Genetic Differentiation of Reed Canarygrass ( L.) within Eastern Europe and Eurasia.

Worldwide molecular research of economically important (Poaceae) is mainly focused on the invasions of this species from Europe to North America. Until the present study, the genetic diversity of the had not been studied across the Baltic countries. The objective of this research is to evaluate the diversity of Lithuanian populations of at simple sequence repeat (SSR) loci comparatively among populations of the Baltic countries, Luxembourg, and the Russian Far East (Eurasian), evaluating differentiation between Lithuanian populations and ornamental accessions, and relating these with environmental features.

Phenotypic differences among and within extant populations of Chrysanthemum arcticum L. and C. a. subsp. arcticum.

Background: Chrysanthemum arcticum, arctic daisy and its two subspecies (Chrysanthemum arcticum subsp. arcticum, Chrysanthemum arcticum subsp. polaré) are the only chrysanthemum species native to North America.

Variability in ITS1 and ITS2 sequences of historic herbaria and extant (fresh) Phalaris species (Poaceae).

Background: Phalaris species (Poaceae) occupy diverse environments throughout all continents except Antarctica. Phalaris arundinacea is an important forage, ornamental, wetland restoration and biofuel crop grown globally as well as being a wetland invasive. The nuclear ribosomal internal transcribed spacer (ITS) region has been used for Phalaris barcoding as a DNA region with high nucleotide diversity for Phalaris species identification.

How many marker loci are necessary? Analysis of dominant marker data sets using two popular population genetic algorithms.

The number of marker loci required to answer a given research question satisfactorily is especially important for dominant markers since they have a lower information content than co-dominant marker systems. In this study, we used simulated dominant marker data sets to determine the number of dominant marker loci needed to obtain satisfactory results from two popular population genetic analyses: STRUCTURE and AMOVA (analysis of molecular variance). Factors such as migration, level of population differentiation, and unequal sampling were varied in the data sets to mirror a range of realistic research scenarios.

The transmitting tissue of Nicotiana tabacum is not essential to pollen tube growth, and its ablation can reverse prezygotic interspecific barriers.

The Nicotiana tabacum transmitting tissue is a highly specialized file of metabolically active cells that is the pathway for pollen tubes from the stigma to the ovules where fertilization occurs. It is thought to be essential to pollen tube growth because of the nutrients and guidance it provides to the pollen tubes. It also regulates gametophytic self-incompatibility in the style.

PELPIII: the class III pistil-specific extensin-like Nicotiana tabacum proteins are essential for interspecific incompatibility.

Pre-zygotic interspecific incompatibility (II) involves an active inhibition mechanism between the pollen of one species and the pistil of another. As a barrier to fertilization, II effectively prevents hybridization and maintains species identity. Transgenic ablation of the mature transmitting tract (TT) in Nicotiana tabacum resulted in the loss of inhibition of pollen tube growth in Nicotiana obtusifolia (synonym Nicotiana trigonophylla) and Nicotiana repanda.

A novel pollen tube growth assay utilizing a transmitting tract-ablated Nicotiana tabacum style.

Sexual plant reproduction requires multiple pollen-pistil interactions from the stigma (pollen adhesion, hydration, and germination) to the ovary (fertilization). Understanding the factors that regulate pollen tube growth is critical to understanding the processes essential to sexual reproduction. Many pollen tube growth assays (PTGAs) have shorter and slower pollen tube growth when compared to pollen tube growth through the style.