄属一新种—南昆山莪术

报道姜科姜黄属一新种一南昆山莪术（Curcumana nkunshanensis N．Liu,X．B．Ye＆J．Chen）。该种与近缘种广西莪术（C.kwangsiensis X．X．Chen）的区别在于侧根茎分枝多,叶片阔椭圆状披针形,表面光滑无毛,不育苞片下部白色顶端深紫红色,能育苞片绿色。它与郁金（caromatica Safib）的区别在于根茎内面白色,不育苞片下部白色顶端深紫红色,具有种子。     

A comparison of phosphorus and DOC leachates from different types of leaf litter in an urban environment

1. The leaching rates of filterable reactive phosphorus (FRP) and dissolved organic carbon (DOC) from five leaf litter types commonly occurring in urban environments in Mediterranean regions of Southern Australia were compared. The relative composition, bioavailability and oxygen demand of this DOC were also assessed. Four tree species were assessed, including the native river red gum (Eucalyptus camaldulensis) and three introduced deciduous species, the English elm (Ulmus procera), London plane (Platanus acerifolia) and white poplar (Populus alba). Grass cuttings (mixed species) were selected as a common garden waste. 2. Except for English elm, the majority of FRP and DOC was released within the first 48 h. Grass cuttings released the highest amount of FRP with white poplar releasing the most DOC. Species that released relatively high amounts of DOC (white poplar, English elm, river red gum) released relatively low amounts of FRP. Conversely, species that released relatively low amounts of DOC (grass cuttings and London plane) tended to release relatively high amounts of FRP. 3. Analysis of DOC composition, combined with the differing oxygen demand and DOC depletion curves, demonstrated that there were substantial differences in the DOC leached from the leaf litter of the different species. Biochemical oxygen demand and the biodegradability of the DOC was positively correlated with the proportion of hydrophilic and hydrophobic acids present in the leachate. 4. These results demonstrate that simple measurements of nutrient release per gram of leaf litter would be insufficient to predict the ecological impact on receiving waters resulting from changes in dominant vegetation. Furthermore, the use of traps to prevent particulate leaf material from entering streams may have limited potential for reducing the load of dissolved nutrients. We conclude that any changes to vegetation type which substantially alter the timing of leaf fall or the composition of leaf leachates should be avoided.     

中国姜黄属-新种-南昆山莪术

报道姜科姜黄属-新种-南昆山莪术(Curcuma nankunshanensis N.Liu,X.B.Ye&J.Chen).该种与近缘种广西莪术(C kwangsiensis X.X.Chen)的区别在于侧根茎分枝多,叶片阔椭圆状披针形,表面光滑无毛,不育苞片下部白色顶端深紫红色,能育苞片绿色.它与郁金(C aromatica Sahib)的区别在于根茎内面白色,不育苞片下部白色顶端深紫红色,具有种子.     

Roscoea cangshanensis M. H. Luo,X. F. Gao & H. H. Lin,a new species of the Zingiberaceae from Yunnan,China

Roscoea cangshanensis M. H. Luo, X. F. Gao & H. H. Lin, a new species of the Zingiberaceae from Yunnan, China, is described and illustrated. The new species is related to R. forrestii Cowley in habit, but differs in having 2-lobed labellum, each lobe 2-lobulate, base narrowed to a stalk with white lines, and narrower leaf blade, (2–)7–24×1.5–2.5 cm, with base narrow to petiole-like. The new species is also similar to R. debilis Gagnep. in having leaf base narrow to petiole-like, labellum obovate-cuneate, 2.5–3.5×2.5–3.0 cm, with white lines at throat, but differs in having bracts non-tubular, shorter, 5–15 mm long, concealed in leaf sheaths, corolla tubes longer, 10–12.5 cm long, labellum 2-lobed with each lobe further 2-lobulate.     

Hydraulic properties and freezing-induced cavitation in sympatric evergreen and deciduous oaks with contrasting habitats

We investigated the hydraulic properties in relation to soil moisture, leaf habit, and phylogenetic lineage of 17 species of oaks (Quercus) that occur sympatrically in northern central Florida (USA). Leaf area per shoot increased and Huber values (ratio of sapwood area to leaf area) decreased with increasing soil moisture of species’ habitats. As a result, maximum hydraulic conductance and maximum transpiration were positively correlated with mean soil moisture when calculated on a sapwood area basis, but not when calculated on a leaf area basis. This reveals the important role that changes in allometry among closely related species can play in co‐ordinating water transport capacity with soil water availability. There were significant differences in specific conductivity between species, but these differences were not explained by leaf habit or by evolutionary lineage. However, white oaks had significantly smaller average vessel diameters than red oaks or live oaks. Due to their lower Huber values, maximum leaf specific conductivity (K_L) was higher in evergreen species than in deciduous species and higher in live oaks than in red oaks or white oaks. There were large differences between species and between evolutionary lineages in freeze–thaw‐induced embolism. Deciduous species, on average, showed greater vulnerability to freezing than evergreen species. This result is strongly influenced by evolutionary lineage. Specifically, white oaks, which are all deciduous, had significantly higher vulnerability to freezing than live oaks (all evergreen) and red oaks, which include both evergreen and deciduous species. These results highlight the importance of taking evolutionary lineage into account in comparative physiological studies.     

Leaf miners: The hidden herbivores

Leaf mining is a form of endophagous herbivory in which insect larvae live and feed within leaf tissue. In this review we discuss aspects of leaf miner ecology, and the current evidence for three hypotheses relating to the evolution of this feeding guild. We also present a summary of the literature coverage relating to these herbivores, which have been relatively poorly studied compared with insects that feed externally such as sap suckers and leaf chewers. The majority of published studies concern leaf miners from the northern hemisphere, with a general focus on those species considered to be agricultural, forestry or horticultural pests. In a more detailed case study, we examine aspects of leaf miner ecology of Australian species. At least 114 species have been recorded as leaf miners in Australia in four orders: Coleoptera, Lepidoptera, Diptera and Hymenoptera. Lepidoptera and Diptera are the most speciose orders of Australian leaf miners; Hymenoptera are represented by a single endemic genus and half of all coleopteran miners are species introduced for biological control. Both the known number of leaf‐mining species in Australia and the known number of hosts have increased in recent years following new targeted surveys. Leaf miners in Australia occur in many habitats and feed on a wide variety of host plants in at least 60 families although most individual species are monophagous. Although much of the research on leaf miners in Australia has focused on species that are commercially important pests or biological control agents, studies on fundamental aspects of leaf miner ecology are increasing. We identify a number of research questions aimed at better understanding the ecology of leaf miners in Australia and elsewhere.     

中国广西唇柱苣苔属(苦苣苔科)一新种——黄花牛耳朵

报道了在广西发现的苦苣苔科唇柱苣苔属Chirita一新种,即黄花牛耳朵C.lutea Yan Liu & Y.G.Wei.黄花牛耳朵的体态和叶形与牛耳朵(C.eburnea)相似,但前者聚伞花序俯垂,花冠黄色,花药与退化雄蕊先端密被白色绵毛.     

Differentiation of phytoplasmas associated with sugarcane and gramineous weed white leaf disease and sugarcane grassy shoot disease by RFLP and sequencing

 Restriction fragment length polymorphism (RFLP) and sequencing were used to elucidate the genetic relationship between phytoplasmas that cause white lead disease and grassy shoot disease in sugarcane and white leaf disease in gramineous weeds found in the cane-growing areas (Crowfoot grass, Bermuda grass and Brachiaria grass). A 1.35-kb DNA fragment encoding for the 16s rRNA was amplified by PCR using universal primers and analysed by digestion with nine restriction endonucleases. A DNA fragment containing the 3′ end of the 16s rRNA and the spacer region between the 16s rRNA and the tRNA(Ile) was amplified by PCR and sequenced. Analysis of the RFLP patterns and of the sequence showed that grassy shoot and white leaf diseases in sugarcane are caused by two different phytoplasmas. Sequence analysis of phytoplasma DNA obtained from three species of weeds showing symptoms of white leaf disease failed to detect any organism that is identical to those infecting the sugarcane. Moreover the phytoplasma species that infect the three types of gramineous weeds, although closely related, are nevertheless different Received: 15 April 1997 / Accepted: 18 April 1997