Carex ×payettei, a new hybrid of Carex sect. Racemosae described from subarctic Quebec, Canada (Cyperaceae)

A new hybrid is described between two boreal species of Carex sect. Racemosae, the North American Carex atratiformis and the circumboreal Carex media, under the name of Carex ×payettei. It is reported in Nunavik (Northern Quebec, Canada), in nine localities within the Forest Tundra and Open Boreal Forest zones. It is intermediate in morphology between the parental species and is not completely sterile, frequently producing fruits. Pollen stainability of the hybrid varied between 10% and 37% while its parents display values above 95%.

Morphological and Cytological Characterization of Five Porterweed (Stachytarpheta) Selections

Porterweed (Stachytarpheta spp.), a member of the verbena family, is frequently used in pollinator gardens to attract butterflies. This study was conducted to assess the morphological features, pollen stainability and morphology, nuclear DNA content, and chromosome number of five porterweed selections. Coral porterweed (S. mutabilis), ‘Naples Lilac’ porterweed (S. cayennensis × S. mutabilis ‘Violacea’), and nettleleaf porterweed (S. cayennensis) had the largest plant heights. Flower number was significantly higher in nettleleaf porterweed, jamaican porterweed (S. jamaicensis), and U*J3-2 porterweed (S. cayennensis × S. jamaicensis), with an average of 65–72 flowers per inflorescence. Internode length and flower width of jamaican porterweed had much lower values than the other selections. Coral porterweed recorded the lowest pollen stainability with only 10.6% stainability, but it had the largest relative pollen production. ‘Naples Lilac’ porterweed had the highest DNA content with an average of 3.79 pg/2C, like jamaican porterweed with 3.73 pg/2C. Ploidy levels varied between selections, and the basic chromosome number was x = 28. Coral, jamaican, and ‘Naples Lilac’ porterweed had 2n = 6x = 168 chromosomes, first reported in this genus. These results provide a guide and a new tool to distinguish native and non-native porterweed and may aid future breeding toward the production of noninvasive cultivars.

Meiotic behavior and diploidy in Schinus terebinthifolia (Anacardiaceae)

The genus Schinus (Anacardiaceae) comprises 30 species found in Peru, Bolivia, Chile, Paraguay, Uruguay, Argentina and Brazil. Schinus terebinthifolia (Brazilian pepper tree) is socioeconomically important in the Brazilian state of Espírito Santo. Dried fruit is used as a pepper-like spice and natural populations are exploited. Studies on the meiotic behavior and pollen stainability from an ecological and evolutionary point of view are essential, since they can promote future sustainable management strategies for this species. The objective was to evaluate meiotic behavior and characteristics of pollen grains of individuals from a natural population of S. terebinthifolia localized in the municipality of Vitória, Espírito Santo state, Brazil. Young anthers were squashed in 1% acetocarmine dye to obtain the pollen mother cells. The pollen stainability with 1% acetocarmine, Lugol’s iodine solution and Sudan IV and pollen shape were used to assess the pollen potential viability, cytochemistry and morphology. All individuals had a gametic number of n = 7, a regular meiotic behavior and so the somatic number is 2n = 2x = 14 chromosomes. Median pollen stainability was 94%. Pollen grains are dispersed as monads, 3 - colporate and subspheroidal. The exine has striate-reticulate ornamentation. Pollen grains are starch positive and lipid negative. This is the first report of the occurrence of diploidy for the species. The high pollen stainability is the result of the occurrence of regular meiosis. The presence of starch as pollen reserve can increase the resistance of pollen grains to hostile environments in this species.

Morphological and Cytological Comparisons of Eight Varieties of Trailing Lantana (Lantana montevidensis) Grown in Florida

Trailing lantana (Lantana montevidensis) is a popular low-growing ornamental plant valued for its heat and drought tolerance and continuous purple or white flowering throughout much of the year. Recently, trailing lantana was predicted to be invasive by the University of Florida/Institute of Food and Agricultural Sciences (UF-IFAS) Assessment of Non-Native Plants in Florida, and therefore not recommended for use. All cultivars fall under this designation unless proven otherwise. Eight trailing lantana varieties were obtained from wholesale growers and naturalized populations found in Texas and Australia. Plants were propagated vegetatively, finished in 4-inch pots, and planted under field conditions to determine morphological and cytological differences among varieties. Australian trailing lantana differed morphologically from the other varieties in its smaller habit, leaves (which had serrate-crenate leaf margins, and fewer appressed hairs), heavy fruiting, and cold sensitivity (observational reduced growth and flowering during winter months). Nuclear DNA content analysis suggests that Australian trailing lantana is likely a tetraploid and all other varieties evaluated were likely triploids with high levels of sterility. Pollen stainability of Australian trailing lantana was moderately high (58.83%), whereas pollen production was rarely observed in all other varieties. Results support that there are two forms of trailing lantana, the U.S. varieties distinguished by their leaf and flower morphology, ploidy level, and the absence of fruit and viable pollen.

Hybridization in Four Nigerian Physalis (Linn.) Species

Interspecific reciprocal crosses among four Nigerian Physalis species (Physalis angulata, P. micrantha, P. pubescens and P. peruviana) were carried out by transferring desired pollen grains to ovalate parents, bagged and labelled to prevent contamination by external pollen grains and for easy identification. Pollen cells of the F1 hybrid combination from the only viable cross (P. angulata x P. pubescens) were studied using standard cytogenetic techniques. The F1 hybrid obtained in the current investigation produced few flower buds and no matured fruit was harvested. Its average pollen grain diameter was found within the range of that of the two genitors and the pollen stainability was less than 50%. The hybrid was also characterized by meiotic irregularities. Based on the results obtained, the study concluded that P. pubescens is closely related to P. angulata and P. peruviana, while P. micrantha is more distant from them since the formal individuals were able to cross reciprocally among each other, though no matured fruit was produced except in one cross (P. angulata x P. pubescens).

Reproductive Biology in Northern Prickly Ash

Zanthoxylum americanum is a common understory species in the northern forests of Minnesota and surrounding regions. It has potential economic importance for its citrus fragrance, pharmacological or insecticidal properties, and produces peppercorns similar to those of the related Zanthoxylum species. Zanthoxylum americanum is a dioecious species but has been reported to have aberrant flowers with autonomous apomixis instead of other potential reproductive barriers. The reproductive biology of Zanthoxylum americanum was investigated in two native Minnesota populations. Determinations of male fertility, whether autonomous apomixis was the predominant floral reproductive mechanism, the presence of seedless fruit (parthenocarpy/stenospermocarpy), and the occurrence of hermaphrodism were made over 2 years. Sex ratios (female:male plants) within each population differed. The mean pollen stainability was 95.8% ± 0.3% (fresh) and 78.6% ± 1.1% (stored 18 months). Parthenocarpy did not occur in either population. Autonomous apomixis was not the primary floral reproductive mechanism. Stenospermocarpy (seedlessness) occurred in 13% of the female fruit clusters. Although commonly described as being dioecious, two additional reproductive strategies were identified: 1) plants with functional protandrous flowers with rudimentary pistils and 2) hermaphroditic flowers with fully functional pistils (protogynous) and anthers. As many as 10% to 30% of the male plants bore at least one fruit/plant each year. One clonal stand had both hermaphroditic and functionally staminate flowers on the same plant. Two evolutionary pathways to dioecy in Z. americanum are proposed.

Limonium ilergabonum (Plumbaginaceae), a new species from northeastern Iberian Peninsula

A new species of Limonium (Plumbaginaceae), L. ilergabonum sp. nov., is described from the inland gypsum soils of the northeastern Iberian Peninsula (Flix, Tarragona province, Spain). The new species is closely related to the Iberian L. hibericum on morphological traits as assessed by multivariate ordination analysis (PCA), but it can be distinguished by the narrower leaves, inflorescence shape, and longer calyx. Limonium ilergabonum shows mixoploidy (2n = 18, 2n = 27), irregular pollen shapes, low levels of pollen stainability, and a single pollen-stigma combination morph (B type). All evidences suggest that L. ilergabonum is a polyploid relict species with an apomictic breeding system that has been originated from 2n = 18 ancestors, but to date any known extant diploid species may be suggested as a likely parental species.

Cytological Studies on Two Species, Xanthium strumarium Linn. and Bidens pilosa Linn. Var. minor (Blume) Sherff (Asteraceae-Heliantheae) from Nepal

Karyotype, meiosis and pollen stainability of the taxa Bidens pilosa L. var. minor (Blume) Sherff and Xanthium strumarium L. collected from central part of Nepal was cytologically carried out. Results obtained from this investigation showed that chromosome number in somatic cells were recorded to be 2n=36 in Bidens pilosa and 2n=32 in Xanthium strumarium using aceto-orceine squash technique. Likewise haploid chromosome number in reproductive cells were recorded to be n=18 in Bidens pilosa and n=16 in Xanthium strumarium using aceto-carmine squash technique. The range of chromosome length found to be 0.4 to 2.1 µm in Bidens pilosa and 0.4 to 1.6 µm in Xanthium strumarium. Karyotype formula was M16+m2+sm14+st4 for Bidens pilosa and M18+ sm12+st2 for Xanthium strumarium. Based on the position of the centromeres, the chromosomes were categorized into four types with centromere at median point, median region, sub median region and terminal region in Bidens pilosa whereas three types, namely chromosomes with centromere at median point, sub median region and sub terminal region in Xanthium strumarium . In Bidens pilosa karyotype is asymmetrical and slightly asymmetrical karyotype is found in Xanthium strumarium. Absolute length recorded in Bidens pilosa were 19.2µm and 15.8. µm in Xanthium strumarium . Pollen stainability is found to be 94.0 percent in Bidens pilosa and 92.7 percent in Xanthium strumarium.Int. J. Appl. Sci. Biotechnol. Vol 5(1): 66-71