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6 Uppsatser om Dormancy - Sida 1 av 1

The effect of cold stratification on germination in 28 cultural relict plant species : with the purpose of establishing germination protocols

Cultural relict plant species from the Nordic countries have been collected by the Nordic Genetic Resource Center (NordGen) for the purpose of conservation. To ensure high seed vitality in store, regular germination tests need to be conducted. It is important to get a correct viability status, but the knowledge of seed Dormancy in the cultural relict plants is often poor. The objective of this study was to investigate how seed Dormancy is affected by cold stratification. The study includes 31 accessions from 28 species with the purpose of establishing germination protocols.

Ljusets betydelse för rotknoppars groningsvillighet i åkermolke (Sonchus arvensis L.)

This study is about how changed light conditions induce Dormancy in plants. It is divided in two parts. First a literature study where quantification of light, the concept Dormancy, photoperiod and light quality are discussed. Second an experimental part, where the importance of light for sprouting capacity in root buds of perennial sow thistle (Sonchus arvensis L.) is investigated.In the science in how flowering in plants are induced the concepts short day/long day plants and light dominant/dark dominant are well-established. These concepts can also be applied to how light induce Dormancy in plants.

Rotningsstimulerande effekt och kemisk analys av vattenbaserad extraktion av vedartade och örtartade skott av Salix smithiana Willd. :

Cuttings of Lonicera xylosteum L. were treated with willow extract to study the response in rooting capacity. The extracts were prepared by mixing chopped pieces of Salix x smithiana Willd. with water in a warring blender. The investigation comprised 2 types of salix extracts based on differences and dynamics between twigs in winter Dormancy and twigs with new shoots. To explore the rooting response, three tests were made.

Reproductive physiology of the female cat

The cat is one of our most common pets. Understanding the reproductive physiology of the queen is important, not only for the knowledge of our domestic cats but also for wild undomesticated feline species, many of which have been reported endangered. Understanding the mechanisms behind the estrous cycle, ovulation and pregnancy is also important for handling the feral cat populations that are a problem in several countries. The purpose of this literature study is to look into the hormonal patterns of the reproductive physiology of the female cat, with focus on ovulation, pregnancy and pseudo-pregnancy, and from this information determine in which fields more research would be needed. The female cat is seasonally polyestrous in Sweden, meaning that she can have several estrous cycles during the breeding season but goes through a long period of reproductive Dormancy during the darker months of the year. The queen is considered an induced ovulator, with copulation triggering the release of luteinizing hormone (LH) from the pituitary gland needed for ovulation.

Blå vägens glasbjörkar : från groning till allé

Det här projektet består av en litteraturstudie på trädformig björk (Betula) i Sverige, samt en studie av glasbjörk (B. pubescens) längs en klimatgradient genom Norra Sverige och Norge. Längs den studerade gradienten skiljer sig vegetationsperiodens längd med över en månad i den kallaste delen av gradienten jämfört med den varmaste. Frön längs gradienten har studerats med avseende på grobarhet före och efter simulerad invintring i syfte att undersöka om det finns trender i grad av frövila och grobarhet längs gradienten. Den simulerade invintringen hade en positiv effekt både på groningshastighet och på andel frön som grodde.

Renkavlens biologi - möjligheter till kontroll

Renkavle har under lång tid varit ett stort problem för lantbrukare i stora delar av norra Europa och har etablerat sig på större arealer även i Sverige. Genom sin bio-logi är renkavle mycket väl anpassad till odling av höstsådd spannmål, speciellt i kombination med reducerad jordbearbetning. Det finns en ökande trend av både höstsådd spannmål och reducerad jordbearbetning som talar för att problemen med renkavle kommer att öka framöver. Även den pågående klimatförändringen mot ett varmare klimat i Sverige förbättrar förutsättningarna för att renkavle ska etablera sig längre norrut. Renkavle är ett ogräs som kräver en mycket hög grad av kontroll för att inte öka kommande år eftersom fröproduktionen hos renkavle kan vara mycket stor.