Right-Left Symmetry in Phyllotaxy and Imbrication of Flowers of Hibiscus furcartus L.

The phyllotaxy in Hibiscus furcartus is spiral. It is foundthat there is a general tendency for lateral branches to acquirethe same sense (right-handed or left-handed) of phyllotaxy asthe parent branch. H. furcartus has two kinds of flowers, right-handedflowers with clockwise imbricated petals and left-handed flowerswith anticlockwise imbricated petals. It is found that brancheswith right-handed phyllotaxy yield only left-handed flowersand those with left-handed phyllotaxy yield only right-handedflowers. Hibiscus furcartus L., phyllotaxy, imbrication of flowers     

Hemispheric difference in human skin color

Previous studies of human skin color have shown a strong relationship between skin color and distance from the equator, which has been interpreted as a link between skin color, latitude, and the intensity of ultraviolet radiation. The underlying assumptions are that UV radiation is greatest at the equator and that it diminishes with increasing latitude to the same extent in both the Northern and Southern Hemispheres. The standard analysis of human skin color is based on these assumptions, such that skin color is assumed to be darkest at the equator, and the decrease of skin color with latitude is assumed to be the same in both hemispheres. A nonlinear piecewise regression model was developed to test these assumptions and applied to mean skin reflectance data from 102 male samples and 65 female samples from across the Old World. For both males and females, skin reflectance (%) is lowest at the equator (darkest skin). Among males, skin reflectance increases roughly 8.2% for every 10 degrees of latitude in the Northern Hemisphere but only 3.3% for every 10 degrees of latitude in the Southern Hemisphere. Among females, the corresponding numbers are 8.1% in the Northern Hemisphere and 4.7% in the Southern Hemisphere. These results indicate that human skin color is darker in the Southern Hemisphere than in the Northern Hemisphere at equivalent latitude. Recent research shows that UV radiation is higher in the Southern Hemisphere than in the Northern Hemisphere at similar latitude. This difference, relating to astronomical and climatic conditions, may have existed in the past at different times and perhaps influenced the evolution of human skin color. Am J Phys Anthropol 104:449–457, 1997. © 1997 Wiley-Liss, Inc.     

Abnormal Stomatal Opening in Coconut Palms Affected with Root (Wilt) Disease

Studies on the stomatal regulation in the root (wilt) affectedcoconut palms (Cocos nucifera L.) revealed that the diseasedpalms had low stomatal resistance compared to the healthy palms,irrespective of their age. The same trend was observed whetherthe determinations were made at different times of the day (6–18h) or under irrigated and unirrigated conditions or in differentseasons (‘dry’ and ‘wet’). Thus, thestomatal regulation was significantly impaired in the diseasedpalms resulting in excessive water loss compared to the healthypalms. Results are discussed with the available literature onother similar disease caused by fungi, bacteria and mycoplasma-likeorganisms in different plants. Key words: Cocos nucifera L., Stomatal resistance, Root (wilt) disease     

Perspectives in Southern Hemisphere limnology: Introduction

The objectives and rationale of the First International Symposium on Southern Hemisphere Limnology are outlined. The geography and climate of the Northern and Southern Hemispheres are compared. Greater areas of the land masses in the Southern Hemisphere fall under oceanic influence than in the Northern Hemisphere at equivalent latitude. Although many Southern Hemisphere land masses are arid it is concluded that limnological differences between the Hemispheres are of degree rather than of kind and that limnological principles developed in the Northern Hemisphere are, in general, globally applicable. However, Southern Hemisphere water resources management problems have centred upon arid-land water supply problems, probably to the detriment of pure limnological research.     

Thermal characteristics of running waters

This chapter reviews available data on thermal conditions prevailing in lotic ecosystems of the Southern Hemisphere. The primary factors (hydrology, climate, insolation) that interact to determine the thermal régime are examined in the context of southern waters. Maximum temperatures are plotted against annual ranges for equatorial (0–10° latitude), tropical (10–231/2° latitude), and temperate sites. In regions with seasonal climates, running waters exhibit diel and annual thermal periodicity patterns, the phasing of which varies between and within lotic systems. The universality of Illies' river zonation system is analyzed in the context of thermal conditions in Southern Hemisphere running waters.From the relatively limited data base, it appears that Southern Hemisphere running waters exhibit some distinctive features when viewedin toto, compared with Europe and North America where thermal characteristics of lotic habitats have been reasonably well documented. Such differences relate to the generally warm and dry conditions, and to the highly variable and unpredictable climatic régimes characterizing large areas of the Southern Hemisphere. It is concluded that differences in thermal conditions of running waters between hemispheres are a matter of degree rather than of kind, and partly reflect a small woodland stream bias inherent in Northern Hemisphere stream ecology.     

Effects of Organic Nutrients and Hormones on Growth and Development of Tissue Explants from Coconut (Cocos nucifera) and Date (Phoenix dactylifera) Palms Cultured in vitro

The growth response (increase in weight) of cultured explants from seedling date (Phoenix dactylifera L.) and mature coconut (Cocos nucifera L. cv. Malayan Dwarf) palms to source and concentration of organic nitrogen. carbohydrate, auxins, cytokinins and gibberellins was examined. Growth was strongly stimulated by the presence of auxins (10^?7 to 10^?6M), cytokinins (10^?6 to 10^?5M), high concentrations of sucrose (0.2 M), and in the absence of NH₄Cl, by organic sources of reduced nitrogen. Higher concentrations of auxin (2,4-D or NAA at 10^?6 to 10^?5M) which still stimulated growth of Phoenix tissue, proved inhibitory to growth of freshly excised Cocos tissues. Explants from both palms initiated roots when subcultured on a medium with increased levels of auxin (NAA, 2.5 × 10^?6 to 2.5 × 10^?5M) and reduced levels of cytokinin (6-BAP, 5 × 10^?8M). Isolated roots excised from these explants continued growth and produced new laterals when subcultured on media with GA₃ (5 × 10^?7M) and reduced levels of auxin, cytokinin, and either minerals or sucrose.     

Multiple origins of Southern Hemisphere Anemone (Ranunculaceae) based on plastid and nuclear sequence data

 Using two molecular data sets, the plastid atpB-rbcL intergenic spacer region and the nuclear ribosomal internal transcribed spacer regions (ITS), the taxonomic affinities of two newly available Anemone species from the Southern Hemisphere were tested. From previous work based on morphology and geographic distribution, it was assumed that A. tenuicaulis from New Zealand was most closely related to the Tasmanian A. crassifolia, whereas the affinity of A. antucensis from Chile and Argentina was regarded as uncertain. Analyses of molecular sequence data from these and 18 other species of Anemone s.lat. (with Clematis as outgroup) result in trees largely congruent with past analyses based on morphology and plastid restriction site data. They strongly support A. richardsonii and A. canadensis (with boreal distributions in the Northern Hemisphere) as paraphyletic to a well supported Southern Hemisphere clade consisting of A. antucensis and A. tenuicaulis. This group of four species is part of an otherwise predominantly Northern Hemisphere assemblage (subgenus Anemonidium s.lat., chromosome base number x=7), including A. narcissiflora, A. obtusiloba, A. keiskeana and A. (=Hepatica) americana. All other austral species included in the present sampling, A. crassifolia (Tasmania), A. knowltonia (=Knowltonia capensis), and A. caffra (both South African), form a separate clade, sister to A. (=Pulsatilla) occidentalis and other Northern Hemisphere anemones (subgenus Anemone s.lat., x=8). Possible phytogeographical links of the Southern Hemisphere species are discussed. Received April 23, 2001 Accepted October 4, 2001     

Auxin in the Cambium and its Differentiating Derivatives

Cambium and differentiating xylem and phloem tissues from thetrunks of trees of Acer pseudoplatanus L., Fraxinus excelsiorL., and Populus tremula L. were extracted with ether and testedfor auxin, which was found on chromatograms of the acidic fractionat an Rf corresponding to that of indol-3yl-acetic acid in fivesolvent systems. In addition, small amounts of auxin with ahigher Rf in ammoniacal isopropanol were found in phloem samples.The amounts of auxin were greatest in xylem samples, less inthe cambium, and least in phloem. The differences, which cannotbe explained in terms of differential losses during extractionand purification, suggest that auxin is actually formed in differentiatingxylem tissue. The significance of these results is discussed.     

The latitudinal herbivory hypothesis revisited: To be part is to be whole

As the big data accumulation in ecology picks up pace, we now have the opportunity to test several macroecological hypotheses, such as the latitudinal herbivory hypothesis (LHH) dated from the 1990s. The LHH proposes that plant–herbivore interactions decrease as latitude increases, that is, from lower latitudinal areas (i.e., the equator) to higher latitudinal areas (i.e., the poles). This hypothesis has been challenged in recent years. In this study, we used the greatest volume dataset of leaf herbivory from the study of Zhang et al. (Journal of Ecology, 104, 2016, 1089) to test the LHH at a global scale, based on a quantile regression model. We found that the mean annual temperature, mean annual precipitation, and potential net primary production were heterogeneously correlated with herbivory at different quantiles or variable intervals. Although the Northern Hemisphere (NH) and the global‐scale trends are in accordance with the expected latitudinal variation, the Southern Hemisphere (SH) was found to exhibit inverse trends. The latitude has a negative effect on plant–herbivore interactions in the NH and on a global scale; leaf herbivory decreased more at a given latitude in higher latitudinal areas, which is attributed to harsher survival conditions in these areas. The uniformity of leaf herbivory variability along the climate and latitude gradient in the NH and on a global scale motivates that the loosening of this herbivory variability in the SH is not significant enough to dismiss the prevalence of the LHH, a testable macroecology hypothesis.     

Spiral grain in bristlecone pines (Pinus longaeva) exhibits no correlation with environmental factors

Six hundred and eleven Great Basin bristlecone pines (Pinus longaeva) were surveyed in two separate groves in California’s White Mountains. The presence and direction of spiral grain were recorded for each tree as well as elevation above sea level, horizon angles, latitude and longitude, trunk diameter, whether the tree was dead, and whether the trunk was broken. The proportions of left-handed, right-handed and straight trees were similar in every part of both groves, although the groves lie at different elevations. No significant correlation was found between the direction of spiral grain and any environmental factor. The hypothesis that spiral grain is an adaptation to distribute sap evenly between the roots and the crown in Pinus longaeva is not strongly supported, since spiral grain is not correlated with asymmetric environments and most trees exhibit <90° rotation through the main stem. The data also do not support the idea that spiral grain makes the tree more resistant to breaking in strong winds. Right-handed spiral grain is predicted by this hypothesis, but most bristlecone pines are either left-handed or exhibit no spiral grain. Bristlecone pines are often uprooted from thin soils by strong winds, but rarely are the main stems broken by this mechanism. Spiral grain in Pinus longaeva growing in California’s White Mountains does not appear to be under environmental control.     

Global phylogeography in Sanionia uncinata (Amblystegiaceae: Bryophyta)

Global phylogeographic patterns in Sanionia uncinata are addressed based on information in internal transcribed spacer (ITS) (214 specimens) and the plastid markers trnL‐trnF (221) and rpl16 (217). ITS suggests a monophyletic Sanionia and a paraphyletic S. uncinata; this was neither supported nor rejected by plastid data. Northern or Eastern Eurasia and Alaska appear important in the early evolution of Sanionia and some populations dispersed into the Southern Hemisphere relatively early. Some haplotypes or groups of haplotypes are morphologically and ecologically distinct, biologically meaningful units that correspond with S. orthothecioides, S. symmetrica and S. georgicouncinata s.l. The latter includes two species that are indistinguishable by morphology, S. georgicouncinata s.s. (Southern Hemisphere) and S. nivalis (Northern Hemisphere). Tropical African and South American S. uncinata populations have separate origins and the Southern Hemisphere was colonized at least twice. In the northern circum‐Arctic region, the haplotype composition differs between the North Atlantic and Beringian areas. Eastern Eurasia has a higher S. uncinata haplotype diversity than other Holarctic regions, implying less devastating effects of recurrent glacial periods. For Eastern and Western Eurasia, North America and the Southern Hemisphere, most of the haplotype variation was found within the regions, but 14–18% can be referred to among region variation. Plastid haplotype diversity was lower in the Southern Hemisphere than in the Arctic to subarctic, possibly attributable to founder effects. © 2011 The Linnean Society of London, Botanical Journal of the Linnean Society, 2012, 168 , 19–42.     

The Scaling of Plant Height: A Comparison Among Major Plant Clades and Anatomical Grades

The scaling plant height h (m) with respect to stem diameterd (m) was determined for a total 610 species (mosses, n = 40;pteridophytes, n = 16; dicotyledonous herbs, n = 117; palms,n = 17; gymnosperms, n = 105; dicotyledonous trees, n = 315);axial length or mass vs. d was determined for the pteridophytePsilotum nudum ; and the scaling of critical buckling heighth_crit of gymnosperm and dicotyledonous trees was calculatedbased on the record trunk d and average Young's modulus E anddensity p of 33 wood species. The scaling exponents (based onleast squares and reduced major axis regressions;     

Vegetation analogs and differences in the Northern and Southern Hemispheres: A global comparison

Biogeographic comparisons help to identify similarities, differences, larger contexts, and useful hypotheses. Between the (extra-tropical) Northern and Southern Hemispheres taxonomy differs almost completely, but other useful bases for vegetation comparison include phenophysiognomy, form composition and vegetation architecture, subphysiognomic morphology, environmental limits of plant types, taxonomic richness, and some aspects of function. All major biome types occur in both hemispheres except the boreal forests and analogous montane coniferous forests of the Northern Hemisphere. Some vegetation and plant types appear clearly unique, including Eucalyptus, campo cerrado, and flat-cushions such as Azorella, all of these in the Southern Hemisphere. Different but parallel adaptations to different but analogous conditions include the tall submediterranean forests, temperate rainforests, and continental versus maritime temperate deserts. Climatic limits appear similar in the two hemispheres, but mechanisms for some differences remain unresolved. Per unit land area, the Southern Hemisphere has higher annual net primary productivity than the Northern. Dissimilar analogs continue to suggest hypotheses and research questions.     

不同地理种群银杏大蚕蛾COI基因序列变异与遗传分化

银杏大蚕蛾Caligula japonica是亚洲东部的特有种, 既是一种重要的林业害虫, 也是一种珍贵的野生蚕类资源。为了揭示银杏大蚕蛾地理种群间的内在联系, 测定了我国分布的12个地理种群的线粒体细胞色素氧化酶C亚基I（COI）基因部分序列（GenBank登录号: FJ358506-FJ358517）, 对地理种群间的序列变异和遗传分化进行了分析。结果表明: 银杏大蚕蛾地理种群间的COI序列同源性高达99%~100%, 显示出比较小的遗传差异。序列对准后从供试COI序列中仅鉴定出9个变异位点和6个单元型, 其中3种是共享单元型。系统发育分析结果表明种群间已经按地理位置形成了一定的地理格局, AMOVA分析显示北方组和南方组之间已经具有明显的遗传分化（FST=0.478, P<0.001）。综合分析, 我们认为北方组和南方组之间的遗传分化可能与差异巨大的生态条件有关。研究结果为银杏大蚕蛾的种群遗传学和生态学研究提供了一个基本的分子生物学线索。     

Opportunities and challenges in using weather radar for detecting and monitoring flying animals in the Southern Hemisphere

Operational weather surveillance radars (WSRs) are permanent radars that constantly detect precipitation at regular intervals (approx. every 4–10 min) for the purpose of weather reporting and are often part of a larger network of radars. Ecological studies using WSR to detect flying animals within the airspace have been on the rise since the early 2000s. However, the vast majority of published ecological studies (>300) have occurred in the Northern Hemisphere with only two published studies occurring in the Southern Hemisphere, both on insects. The lag in uptake of the technique in the Southern hemisphere is likely due to limited WSR coverage and the challenges of data acquisition and interpretation. However, we argue that WSRs are numerous enough in the Southern Hemisphere to offer equal opportunity to understand the movement of flying animals there. Here, we explore why that might be and present a road map so that ecological researchers in the Southern Hemisphere may take advantage of this valuable data resource.     

<Emphasis Type="Italic">Arabidopsis</Emphasis> petiole torsions induced by lateral light or externally supplied auxin require microtubule-associated TORTIFOLIA1/SPIRAL2

Although rather inconspicuous, movements are an important adaptive trait of plants. Consequently, light- or gravity-induced movements leading to organ bending have been studied intensively. In the field, however, plant movements often result in organ twisting rather than bending. This study investigates the mechanism of light- or gravity-induced twisting movements, coined “helical tropisms.” Because certain Arabidopsis cell expansion mutants show organ twisting under standard growth conditions, we here investigated how the right-handed helical growth mutant tortifolia1/spiral2 (tor1) responds when stimulated to perform helical tropisms. When leaves were illuminated from the left, tor1 was capable of producing left-handed petiole torsions, but these occurred at a reduced rate. When light was applied from right, tor1 plants rotated their petioles much faster than the wild-type. Applying auxin to the lateral-distal side of wild-type petioles produced petiole torsions in which the auxinated flank was consistently turned upwards. This kind of movement was not observed in tor1 mutants when auxinated to produce left-handed movements. Investigating auxin transport in twisting petioles based on the DR5-marker suggested that auxin flow was apical-basal rather than helical. While cortical microtubules of excised wild-type petioles oriented transversely when stimulated with auxin, those of tor1 were largely incapable of reorientation. Together, our results show that tor1 is a tropism mutant and suggest a mechanism in which auxin and microtubules both contribute to helical tropisms.     

Extended gestation with late‐autumn births in a cool‐climate viviparous gecko from southern New Zealand (Reptilia: Naultinus gemmeus)

Abstract Female viviparous lizards from temperate locations in the Southern Hemisphere (New Zealand, Tasmania (Australia), South Africa and South America) often have reproductive activity spanning many months of the year. In contrast, vitellogenesis and pregnancy are often confined to the spring/summer months in viviparous species from temperate zones of the Northern Hemisphere. An extreme Southern Hemisphere example is the nocturnal common gecko from New Zealand, Hoplodactylus maculatus (Gray 1845), in which females exhibit biennial reproduction with pregnancy lasting up to 14 months in a cool‐climate population. Here, we examined whether such an extended reproductive cycle also occurs in a diurnal species, the jewelled gecko Naultinus gemmeus (McCann 1955), at a similar latitude. Palpation was used to assess reproductive condition non‐invasively. In contrast to the nearby higher‐altitude population of H. maculatus, N. gemmeus reproduces annually. Vitellogenesis occurs from autumn to spring in both species, but pregnancy ends after about 7 months in N. gemmeus. Birth occurs in the seemingly unpropitious season of mid‐ to late autumn, a pattern that may be unique for lizards from cool‐temperate zones. We hypothesize that there are major differences between populations of N. gemmeus and H. maculatus with respect to survival of autumn‐born neonates and/or costs to females from remaining pregnant over winter. Museum specimens of N. gemmeus support anatomical inferences from palpation; they also suggest that vitellogenesis may begin before the end of pregnancy (which may be essential to completing each reproductive cycle within a year) and that some populations may show gestation in utero over winter, as in H. maculatus. Extended gestation appears to be a common response to cool climates for Southern Hemisphere lizards that have independently evolved viviparity.     

Termite Prey Specialization in the Pitcher Plant Nepenthes albomarginata--Evidence from Stable Isotope Analysis

Old World pitcher plants (Nepenthes spp., Nepenthaceae) trapand digest invertebrate prey to derive nutrients, primarilynitrogen (N). In the majority of lowland Nepenthes species studiedto date, ants (Hymenoptera, Formicidae) are numerically thedominant prey taxon. Nepenthes albomarginata is unusual in showingan apparent bias towards the capture of termites (Isoptera).We tested the hypothesis that N. albomarginata derives N fromtermite capture, by comparison of foliar stable N isotope abundance(     

Genetic Analysis of the Effects of Polar Auxin Transport Inhibitors on Root Growth in Arabidopsis thaliana

Polar auxin transport inhibitors, including N-1-naphthylphthalamicacid (NPA) and 2,3,5-triiodobenzoic acid (TIBA), have variouseffects on physiological and developmental events, such as theelongation and tropism of roots and stems, in higher plants.We isolated NPA-resistant mutants of Arabidopsis thaliana, withmutations designated pir1 and pir2, that were also resistantto TIBA. The mutations specifically affected the root-elongationprocess, and they were shown ultimately to be allelic to aux1and ein2, respectively, which are known as mutations that affectresponses to phytohormones. The mechanism of action of auxintransport inhibitors was investigated with these mutants, inrelation to the effects of ethylene, auxin, and the polar transportof auxin. With respect to the inhibition of root elongationin A. thaliana, we demonstrated that (1) the background levelof ethylene intensifies the effects of auxin transport inhibitors,(2) auxin transport inhibitors might act also via an inhibitorypathway that does not involve ethylene, auxin, or the polartransport of auxin, (3) the hypothesis that the inhibitory effectof NPA on root elongation is due to high-level accumulationof auxin as a result of blockage of auxin transport is not applicableto A. thaliana, and (4) in contrast to NPA, TIBA itself hasa weak auxin-like inhibitory effect. (Received April 12, 1996; Accepted September 2, 1996)