Intra-individual heterostyly in Atriplex halimus L. (Amaranthaceae)

Classically, the Atriplex halimus L. female flower is perianthless, has two bracteoles, one ovary and one style. Considering bracteoles, one can distinguish, among the representatives of two Tunisian populations, three phenotypes of female flowers, each of them being distributed in three types according to the style length. Male flowers produce three types of pollen. This is the only known example of intra-individual heterostyly in unisexual flowers. These results question the classical concept of individual. The authors discuss a possible process implying indirectly hybridisation and introgression between A. halimus and A. nummularia.     

Phytoextraction of cadmium by four Mediterranean shrub species

The possibility of remediating contaminated soils though the use of high biomass-generating, native plant species capable of removing heavy metals is receiving increased attention. The cadmium (Cd) accumulation capacities of the native Mediterranean, perennial shrubs Atriplex halimus, Phyllirea angustifolia, Rhamnus alaternus and Rosmarinus officinalis were tested by growing transplanted specimens in a pine bark compost substrate (pH 5.6) contaminated with 100 mg Cd kg(-1). After 70 days, only R. alaternus showed reduced growth. The increase in biomass seen in all the test species enhanced the phytoextraction of Cd. However, the species behaved as metal excluders, except for the halophyte A. halimus, which behaved as an indicator plant. In this species the leaf Cd concentration reached 35 mg Cd kg(-1), with the shoot responsible for some 86% of total Cd accumulation. Atriplex halimus showed the highest bioconcentration factor (BCF) (0.36) and leaf Cd transport index (1.68); consequently, this species showed the highest Cd phytoextraction capacity.     

Genetic structure of Atriplex halimus populations in the Mediterranean Basin

BACKGROUND AND AIMS: The saltbush Atriplex halimus is a chenopodiaceous plant well adapted to dry saline habitats and widely distributed in the Mediterranean Basin. A study was carried out to analyse the genetic diversity of A. halimus at the level of the Mediterranean Basin. METHODS: To assess the intra- and interpopulational variation of A. halimus a total of 51 populations and six plants per populations was analysed with the RAPD-PCR technique. For the study of the phylogeny of the populations, 21 samples of A. halimus and seven samples of other species of Atriplex were analysed by the sequencing of the ITS (internal transcribed spacer) region of the ribosomal DNA. KEY RESULTS: The AMOVA analysis of the RAPD results showed that populations were divided into two discrete genetic groups, as the variation among groups accounted for 54.36 % of the total variance of the collection. At the same time, the intrapopulational diversity was high, as 301 out of 306 plants analysed constituted an individual RAPD haplotype. The sequencing of the ITS region also showed a significant separation of the two genetic groups, with a genetic distance of 0.023 nucleotide substitutions per site. Using A. breweri, A. canescens, A. glauca and A. prostrata as outgroups in the phylogenetic analysis, A. breweri and A. canescens are the species closest to A. halimus from this group, while A. prostrata is the most distant. CONCLUSIONS: The present work indicates that two genetic groups of A. halimus can be distinguished after analysing the genetic diversity of 51 populations from ten countries in the Mediterranean Basin.     

RESURRECTION OF THE GENUS ENDOLEPIS AND CLARIFICATION OF ATRIPLEX PHYLLOSTEGIA (CHENOPODIACEAE)

The genus Endolepis was first described by Torrey in 1860 with E. suckleyi (E. dioica [Nutt.] Standley) as the only species, noting that it differed from species of Atriplex by the presence of perianth parts in the female flowers. Later, Standley described two additional species: E. covillei and E. monilifera. H. M. Hall and Clements merged Endolepis with Atriplex because they thought that the presence of perianth parts in female flowers was variable in Atriplex phyllostegia. It is now clear that this observation was erroneous; A. phyllostegia never has perianth parts in its female flowers. The plants that they examined that had female flowers with perianth parts were specimens of Endolepis covillei; only those with female flowers devoid of perianth parts were specimens of Atriplex phyllostegia. These two taxa differ by several other major attributes including differences in leaf shape, leaf anatomy, fruiting-bract size and shape, fruiting-bract appendages, and flowering habit, and therefore justify taxonomic separation. Also, because the presence of perianth parts in bracteolate female flowers is a rare attribute in the tribe Atripliceae, consistently absent in Atriplex, but always present in Endolepis, the retention of the genus Endolepis, separate from Atriplex, is deemed warranted. We propose that the genus Endolepis comprise two species, E. dioica and E. covillei. The species named E. monilifera by Standley is based on a specimen of Atriplex serenana Nels.     

Contributo preliminare alla sistematica di Chamaecytisus hirsutus e Chamaecytisus supinus

Abstract

Chamaecytisus hirsutus and C. supinus: a preliminary report. – Chamaecytisus hirsutus (L.) Link and C. supinus (L.) Link have been described as twostrictly related species, which differ mainly in the form of inflorescence: C. hirsutus has lateral flowers, C. supinus has terminal flowers. Besides, most Floras provide a set of additional differential characters that should permit to di-C. hirsutus and C. supinus.

The author analyses such differential characters and demonstrates that all of them are inconsistent: therefore the inflorescence seems to be the only difference between C. hirsutus and C. supinus.

The inflorescence itself, however, is not a constant character: indeed, it is known that C. supinus may develop vernal latera flowers besides the normal aestival terminal ones.

The geographic distributions of the two inflorescence types are accurately examined (a report of the distributions is given, a list of herbarium specimens is presented in appendix, a point distribution map of the two types is given in figs. 1 and 2); the only differences are the following ones: plants with flowers in leafy racemes (usually identified as C. hirsutus) seem to be absent from Spain and from Southern Poland, and to be unfrequent in Central and Western France; instead, plants with flowers in heads (usually identified as C. supinus) are very unfrequent in the Southern Balcan Peninsula, and are absent from Southern Greece and the Italian Peninsula.

After a discussion of the biological significance of the capitate and lateral inflorescence, and on the basis of in vivo observations, the author argues that probably the same taxonomic unit is present in the whole area, showing some differences in its flowering behaviour; in the largest part of the areal – including the center of distribution of the species – most individuals flower twice, and therefore have been recorded as two different species; a trend toward the capitate inflorescence is remarkable in the North and in the West; instead, in the South and the East the trend is toward lateral flowers (fig. 3).

Further biometrical and biochemical studies on the species are now in progress; more observations in field in different parts of Europe are necessary in order to get conclusive evidence of the identity of these two so-called «species».     

茜草科螺序草属一新种——阳春螺序草(英文稿)

描述了自广东省发现的茜草科一新种——阳春螺序草,其与宽昭螺序草相似,两者均具有半木质化的茎、披针形的叶片、线状的苞片和小苞片以及高脚碟形的花冠,但本种因茎叶无毛、花序蝎尾状、花萼裂片小三角形、长柱花的雄蕊着生位置更近于花冠管基部等特征而不同于后者.目前阳春螺序草仅在其模式种产地发现一个不足200株的居群,根据IUCN评价标准,其应处于濒危(EN)等级.     

Inflorescence architecture affects pollinator behaviour and mating success in Spiranthes sinensis (Orchidaceae)

? Despite the wide inflorescence diversity among angiosperms, the effects of inflorescence architecture (three-dimensional flower arrangement) on pollinator behaviour and mating success have not been sufficiently studied in natural plant populations. ? Here, we investigated how inflorescence architecture affected inter- and intra-plant pollinator movements and consequent mating success in a field population of Spiranthes sinensis var. amoena (S. sinensis). In this species, the flowers are helically arranged around the stem, and the degree of twisting varies greatly among individuals. The large variation in inflorescence architecture in S. sinensis results from variation in a single structural parameter, the helical angle (the angular distance between neighbour-flower directions). ? The numbers of visits per inflorescence and successive probes per visit by leaf-cutting bees decreased with helical angle, indicating that individual flowers of tightly twisted inflorescences received less visitations. As expected from pollinator behaviour, pollinia removal and fruit set of individual flowers decreased with helical angle. Meanwhile, geitonogamy decreased in tightly twisted inflorescences. ? Our novel findings demonstrate that natural variation in inflorescence architecture significantly affects pollinator behaviour and reproductive success, suggesting that inflorescence architecture can evolve under pollinator-mediated natural selection in plant populations. We also discuss how diverse inflorescence architectures may have been maintained in S. sinensis populations.     

Geitonogamy in rewarding and unrewarding inflorescences: modelling pollen transfer on actual foraging sequences

Many orchid species are unusual in that they provide no nectar or pollen rewards for their pollinators. Absence of reward is expected to have a fundamental effect on pollinator visitation patterns. In particular the number of flowers visited per inflorescence is expected to be affected in both unrewarding and co-flowering rewarding species. We used arrays of artificial inflorescences, which could be either rewarding or unrewarding and were differentiated by their colour, to test how many flowers bumblebees visit in each type of inflorescence. The frequency of the two colours was varied, thus modelling the case where different frequencies of both an unrewarding and rewarding species were present in a patch. We found that bumblebees visited more flowers per rewarding inflorescence after they have experienced unrewarding or partially emptied rewarding inflorescences. We used these results to simulate pollen transfer and thus predict selfing rates on rewarding inflorescences. We found these increased when nectar depleted or when there was a greater proportion of unrewarding inflorescences in the patch. Conversely, we found that the number of flowers bumblebees visited on each unrewarding inflorescence did not significantly change through experiments. Selfing rates for unrewarding inflorescences were predicted to depend principally on the number of these inflorescences bumblebees visited rather than on the number of flowers they visit per inflorescence. This was because most visitors to orchids are supposed to be naive, and pollinators that commence foraging carrying no pollen will necessarily self any flower they pollinate on the first inflorescence they visit. Thus the average selfing rate is expected to increase as the sequence of inflorescences visited decreases in length.     

Taxonomic position and distribution of Atriplex lapponica (Chenopodiaceae)

The arctic, halophytic species Atriplex lapponica Pojark has flowers of two kinds: perfect ones surrounded by a pentamerous perianth and pistillate flowers enclosed in bracteoles. Thus, A. lapponica is closely related to the species of sect. Dichospermum Dumort, not to species of sect. Teutliopsis Dumort. as generally believed.     

Energy requirements of fat sand rats (Psammomys obesus) and their efficiency of utilization of the saltbush Atriplex halimus for maintenance

The fat sand rat (Psammomys obesus; Gerbillinae), a diurnal gerbillid rodent, is herbivorous and able to thrive while consuming only the saltbush Atriplex halimus (Chenopodiaceae), a plant relatively low in energy content and high in ash and water. We measured the basal metabolic rate offat sand rats, their energy requirements in captivity when they were offered only A. halimus, and their efficiency of utilization of this diet for maintenance.
Before consuming A. halimus leaves, the fat sand rats scraped off the surface layers with their teeth. This behavioural activity removed 6.4% to 8.5% of the dry matter of the leaf, but increased the gross energy and organic matter content of the leaf by only approximately 3.1%. Basal metabolic rate of the fat sand rats was 167.9 kJ.kg-O 7s d-', approximately 57% of that expected for an eutherian mammal of its body mass, and energy requirements for maintenance, or average daily metabolic rate, were 498.7 kJ.kg-0'7s d-', approximately 90% of that expected for a rodent of its body mass. Dry matter digestibility of the consumed A. halimus averaged 67% and apparent digestible energy and apparent metabolizable energy averaged 65.3% and 63.4% of the gross energy, respectively. The efficiency of utilization of A . halimus for maintenance energy (k,) by the fat sand rats was 0.32 and the heat increment of feeding (HIF) was 0.68. The k, of A. halimus appeared to be low compared to other feeds, and this characteristic plus its low energy value and high water content forced the fat sand rats to consume large quantities of forage for maintenance.
It was concluded that although A. halimus has a low energy and high ash content, there are several advantages for fat sand rats consuming mainly this diet. Among them are: (1) it provides a more stable diet throughout the year than do seeds; (2) fat sand rats have no competition for this food resource from other rodents; and (3) their burrows are at the base of the     

Molecular phylogeny of Atripliceae (Chenopodioideae, Chenopodiaceae): Implications for systematics, biogeography, flower and fruit evolution, and the origin of C4 photosynthesis

? Premise of the study: Atripliceae (Chenopodiaceae), including Atriplex (300 spp.) as the largest genus of the family, are an ecologically important group of steppes and semideserts worldwide. Relationships in Atripliceae are poorly understood due to obscure and potentially convergent morphological characters. ? Methods: Using sequence variation of two chloroplast markers (rbcL gene, atpB-rbcL spacer) and one nrDNA marker (ITS) analyzed with BEAST, we investigated the systematics and biogeography of Atripliceae. We surveyed flower morphology and fruit anatomy to study the evolution of flowers and fruits in the tribe. ? Key results: Female flowers with persistent foliar cover (the diagnostic character of traditional Atripliceae) evolved three times in Chenopodioideae, in Atripliceae s.s., Axyrideae, and Spinacia. Atripliceae s.s. started to diversify during the Early Miocene in Eurasia, separating into the Archiatriplex and the Atriplex clades. The former consists of eight species-poor, disjunct, and morphologically heterogeneous genera and is likely a relictual lineage. The Atriplex clade comprises the majority of species and evolved one C(4) lineage 14.1-10.5 Ma, which diversified rapidly worldwide. The C(4) Atriplex entered North America during the Middle/Late Miocene and spread to South America subsequently. Australia was colonized by two C(4) lineages both arriving during the Late Miocene. One of them diversified rapidly, giving rise to most Australian Atriplex species. ? Conclusions: Atripliceae s.s. comprise Archiatriplex, Atriplex, Exomis, Extriplex, Grayia, Halimione, Holmbergia, Manochlamys, Proatriplex, and Stutzia. Microgynoecium is included based on morphology but only weak molecular support. Axyris, Krascheninnikovia, and Ceratocarpus (here described as Axyrideae) and Spinacia are excluded from Atripliceae.     

Spiradiclis jingxiensis sp. nov. (Rubiaceae) from Guangxi,China

The new species Spiradiclis jingxiensis R. J. Wang is described here. It is similar to S. danxiashanensis with respect to its prostrate habit, small leaves, and terminal inflorescence with 1–3 salverform flowers, but is readily distinguished by pinkish flowers, and included stamens and stigmas in long‐ and short‐styled flowers. The conservation status of the new species was preliminarily assessed as ‘EN’ according to IUCN categories and criteria.     

EVOLUTIONARY STUDIES OF ATRIPLEX: PHYLOGENETIC RELATIONSHIPS OF ATRIPLEX PLEIANTHA

Atriplex pleiantha Weber differs from all other species of Atriplex in having 1) multiple female flowers subtended by two bracts, 2) female flowers with a perianth, and 3) embryos with radicles pointing downwards. Because of these significant differences it is proposed that Atriplex pleiantha be elevated to the level of a separate genus and be designated Proatriplex pleiantha (Weber) Stutz & Chu. The closest relatives of Proatriplex appear to be Archiatriplex, Endolepis, Exomis, and Microgynoecium. These are all diploid, monoecious annuals, have non-Kranz type leaf anatomy, and female flowers with a perianth.     

Unisexual flowers as a robust synapomorphy in Cariceae (Cyperaceae)? Evidence for bisexual flowers in Schoenoxiphium

Cariceae, the largest tribe within Cyperaceae, comprises about 2000 species in five genera. Cariceae is usually considered to be distinct from other Cyperaceae by the presence of exclusively unisexual flowers and by the arrangement of the pistillate flowers in single-flowered spikelets that are enclosed by the flask-like spikelet prophyll (utricle or perigynium). The nature of several morphological features of the Cariceae inflorescence remains controversial. The staminate reproductive units, as well as earlier reported bisexual reproductive units in Schoenoxiphium have been considered to be reduced partial inflorescences, or flowers. Aims of this study are to test both interpretations, based on a floral ontogenetic investigation. Moreover, for the first time, detailed SEM micrographs are presented of the inflorescence and floral development and of bisexual flowers in Schoenoxiphium. We propose that ‘inhibition of bisexuality’ is a more robust synapomorphy in Cariceae than ‘presence of only unisexual flowers’.     

贵州杜鹃花属（杜鹃花科）一新种——荔波杜鹃

描述了贵州杜鹃花属（杜鹃花科）一新种———荔波杜鹃Rhododendron liboense Z.R.Chen&K.M.Lan。该种以花序顶生,花冠粉红色,宽钟状,子房密被白色腺毛,柱头头状而近似于凉山杜鹃R.huianum Fang,但叶片狭窄,宽1.6-2.8cm,花序轴长1-3cm,花7-9朵,花冠较大,直径约8cm,花萼短小,长仅1-2mm而不同。     

Phacelophrynium sapiense (Marantaceae) a new species from Sabah, Malaysia

Phacelophrynium sapiense , a new species from Sabah, Malaysia, is described and illustrated. It differs from other known Phacelophrynium species in its light green to yellow leaf variegation, purple leaf underside, creamy white inflorescence and cream white flowers. The species is furthermore unusual in having a pair of membranaceous bracteoles associated with each flower, a feature otherwise known only in species of the New World genus Calathea.     

Reclamation of highly calcareous saline sodic soil using Atriplex halimus and by-product gypsum

The removal of sodium salts from saline soils by salt tolerant crops, as alternative for costly chemical amendments, has emerged as an efficient low cost technology. Lysimeter experiments were carried out on a highly saline sodic soil (ECe = 65.3 dS m(-1), ESP = 27.4, CEC = 47.9 cmole+ kg(-1), and pH = 7.7) and irrigated with canal water (EC = 2.2 dSm(-1), SAR = 4.8) to investigate reclamation efficiency under four different treatments: control (no crop and no gypsum application) (C), gypsum application equivalent to 100% gypsum requirement (G100), planting sea orach (Atriplex halimus) as phytoremediation crop (Cr), planting sea orach with gypsum application equivalent to 50% gypsum requirement (CrG50). Soil salinity (ECe) and exchangeable sodium percentage (ESP) were significantly reduced compared to the control. Average ESP and ECe (dS m(-1)) in the top layer were 9.1, 5.8 (control), 4.8, 3.7 (Cr), 3.3, 3.9 (CrG50), and 3.8, 3.1 (G100), respectively. Atriplex halimus can be recommended as phytoremediation crop to reclaim highly saline sodic clay loam soils.     

AN ANATOMICAL BASIS FOR THE DIVERGENT FLORAL FORMS IN THE CLEISTOGAMOUS SPECIES,LAMIUM AMPLEXICAULE L. (LABIATAE)

The pattern of variation in mature corolla form has been documented throughout the main shoot inflorescence of the cleistogamous species Lamium amplexicaule L. A heteroblastic development occurs within the cymose inflorescence at a single node as well as between different nodes. Variation involves an increase in cell number and expansion in the upper corolla and also an increase in cell number in the anther sacs, expressed as pollen count increases, in progressively produced flowers in the inflorescence. The corolla base region in all flowers shows an increased cell expansion from the first produced cleistogamous (CL) flowers to the later produced chasmogamous (CH) flowers which expand at anthesis. Cell numbers are equivalent in the corolla base region of all flowers. It appears that in successively produced flowers in the inflorescence, prolonged cell division and expansion occurs in both the upper corolla region and the anthers until a threshold is reached, at which point flowers may undergo anthesis and become CH. The CL corolla form in Lamium amplexicaule is not caused by a lack of cell expansion alone; rather, both cell division and expansion are arrested in the upper corolla region.     

Pseudoracemes in papilionoid legumes: their nature, development, and variation

Pseudoracemes in papilionoid legumes: their nature, development, and variation. Cymelike partial inflorescences called fascicles have been reported in the inflorescences of several papilionoid tribes. The total inflorescence is termed a ‘pseudoraceme’ because of the multiple flowers in each bract axil. Pseudoraceme development has been studied in 22 taxa in five papilionoid tribes (Abreae, Desmodieae, Millcttieae, Phaseoleae and Psoraleeae). Two to twelve flowers occur per bract axil among various taxa, with three the most common number.Pongamia pinnata and Clitoris fairchildiana have only two flowers per axil; Vigna radiata, Phaseolus vulgaris, and Apios americana have four to five commonly, and Dioclea aff.ucayalina and Abrus precalorius have up to 12. The ‘fascicle’ usually consists of a triad of three flowers; each triad resembles a dichasial cyme in that the middle flower appears terminal. The middle flower however is subtended by a bract on the abaxial side, so that the middle flower is technically lateral. When the first-order axis elongates, each triad may either remain intact or be separated by axis intervalS. Many variations on the basic triad pattern occur in the species studied: 1.one or two flowers may develop while others that are initiated remain suppressed; 2. Additional flowers may be produced that replicate the first triad; 3. Additional flowers may form medianly only, on the abaxial side. The second-order inflorescence axis which has produced the three flowers persists to produce more flowers in replication of the triad pattern in several taxa (Apios americana, Vigna radiata, Phaseolus vulgaris, and Dioclea aff.ucayalina). In Butea monosperma the second-order inflorescence apex produces subsequent flowers (after the triad) in a helix. In Erylhrina perrieri, there is no indication of a persistent second-order inflorescence apex after the central flower; such a condition could be interpreted as a cyme, except for the abaxial subtending bract. The triad in Psoralea pinnata is a true cyme; the middle flower lacks a subtending bract other than that subtending the entire fascicle. Developmentally, the difference between a cyme and an early-determinate raceme (as in the triad type of pseudoraceme) is rather slight. Comparison of the types of inflorescences described here may indicate how the transition may have occurred between racemes and cymes in the evolution of legumes.     

Organographic and ontogenetic studies on the inflorescence ofLespedeza cuneata (Dum.-Cours.) G. Don (Leguminosae)

Structure of inflorescence and its variation were organographically and ontogenetically studied inLespedeza cuneata (Dum.-Cours.) G. Don. An axillary inflorescence of the species forms a compound inflorescence which is composed of three or four component inflorescences. Each component inflorescence bears four (rarely six), three, two, or one flowers. Based on the arrangement of inflorescence phyllomes, the component inflorescence with four flowers is interpreted as a pseudoraceme bearing two shortened lateral shoots (partial inflorescences) each of which has two flowers. The component inflorescence with one flower appears to be terminated by the flower and to compose the cyme. Organographic observations revealed that the terminally located flower is not truly terminal, but axillary in origin. Ontogenetic observations showed that the apices of component inflorescence and partial inflorescence exist in early developmental stages in spite of variation in the form of component inflorescence. The terminally located flower in the cyme-like inflorescence was thus demonstrated to be laterally borne on the partial inflorescence axis. The component inflorescence composing the cyme-like one inL. cuneata is a reduced form in the number of partial inflorescences and of flowers from the pseudoraceme. The cyme-like inflorescence inL. cuneata resembles the inflorescence ofKummerowia.