Physiological and Genetic Aspects of Estonian Saw-Wort (Saussurea Esthonica)Conservation

ANOTĀCIJA Darba mērķis bija veikt kompleksu pētījumu par Igaunijas rūgtlapes (Saussurea esthonica Baer ex Rupr.) bioloģiju, kas ietver in vitro kultūru, fizioloģiju, reprodukciju, ģenētisko izpēti, tā rezultātā iegūstot izpratni par aizsargājamo sugu saglabāšanai nepieciešamo bioloģiskās informācijas apjomu un izmantojamām pieejām. Lai netraucētu dabīgo populāciju, reto sugu izpētei svarīgi lietot nedestruktīvās analīzes metodes. Dabiskos apstākļos pētīta vides ietekme uz fotosintēzi raksturojošajiem parametriem, kontrolētos apstākļos analizēta substrāta sastāva un mitruma ietekme. Analizētas in vitro metožu lietošanas iespējas saglabāšanai un sugas reprodukcijas spēja. Lai prognozētu sugas spēju pielāgoties mainīgiem vides apstākļiem un līdz ar to izdzīvot ilglaicīgi, pētīta ģenētiskā daudzveidība starp Latvijas populācijām, populācijām Latvijā un Igaunijā, kā arī Igaunijas rūgtlape salīdzināta ar astoņām citām Saussurea sugām izmantojot molekulāros marķierus. Atslēgas vārdi: Saussurea, in vitro, ģenētiskā daudzveidība, hlorofila fluorescence, reprodukcijaANOTATION The aim of the research was to undertake a comprehensive study on the biology of Estonian saw-wort (Saussurea esthonica Baer ex Rupr.) in order to obtain biological information and to elucidate approaches for conservation of this endangered species. The research examined in vitro culture, physiology, reproduction and genetic analyses. It is important to use nondestructive methods of analysis for investigation of rare plant species. The research on the influence of environmental factors, mineral nutrition and soil moisture on photosynthesis related parameters was performed. Possibilities for in vitro conservation in this species was examined as well as reproduction potential. Genetic diversity among and within populations in Latvia and Estonia was estimated. Investigation of the phylogenetic relationship of S. esthonica with eight other Saussurea species utilising two different molecular marker techniques was performed. Key words: Saussurea, in vitro, genetic diversity, chlorophyll fluorescence, reproductio

Variability of Seed Germination and Dormancy Characteristics and Genetic Analysis of Latvian Avena fatua Populations

Avena fatua is an economically detrimental weed found in cereal growing areas worldwide. Knowledge about the variation of dormancy and germination characteristics, as well as of the genetic diversity and structure can provide additional information about different populations within a region. Identification and development of potential indicators or markers of seed germination behavior, would be useful for modelling emergence and seed bank dynamics. This study aimed to describe the initial germination, dormancy, and morphological characteristics of seeds from different Latvian populations of A. fatua and to investigate the genetic structure of local populations. Seed samples from 26 to 41 locations in different regions of Latvia were collected over three years. Seed morphology, initial germination, and the effect of dormancy-breaking treatments were determined. Seeds from 18 Latvian populations with contrasting seed dormancy characteristics were genotyped. Although morphological differences between seeds from different regions were revealed, genetic analysis of the selected populations indicated that the population structure was not related to geographical location, which probably reflects the impact of anthropogenic dispersal of A. fatua seeds. The effect of dormancy-breaking treatments varied between years, between climatic zones and between populations, indicating environmental influences as well as inherited dormancy