Old World and New World Cupressus pollen: morphological and cytological remarks

The aim of this work was to collect new information about pollen morphology and pollen wall structure comparing Cupressus species from the Old World and New World. Cupressus is a nonmonophyletic genus that includes species that appear to be divided into Old World and New World clades. Observations in this study on cypress pollen indicate that grain size and composition of intine β-glucans are different between the considered Old World and New World species. Different from all the other American cypress species, pollen of C. macrocarpa reacted to dying in a similar manner to Old World species. Rehydrated pollen grains collected from 20 Asian, Afro-Mediterranean and American cypress species were measured under a light microscope. The size of the pollen grains and the percentage of intine in relation to the pollen grain diameter were significantly different between Old World and New World species. Pollen wall composition was tested after addition of different dyes to the hydration solution, and subsequent observations were carried out by light and fluorescence microscopy. Lugol and calcofluor staining showed differences in composition of the middle and inner intine layers between New World and Old World species.     

Nucellar beak structure and pollen tube growth in Cucurbitaceae

The nucellar beak is a proboscis-like outgrowth of the nucellus at the micropylar end, being the obligatory path for the pollen tube entering the ovule. Among the few angiosperm families with nucellar beak, Cucurbitaceae is remarkable because the pollen tube may develop at least two types of growth within the nucellar beak: tubular and ampulliform. Wondering about the possibility that Cucurbitaceae ovules may express some histological variation that could be related to pollen tube growth within the nucellar beak, we performed a compared anatomical and histochemical study of the nucellar beak and the pollen tube growth of ten species of Cucurbitaceae. Results show that Cucurbitaceae ovules are diverse in size and proportions (of integuments, nucellar body, and nucellar beak), and they have at least four types of nucellar beak histology: pectic-tracked, secretory-like, amylaceous, and mixed. Amylaceous and mixed nucellar beaks are related to the ampulliform growth of the pollen tube, which could have appeared independently in most derived tribes of Cucurbitaceae, although information about nucellar beak structure in the basal tribes is still needed. In addition, the understanding of the relation between amylaceous nucellar beaks and the ampulliform growth of the pollen tube, whose function is still to be discovered, might open the possibility of a unique model of pollen tube-ovule co-evolution in angiosperms.     

Plastid differentiation during Cucurbita pepo (Cucurbitaceae) pollen grain development

The development of plastids in the pollen of Cucurbita pepo was followed from meiosis to pollen maturation by quantitative light and electron microscopy. Plastids are initially undifferentiated, then divide, and at late microspore stage differentiate into amyloplasts containing starch. Later the amyloplasts form lobes and divide. Amyloplasts containing a single starch grain are present from the early bicellular stage. Plastid development is considered in relation to such cytoembryological features as the pollen does not dehydrate at anthesis and germination begins 3 min after pollination.     

A new species of Zehneria (Cucurbitaceae) from Somalia

The new species Zehneria somalensis , from shady limestone rocks in north-eastem Somalia, is described and illustrated.     

A new species of Momordica (Cucurbitaceae) from tropical Africa

Momordica littorea , sp. nov., a dioecious climber with succulent 3-foliolate leaves and conspicuously bracteate flowers from coastal regions of southern Somalia and Kenya, is described and illustrated.     

蓼属-未知花粉类型外壁超微结构的研究

花粉壁的构造提供了若干在系统发育上有用的特征,其中外壁的层次、结构以及纹饰是基本的。为此,本文以花粉壁的外部纹饰和内部结构为重点,用扫描电镜（ＳＥＭ）和透射电镜（ＴＥＭ）的薄切片技术,对蓼属一新的花粉类型－－长花蓼型的花粉外壁构造的特点进行了观察和研究。结果表明：外壁结构分化成两个明显的层次,即外面的外壁外层以及内面的外壁内层,其外壁外层无覆盖层,仅由柱状层和底层组成的。     

Two new species and a new combination in Frantzia (Cucurbitaceae)

The monotypic genusPolakowskia is reduced to a section ofFrantzia. Two new species from Costa Rica,F. villosa andF. talamancensis, are described. The new nomenclatural combination,F. tacaco (Pittier) Wunderlin, is proposed.     

A new species of Sicyos (Cucurbitaceae) from Chiapas,Mexico

Sicyos motozintlensis is described from the vicinity of Motozintla de Mendoza, Chiapas. It shows a strong similarity toS. chiriquensis Hammel & D’Arcy from Panama.     

A new adhesive for airborne pollen sampling

There is a spreading interest to establish networks of information exchange on aerobiological data in order to carry out comparative studies of the biological air content of different regions. For this kind of study, it is of primary importance that the methods used are being standardized. Since most national networks are now made of comparable Hirst-type samplers, the second most important factor to consider will be the efficiency of the adhesive used on the Melinex tape. In this study, we report conclusive results using a double-side self adhesive acrylic tape (Scotch 3M 9425). Our results show higher capture efficiency (+20%) for the 3M tape as compared to the glycerine/gelatine coating traditionally used in Montréal for the capture of airborne pollen on the Melinex tape of Hirst samplers.     

A new procedure to asses pollen viability

We tested pollen viability of eight species using four vital dyes, a new peroxidase test together with three other established methods (MTT, Baker’s and X-Gal), to determine their potential to differentiate fresh pollen from pollen heated for 2 h and 24 h at 80°C (killed pollen) and compared the results with in vitro germination. We found that two of three dyes previously employed to determine viability also stained killed pollen, while the new peroxidase test and MTT did not. We suggest that the latter two are the best methods to test pollen viability, since they do not normally stain either killed or aborted pollen. Received: 7 May 1999 / Revision accepted: 25 October 1999     

A mobile element based phylogeny of Old World monkeys

SINEs (Short INterspersed Elements) are a class of non-autonomous mobile elements that are <500 bp in length and have no open reading frames. Individual SINE elements are essentially homoplasy free with known ancestral states, making them useful genetic systems for phylogenetic studies. Alu elements are the most successful SINE in primate genomes and have been utilized for resolving primate phylogenetic relationships and human population genetics. However, no Alu based phylogenetic analysis has yet been performed to resolve relationships among Old World monkeys. Using both a computational approach and polymerase chain reaction display methodology, we identified 285 new Alu insertions from sixteen Old World monkey taxa that were informative at various levels of catarrhine phylogeny. We have utilized these elements along with 12 previously reported loci to construct a phylogenetic tree of the selected taxa. Relationships among all major clades are in general agreement with other molecular and morphological data sets but have stronger statistical support.     

A new adhesive for airborne pollen sampling in Spain

The use of a double-sided self-adhesive tapefor pollen trapping could offer some advantagesover traditional adhesives, manually applied tothe Melinex tape of a Hirst-type spore trap,since variation in terms of adhesiveapplication is nil and additional effort inapplying the adhesive is avoided. Nevertheless,its efficiency with respect to the standardadhesives must be tested. In Cordoba (southwestSpain), the Spanish Aerobiology Network Centreperformed a series of comparative studies andrecommended the use of a silicone fluid as anadhesive. This paper compares the efficiency ofa double-sided self-adhesive tape (3M) withsilicone fluid as adhesive. Sampling wascarried out using a Hirst type 7-day spore traplocated 15 m above ground level. A Melinex tapecoated with silicone fluid covered one half ofthe weekly drum; the other half was coveredwith 3M tape that included the adhesive. It iswidely reported that the physicalcharacteristics of silicone fluid do not varywith temperature (Galán andDomínguez-Vilches, 1997), but this studyshowed that 3M efficiency did vary withtemperature. The results revealed that 3M tapewas less efficacious at low temperatures, whileat high temperatures it becomes stickier. Incontrast, silicone fluid does not vary withtemperature. The efficiency of 3M tape alsoseems to be negatively influenced by rain.     

Effects of soil phosphorus on pollen production,pollen size,pollen phosphorus content,and the ability to sire seeds in Cucurbita pepo (Cucurbitaceae)

To determine the effects of soil phosphorus on pollen production, pollen grain size, phosphate concentration per pollen grain, and the siring ability of pollen, two cultivars of the common zucchini (Cucurbita pepo) were grown under two soil phosphorus conditions in an experimental garden. Overall, soil phosphorus availability had a significant effect on reproductive output through the female function and on traits affecting the male function of plants (staminate flower production, pollen production per flower, and pollen grain size). In addition, pollen produced by plants in the high phosphorus soils had a higher phosphate concentration than pollen produced by plants in the low phosphorus soils. A pollen mixture experiment revealed that pollen produced by plants in the high phosphorus treatment sired significantly more seeds than pollen produced by plants in the low phosphorus treatment. This study showed that growing conditions such as soil phosphorus can influence the size of a pollen grain and its chemical composition, which, in turn, can affect its ability to sire mature seeds.     

A review of the Cucurbitaceae

Progress in studies of Cucurbitaceae since 1964 is reviewed, particular attention being paid to the roles of seed-coat anatomy, palynology and phytochemistry in elucidating the taxonomy of the family; to the use of wild species and land-races as sources of horticulturally desirable traits for the improvement of crops; to the potentialities of wild species for domestication as new crops for tropical areas, and to the biology of reproduction, sex control and sex expression. The classification of the lady is outlined, illustrated by discussion of the more important members of each tribe, and a revised classification of Cucumis is presented.     

A new technique for monitoring pollen flow in orchids

Summary The orchid Prasophyllum fimbria is pollinated by nectar-feeding native bees and wasps. The pollinia are patially separated from the viscidium by a stipe so that pollinia can be labelled with coloured histochemical stains without interfering with pollinarium removal. Pollen flow was monitored by following the movement of the coloured pollen in several populations of P. fimbria in Western Australia. Statistical analysis confirmed that pollen labelling did not interfere with pollinarium removal or subsequent pollination of the labelled flower. Fifty eight labelled pollinaria were removed by vectors from 16 test spikes, with a total of 125 flowers on 47 spikes receiving labelled pollen. An average of 2 flowers received pollen for every pollinium removed but up to 6 flowers received pollen from a single collinium. No significant differences between mean vector flights and pollen flow distances were detected. On average, geitonogamous transfers only accounted for 22% of all pollinations. This is a simple and inexpensive technique for the direct labelling of pollen with minimal disruption to the pollination system and may have applications in other plant families.     

Reproductive physiology in female Old World Camelids

This review summarizes the basic reproductive physiology of dromedary and Bactrian camels. Camels are seasonal breeders with a relatively short breeding season during the cooler months. The onset of the breeding season can be influenced by local environmental factors such as temperature and pasture availability although decreased libido of the male as the environmental temperature increases is also a factor. Oestrous behaviour is highly variable in duration and intensity and is therefore unreliable for the detection of oestrus and difficult to relate to follicular activity in the ovaries. Camels are induced ovulators and thus normally only ovulate in response to mating. In the absence of mating, ovarian follicles tend to regress after a period of growth and maturity, whereas if male and females are kept together the female gets mated when the dominant follicle measures between 1.3 and 1.7 cm in diameter and the corpus luteum that develops has a lifespan of only 10-12 days. Peripheral concentrations of oestradiol increase with increasing follicle diameter until the follicle reaches 1.7 cm in diameter at which time they start to decrease even if the follicle continues to grow. The concentrations of progesterone remains low in non-mated animals but in mated camels it increases 3-4 days after ovulation (day of ovulation=Day 0) to reach maximum concentrations on Days 8-9 before decreasing rapidly on Days 10-11 in the non-pregnant animal. Ovulation can also be reliably induced using either Gonadotrophin Releasing Hormone (GnRH) or human Chorionic Gonadotrophin (hCG) but only when the follicle measures between 1.0 and 1.9 cm in diameter. Ovulation does not typically occur from follicles that grow beyond 2.0 cm in diameter but these follicles typically develop echogenic strands of fibrin as the follicle degenerates. The gestation period of camels is 13 months but the time of resumption of follicular activity following parturition is highly variable and influenced by nutritional status and lactation. Females that lose their offspring or have offspring which are weaned have a mature follicle develop within 10-12 days, whilst in well-fed lactating females mature follicles do not develop until 30-60 days postpartum.     

Brain evolution in Old World monkeys.

Sulcal patterns of 14 genera of Old World monkeys were analyzed from 107 endocasts. Colobines and cercopithecines differ in patterns of cerebral convolutions, and functional and evolutionary hypotheses are here proposed regarding those differences. The cercopithecine pattern seems to be the more derived since it suggests relative expansion of prefrontal, and inferior temporal integration cortices as compared to the colobine pattern.