Reduction in chiasma frequency and pollen fertility due to multiple chromosomal associations and univalents inSaxifraga diversifoliafrom alpine regions of northwest Himalayas (India)

Two accessions were studied for male meiosis inRanunculus laetusfrom the cold regions of Northwest Himalayas. One accession showed the presence of 14 bivalents at diakinesis and regular segregation of bivalents at anaphase I which lead to normal tetrad formation with fournmicrospores and consequentlynpollen grains and 100% pollen fertility. Second accession from the same locality revealed the erratic meiosis characterized by the presence of all the 28 chromosomes as univalents in meiocytes at metaphase I. Univalent chromosomes failed to segregate during anaphases and produced restitution nuclei at meiosis I and II. These restitution nuclei resulted into dyads and triads which subsequently produced two types of apparently fertile pollen grains. On the basis of size, the two types of pollen grains were categorized asn(normal reduced) and2n(unreduced, 1.5-times larger than thenpollen grains). The estimated frequency of2npollen grains from dyads and triads (61.59%) was almost the same as that of the observed one (59.90%), which indicated that2npollen grains inR. laetuswere the result of dyads and triads. The present paper herein may provide an insight into the mechanisms of the formation of various intraspecific polyploids through sexual polyploidization inR. laetus.

Download Full-text

Impact of Structural Heterozygosity on Pollen Fertility and Chiasma Frequency in Leontopodium jacotianum from the Cold Deserts of Ladakh (Jammu and Kashmir), India

CYTOLOGIA ◽

10.1508/cytologia.84.251 ◽

2019 ◽

Vol 84 (3) ◽

pp. 251-254 ◽

Cited By ~ 1

Author(s):

Younas Rasheed Tantray ◽

Vijay Kumar Singhal ◽

Nissar Ahmad Khan ◽

Raghbir Chand Gupta

Keyword(s):

Chiasma Frequency ◽

Pollen Fertility ◽

Jammu And Kashmir ◽

Structural Heterozygosity

Download Full-text

Contemporary architectural production in the Alpine area through the lens of regionality

ARCHALP ◽

10.30682/aa1801introeng ◽

2018 ◽

pp. 11-13

Author(s):

Antonio De Rossi ◽

Roberto Dini ◽

Stefano Girodo

Keyword(s):

State Of The Art ◽

Central Core ◽

Scientific Committee ◽

Wide Angle ◽

Scientific Validity ◽

Architectural Production ◽

Alpine Regions ◽

Alpine Area ◽

Building Culture ◽

Alpine Space

Given that this is the inaugural edition, we thought that the first issue of the international journal «ArchAlp» needed to be characterized by a wide angle view, taking shape as sort of veritable tour d’horizon of the alpine space. Thinking with the scientific committee of the journal, it seemed to us that a reflection on the characteristics of contemporary architectural production in the European Alpine area, starting from regionally-based analyses and interpretations, could be very important. A description of the state of the art, which in order to have scientific validity must be based on comparative interpretations, has the aim of restoring continuity and differences in the “building culture” among the various Alpine regions. From here the idea of building the central core around a series of local monographs.

Download Full-text

Evoluzione della copertura vegetale in aree alpestri del Canton Ticino nel periodo 1971–2001 | Evolution of Vegetation Cover in the Alpine Regions of Canton Tessin: 1971–2001

Schweizerische Zeitschrift fur Forstwesen ◽

10.3188/szf.2004.0284 ◽

2004 ◽

Vol 155 (7) ◽

pp. 284-289 ◽

Cited By ~ 1

Author(s):

Pietro Stanga ◽

Niklaus Zbinden

Keyword(s):

Initial Conditions ◽

Ground Cover ◽

Climatic Conditions ◽

Human Pressure ◽

Aerial Photos ◽

Alpine Regions ◽

Subsequent Decrease ◽

Site Fertility ◽

Strong Expansion ◽

Evolution Of Vegetation

The retrospective study based on aerial photos (1971–2001) of the Canton Tessin made it possible to measure and analyze the evolution of the vegetation of eleven Alpine zones. The analysis shows a strong expansion of the arborescent vegetation and, at the same time, a decrease in other forms of ground cover (bush, shrub, meadow and unproductive spaces). Analysis of the data gives rise to the conjecture that the strong evolutionary dynamism evidenced by the areas under investigation is a result of the vast clearings carried out in past centuries to create pastures. Following the subsequent decrease in human pressure, nature today is attempting to rebalance the level of the biomass. These processes manifest themselves in different ways and with various intensity, depending on the interaction of numerous factors (e.g. climatic conditions, site fertility, initial conditions, evolution of anthropological pressure, etc.).

Download Full-text

Seasonal variation in chiasma frequency among three morphotypes of Eclipta alba

Chromosome Botany ◽

10.3199/iscb.5.33 ◽

2010 ◽

Vol 5 (2) ◽

pp. 33-36 ◽

Cited By ~ 2

Author(s):

Manjit Inder Singh Saggoo ◽

R. C. Gupta ◽

Ravneet Kaur

Keyword(s):

Seasonal Variation ◽

Chiasma Frequency ◽

Eclipta Alba

Download Full-text

Pollen Fertility of Some Simple and Compound Translocations of Cotton

Crop Science ◽

10.2135/cropsci1990.0011183x003000040041x ◽

1990 ◽

Vol 30 (4) ◽

pp. 952-955 ◽

Cited By ~ 2

Author(s):

David M. Stelly ◽

Kenneth C. Kautz ◽

William L. Rooney

Keyword(s):

Pollen Fertility

Download Full-text

Relicts from Glacial Times: The Ground Beetle Pterostichus adstrictus Eschscholtz, 1823 (Coleoptera: Carabidae) in the Austrian Alps

Insects ◽

10.3390/insects12010084 ◽

2021 ◽

Vol 12 (1) ◽

pp. 84

Author(s):

Wolfgang Paill ◽

Stephan Koblmüller ◽

Thomas Friess ◽

Barbara-Amina Gereben-Krenn ◽

Christian Mairhuber ◽

...

Keyword(s):

Ground Beetle ◽

Distribution Patterns ◽

Morphological Characters ◽

Molecular Data ◽

Ice Age ◽

Dispersal Ability ◽

Austrian Alps ◽

Alpine Regions ◽

Extant Species ◽

Limited Dispersal

The last ice age considerably influenced distribution patterns of extant species of plants and animals, with some of them now inhabiting disjunct areas in the subarctic/arctic and alpine regions. This arctic-alpine distribution is characteristic for many cold-adapted species with a limited dispersal ability and can be found in many invertebrate taxa, including ground beetles. The ground beetle Pterostichus adstrictus Eschscholtz, 1823 of the subgenus Bothriopterus was previously known to have a holarctic-circumpolar distribution, in Europe reaching its southern borders in Wales and southern Scandinavia. Here, we report the first findings of this species from the Austrian Ötztal Alps, representing also the southernmost edge of its currently known distribution, confirmed by the comparison of morphological characters to other Bothriopterus species and DNA barcoding data. Molecular data revealed a separation of the Austrian and Finish specimens with limited to no gene flow at all. Furthermore, we present the first data on habitat preference and seasonality of P. adstrictus in the Austrian Alps.

Download Full-text