Leaf cuticular wax amount and crystal morphology regulate post-harvest water loss in mulberry (Morus species)

Mulberry leaves are the sole source of food for silkworms (Bombyx mori), and moisture content of the detached leaves fed to silkworms determines silkworm growth and cocoon yield. Since leaf dehydration in commercial sericulture is a serious problem, development of new methods that minimize post-harvest water loss are greatly needed. In the present study, variability in moisture retention capacity (MRC, measured as leaf relative water content after one to 5 h of air-drying) was examined by screening 290 diverse mulberry accessions and the relationship between MRC and leaf surface (cuticular) wax amount was determined. Leaf MRC varied significantly among accessions, and was found to correlate strongly with leaf wax amount. Scanning electron microscopic analysis indicated that leaves having crystalline surface waxes of increased facet size and density were associated with high MRC accessions. Leaf MRC at 5 h after harvest was not related to other parameters such as specific leaf weight, and stomatal frequency and index. This study suggests that mulberry accessions having elevated leaf surface wax amount and crystal size and density exhibit reduced leaf post-harvest water loss, and could provide the foundation for selective breeding of improved cultivars.     

New Sphenophyllum plant from the Upper Devonian of Zhejiang Province,China

Sphenophyllum was an important and long-surviving sphenopsid genus in the Paleozoic floras, with a worldwide distribution. A new species, Sphenophyllum changxingense sp. nov., is described from the Upper Devonian Wutong Formation of Changxing County, Zhejiang Province, China. This plant is characterized by two orders of slender axes and wedge-shaped leaves borne in whorls. The axes bear short spines and show longitudinal ridges and furrows on surface. Three to eight isophyllous leaves, with one, two, or no second-order axes, are attached at each node of first-order axes. Leaves bear spines and show a bilobate morphology; the two leaf lobes divide distally to form several marginal segments, each segment with a leaf vein. Sphenophyllum changxingense represents an early and primitive species within the genus, in light of the absence of heterophylly and specialized hook-like leaves. Like some Carboniferous and Permian species, it appears to have formed dense mats with mutually supportive axes. This plant adds to the known diversity of early sphenopsids in the Late Devonian.     

中国野生山梨叶片形态及光合特性

以异位保存在国家梨资源圃的48份我国原产山梨品种和2份秋子梨地方品种为材料,比较了野生山梨与地方秋子梨品种间差异,研究了我国野生山梨的光合特征以及光合特性相关指标间的关系,建立了山梨光合及瞬时水分利用特征的线性回归方程.结果表明:地方品种叶片形态特征指标、叶绿素含量、光合特征指标都显著低于野生品种平均值,且低于大部分野生品种的测定值;山梨叶片的比叶面积、叶干物质含量、胞间CO2浓度的变异系数较低,其他8项指标变异系数为0.12～0.41,表现出较高的多样性水平,可见我国野生山梨资源光合特征差异明显;光合特性指标与叶绿素组成(Chl a/b)、叶干物质含量呈显著相关;光合速率与胞间CO2浓度、蒸腾速率、气孔导度呈显著的指数曲线关系,山梨光合速率主要受气孔限制的影响.‘锦州山梨’具有高光合特性,可作为山梨资源光合特征研究利用的良好材料.     

中国花椒属（广义）叶表皮特征初步研究

利用光镜和扫描电镜对国产花椒属Zanthoxylum s.1.40种(变种)植物的叶表皮形态特征进行了观察.结果发现:无规则型气孔器普遍存在于所有研究种类叶下表皮及个别种类叶上表皮;叶表皮细胞有规则多边形、不规则多边形2种形态;垂周壁式样有平直、浅波状和深波状3种类型.在扫描电镜下,叶表皮气孔器外拱盖内缘为平滑、浅波状或波状;气孔器附近的角质膜平坦或皱褶.表面光滑或具有各种纹饰.叶表皮形态特征研究结果表明崖椒亚属subgen.Fagara与花椒亚属subgen. Zanthoxylum之间存在有许多的共同点,它们共同组成广义花椒属.文中还对叶表皮特征在花椒属部分种类分类中的应用进行了讨论.     

中国杜鹃花属的叶表皮特征及其系统学意义

通过光学显微镜和扫描电镜对国产杜鹃花属Rhododendron6个亚属48种4变种植物的叶表皮特征进行观察,结果表明叶表皮的鳞片、腺体、表皮毛的有无和气孔器的类型具有一定的系统学意义。光学显微镜下可见：叶表皮细胞形状为多边形、不规则形,垂周壁式样为较平直、浅波状和波状．气孔器普遍存在于下表皮,上表皮未见气孔器分布,其类型均为无规则形。杜鹃亚属subgen．Rhododendron叶表皮具有鳞片,在扫描电镜下可见气孔器散生于指状突起之间,有别于无鳞类杜鹃花。常绿杜鹃亚属subgen．Hymenanthes和映山红亚属subgen．Tsutsusi有多种不同叶表皮类型;除了凯里杜鹃R．westlandii和弯蒴杜鹃R．henryi形态较特殊之外,马银花亚属subgen．Azaleastrum的马银花组sect．Azaleastrum和长蕊杜鹃组sect．Choniastrum微形态区别不明显。羊踯躅亚属subgen．Pentanthera的羊踯躅R．molle叶表皮有表皮毛,无腺体,气孔器密生,外拱盖形状不对称,外围有多层波形条纹突起可与其他亚属区分：而叶状苞亚属subgen．Therorhodion的叶状苞杜鹃R．redowskianum保卫细胞有明显的T型加厚,与其他亚属种类明显不同,与分子系统发育研究得到的“叶状苞亚属是杜鹃花属的基部类群”的结果吻合。本研究还依据叶表皮微形态特征讨论了一些近缘种类的关系。     

Functional morphology of the cuticular terraces in burrowing terrestrial brachyuran decapods

Observations on Gecarcinus lateralis and Ocypode quadrata from Bermuda show that their cuticular terraces are not functional as burrowing sculptures, as previously assumed. Instead, they increase the friction against the walls of the burrow when the animal wedges itself to avoid being extracted by predators. No significant increase in the number of terraces takes place during growth in the size interval available for this study. This is different from the situation described as usual in burrowing decapods, and is rather similar to that of crevice-dwelling crabs. The distribution of terraces and their ontogenetic pattern, therefore, are not reliable indicators of the life habits.     

Cancrinella and Costatumulus (Brachiopoda) from the Permian of South Mongolia and South China: Their morphology,biostratigraphy and distribution

Two brachiopod genera, Cancrinella Fredericks and Costatumulus Waterhouse, are studied from the Permian of South Mongolia and South China. Many of the specimens previously described as Cancrinella are revised and assigned to Costatumulus. The new data presented in this paper indicate that these two genera are similar to each other, but are distinguishable by different features in relation to their morphology. Several species of both genera are described here, providing critical new information on the morphology and taxonomy of Cancrinella and Costatumulus. The reported biostratigraphical information reveals that species of Cancrinella are present from the Lower Carboniferous (Tournaisian) to Middle Permian (Capitanian), whereas species of Costatumulus are mostly restricted to the Lower Permian (Sakmarian) to Upper Permian (Changhsingian). An analysis of the palaeogeographical distribution of Cancrinella and Costatumulus reveals that Cancrinella was more commonly distributed in the Northern Transitional Zone and the Boreal Realm, in contrast to Costatumulus, which tended to be more common in the Southern Transitional Zone and Gondwanan Realm.     

Phylogenetic diversity and ecological features in the Egyptian flora

Until fairly recently, regional-scale ecological and evolutionarypatterns have tended to be ignored as conservation efforts have been concernedwith species and their habitats. Here we compare frequencies in the Egyptianflora of particular rank sizes (order, family and genus) with patterns ofspecies abundance (classified as very rare, rare, common, or very common) and anarray of life-history attributes. The angiosperm flora of Egypt is representedby 2446 taxa (2088 species), including taxa in 10 subclasses, 51 orders, 120families, and 742 genera. A high degree of monotypism was observed: four ordersare monotypic (each existing as single species), and have very rare overallabundances; 30 families are monotypic (17 of which are very rare or rare); and 354genera are monotypic (over 70% of which are very rare or rare). Fourteenfamilies (in particular the Resedaceae and Zygophyllaceae) have at leastone-fifth of their global species represented in the Egyptian flora. Introducedspecies in general, and tree, aquatic herb and liana life forms all are especially well represented among monotypic genera. Native taxa are highlyrepresented among rare and very rare abundance classes, while introduced taxadid not differ significantly in their abundance patterns, compared to overallflora values. Few large genera (>20 spp.) occur in the flora, with mostspecies concentrated in genera containing 8–19 species per genus.Similarly, few families were highly speciose. Annual and herbaceous species weresignificantly over-represented, mainly among large, speciose genera andfamilies. However, perennials, trees, shrubs, aquatic herbs, lianas and parasiticspecies were found mainly in families and genera having very few taxa.Life-history attributes may have important implications to speciation rates.Taxonomically based results, involving abundances and life-history attributes,are discussed in the context of biodiversity and conservation.     

Two new combinations in the South Sudanese flora

Two new combinations are made in preparation for a forthcoming checklist of the plants of Sudan and South Sudan: Dicliptera lanceolata (Lindau) I. Darbysh. & Kordofani (Acanthaceae), a South Sudan endemic, and Campylospermum likimiense (De Wild.) I. Darbysh. & Kordofani (Ochnaceae), recorded from South Sudan and Ethiopia to Tanzania and the Democratic Republic of Congo. Lectotypes are designated for each name. The habitat and ecology, distribution within South Sudan and conservation status are presented for each species.     

Leaf cuticular waxes are arranged in chemically and mechanically distinct layers: evidence from Prunus laurocerasus L.

The composition and spatial arrangement of cuticular waxes on the leaves of Prunus laurocerasus were investigated. In the wax mixture, the triterpenoids ursolic acid and oleanolic acid as well as alkanes, fatty acids, aldehydes, primary alcohols and alcohol acetates were identified. The surface extraction of upper and lower leaf surfaces yielded 280 mg m ^{? 2} and 830 mg m ^{? 2}, respectively. Protocols for the mechanical removal of waxes from the outermost layers of the cuticle were devised and evaluated. With the most selective of these methods, 130 mg m ^{? 2} of cuticular waxes could be removed from the adaxial surface before a sharp, physically resistant boundary was reached. Compounds thus obtained are interpreted as ‘epicuticular waxes’ with respect to their localization in a distinct layer on the surface of the cutin matrix. The epicuticular wax film can be transferred onto glass and visualized by scanning electron microscopy. Prunus laurocerasus epicuticular waxes consisted entirely of aliphatic compounds, whereas the remaining intracuticular waxes comprised 63% of triterpenoids. The ecological relevance of this layered structure for recognition by phytotrophic fungi and herbivorous insects that probe the surface composition for sign stimuli is discussed.     

Leaf sheath cuticular waxes on bloomless and sparse-bloom mutants of Sorghum bicolor

Leaf sheath cuticular waxes on wild-type Sorghum bicolor were approximately 96% free fatty acids, with the C28 and C30 acids being 77 and 20% of these acids, respectively. Twelve mutants with markedly reduced wax load were characterized for chemical composition. In all of the 12 mutants, reduction in the amount of C28 and C30 acids accounted for essentially all of the reduction in total wax load relative to wildtype. The bm2 mutation caused a 99% reduction in total waxes. The bm4, bm5, bm6, bm7 and h10 mutations caused more than 91% reduction in total waxes, whereas the remaining six mutants, bm9, bm11, h7, h11, h12 and h13, caused between 35 and 78% reduction in total wax load. Relative to wild-type, bm4 caused a large increase in the absolute amount of C22, C24 and C26 acids, and reduction in the C28 and longer acids, suggesting that bm4 may suppress elongation of C26, acyl-CoA primarily. The h10 mutation increased the absolute amounts of the longest chain length acids, but reduced shorter acids, suggesting that h10 may suppress termination of acyl-CoA elongation. The bm6, bm9, bm11, h7, h11, h12 and h13 mutations increased the relative amounts, but not absolute amounts, of longer chain acids. Based on chemical composition alone, it is still uncertain which genes and their products were altered by these mutations. Nevertheless, these Sorghum cuticular wax mutants should provide a valuable resource for future studies to elucidate gene involvement in the biosynthesis of cuticular waxes, in particular, the very-long-chain fatty acids.     

Leaf cuticular waxes and physiological parameters in alfalfa leaves as influenced by drought

Drought significantly constrains higher yield of alfalfa (Medicago sativa L.) in arid and semiarid areas all over the world. This study evaluated the responses of leaf cuticular wax constituents to drought treatment and their relations to gas-exchange indexes across six alfalfa cultivars widely grown in China. Water deficit was imposed by withholding water for 12 d during branching stage. Cuticular waxes on alfalfa leaves were dominated by primary alcohols (41.7?C54.2%), alkanes (13.2?C26.9%) and terpenes (17.5?C28.9%), with small amount of aldehydes (1.4?C3.4%) and unknown constituents (4.5?C18.4%). Compared to total wax contents, the wax constituents were more sensitive to drought treatment. Drought decreased the contents of primary alcohol and increased alkanes in all cultivars. Alkane homologs, C25, C27, and C29, were all negatively correlated with photosynthetic rate, transpiration rate, stomatal conductance, and leaf water potential. Under drought conditions, both stomatal and nonstomatal factors were involved in controlling water loss from alfalfa leaves. No direct relationship was observed between wax contents and drought resistance among alfalfa cultivars. An increase in alkane content might be more important in improving drought tolerance of alfalfa under water deficit, which might be used as an index for selecting and breeding drought resistant cultivars of alfalfa.     

Phosphatized rare star-like mouth disc of Punctatus and its functional morphology from the earliest Cambrian of the South Shaanxi China

The Meishucun stage is the prelude in decipher-ing the Cambrian Explosion. In this prominent stage, rapid radioactive evolution and body-plan innovation have taken place and different associations of organism have been shaped. In this paper we report several 3D-preserved rare star-like fossils with finely preserved soft tissues which were recovered from the Kuanchuanpu Member of the Dengying Formation in South Shaanxi, China in 2003. By studying on functional morphology and analogy with mouthpart of Punctatus, there are evidences that this star-like organism approaches the coelenterates in systematic classification and the centre of star-like organism is its mouth. The appearance of coelenterates marks the real beginning of metazoan evolution. Therefore, it has the prominent position in the origin and evolutionary history of organisms. Perhaps the star-like organism represents the early types of coelenterate with original tentacles. These new materials provide new evidence for the origin, evolution and the functional evolution of the metazoan during the early stage of the Cambrian Explosion.     

Composition of soluble cuticular lipids and water permeability of cuticular membranes from Citrus leaves

Water permeability and composition of soluble cuticular lipids of isolated cuticular membranes from leaves of Citrus aurantium L. were investigated for 3 successive years. The average water permeability coefficient determined using 169 cuticular membranes was 1.09·10^–7 cm s^–1 with a standard deviation of 0.78·10^–7 cm s^–1. There were no significant differences in water permeability between years. Cuticular membranes are characterized by a great variability in water permeability both within and between years. Both water permeability of individual membranes and variability between membranes are shown to be determined by soluble cuticular lipids contained within the cuticular membranes. The soluble cuticular lipids of Citrus leaves are composed of fatty acids, primary alcohols, esters, and hydrocarbons. They occur in amounts of 9.84 g cm^–2, which represents approx. 3% of the total mass of isolated cuticular membranes. The specific weight of cuticular membranes (365.4 g cm^–1) and total amount of soluble cuticular lipids did not vary significantly between years. Significant differences were observed for the amounts and composition of the constituent classes of lipids. Six homologues comprise 86% of the fatty acids (C₁₆; C₁₈; C₁₉; C₂₁; C₂₄; C₂₆), 83% of the primary alcohols (C₂₄; C₂₆; C₂₈; C₃₀; C₃₂; C₃₄) and 88% of the esters (C₃₆; C₃₈; C₄₀; C₄₁; C₄₂; C₄₄). Eleven major homologues amount only to 62% of the total hydrocarbons (C₁₆; C₁₇; C₁₈; C₂₀; C₂₆; C₂₇; C₂₉; C₃₀; C₃₁; C₃₂; C₃₃). Variability in the composition of soluble cuticular lipids between years was much smaller than variability of water permeability and, therefore, no relation between composition of soluble cuticular lipids and water permeability could be found. It is suggested that this may be due to the fact that the lipid composition observed represents the averages of 20 to 30 membranes analyzed so that differences between individual membranes may have been leveled out.Abbreviations CM cuticular membranes - MX polymer matrix - P_d permeability coefficient for diffusion of water - SCL soluble cuticular lipids - MES morpholinoethane sulphonic acid     

钦州湾浮游植物周年生态特征

2008-2009年对钦州湾及附近海域进行4个季节航次的浮游植物调查,共鉴定出浮游植物131种,其中硅藻种数最多,达101种,占浮游植物总种数的77.1％;甲藻次之,23种;其他种类3门7种.浮游植物以广温性种和暖水性种为主.总种类数的季节变化与硅藻种类数均为春季最低,夏、秋、冬依次增加,冬季最高.各季节浮游植物丰度为232.28×104～ 977.0×104 cell·m-3,平均为558.57×104 cell·m-3;各季节浮游植物丰度呈现夏、春、冬和秋依次减少的趋势;各区域浮游植物丰度四季均为由内湾至外湾先升高、到湾外逐渐降低的趋势,但在夏季其高丰度区由外湾南移至湾口附近.浮游植物群落的Shannon多样性指数和均匀度指数平均值分别为3.18和0.63,多样性水平较高.浮游植物丰度与温度、盐度、溶解性无机氮及活性磷酸盐的相关关系因季节而变化.     

Taxonomic and ecological implications of leaf cuticular morphology in Castanopsis, Castanea, and Chrysolepis

Leaves of 41 species of Castanopsis, six species of Castanea, and Chrysolepis chrysophyllum Hjelmq. were examined. In Castanopsis, all species possessed cyclocytic stomata with thickened subsidiary cells; thin-walled peltate trichomes are the most frequent type on the abaxial surface of the leaves of this genus. In Castanea, stomata are transitional between cyclocytic and anomocytic; thin-walled peltate trichomes were recorded for the first time on the abaxial surface of Castanea leaves. In Chrysolepis, cyclocytic stomata with non-thickened subsidiary cells and thick-walled peltate trichomes were observed. The thickened subsidiary cells support the placement of the “fissa-group” in Castanopsis. The results of this study support the idea that Castanopsis and Castanea are sister groups. Thick-walled peltate trichomes were only recorded in Chrysolepis, thus supporting its taxonomic separation from Castanopsis. The phylogenetic distribution of trichome types among genera of Fagaceae is summarized. The evolutionary trends of trichome types in Castanopsis are discussed, as are the implications of stomatal and trichome features on fossil identification and ecology.     

Interpreting some outstanding features of the flora and vegetation of Madagascar

Six features are covered. (1) The high endemism, which is not discussed in detail, is all-pervasive, and has resulted from the isolation of Madagascar from Africa some 125 million years ago and their present separation by 430 km. (2) The great richness in plant species (especially relative to Africa), seen particularly in the families of woody species in the wetter vegetation-types, involves both sympatry and allopatry within genera, and is explicable in terms of much less extreme drying out than in Africa during the Pleistocene and effective ‘species-pumping’ rather than mass extinctions during that period. (3) The abundance and species-richness of palms, pandans, tree-ferns, bamboos, and certain families of dicot trees (notably Lauraceae, Monimiaceae, Myrsinaceae and Myristicaceae) in the lowland rain forests also appears to be a result of both past and present wetness of the climate, while it is hypothesized that the low stature of most lowland rain forests, paucity of large-girth trees, and small size and sparsity of broad-leaved herbs, are a result of most rain forest soils being old and relatively nutrient-poor. (4) Within the dry evergreen forest region where rainfall is moderate (900–1600 mm yr⁻¹) a sub-set of trees with fire-resistant bark seems to have evolved at sites prone to frequent ground fires, some perhaps spreading out of adjacent palm savanna on seasonally flooded sites. (5) Both the evolution of thicket rather than grassy woodland in the driest areas (300–600 mm yr⁻¹), and the abundance of evergreen trees and shrubs on ordinary soils – not confined to run-on sites – are explicable in terms of there being a finite chance of rain throughout the year rather than one short wet season, coupled with relatively high values for air humidity throughout the year. The same factors probably explain the abundance and variety of succulents in the thicket; they are found throughout and not just on rocks. (6) Concerning physical defence against herbivores, the rain forests, dry evergreen forests and deciduous forests all show a complete lack of plants with physiognomic features plausibly related to browsing by extinct giant birds (a strong contrast with New Zealand), but in the semi-deciduous thicket there are many tiny-leaved, mostly non-spiny shrubs and small trees, whose dense branching and impenetrability have plausibly evolved as a defence against browsing by elephant birds. The Didiereaceae of the thicket are spiny (unlike members of the same family in Africa), and are giant analogues of the ‘ocotillo’ (Fouquieria splendens) in western North America rather than of Cactaceae; their spines appear to be protecting the leaves more than the stems against arboreal primates, spine length paralleling leaf length.     

Contribution to the orchid flora of South Central Africa

11 new taxa (8 new species, 3 new varieties) ofOrchidaceae are described from South Central Africa, including data on their habitat and distribution and discussions of their systematic affinities.