Browsing by study line "Växtproduktionsvetenskaper"

Tomatoes (Solanum lycopersicum) are one of the most important food crops in the world. Long supply chains force producers to harvest the fruit before ripening. Ripening then happens in super markets or at the end–consumer. Partly due to the early harvest, tomatoes are perceived flavorless, especially in the wintertime. In addition to a demand for more flavorful produce, consumers are also increasingly interested in healthy food and are looking at the nutritional value of their food before the price tag. As tomatoes are a major crop, they could potentially also contribute to the daily nutrient intake of consumers, such as lycopene, which is i.e. suggested to have preventative qualities towards cancer. Several studies have been conducted to find out how light emitting diodes (LED –lights) could influence the plant and its compounds during growth, but post-harvest research to a lesser extent. Research on post-harvest LED–lighting suggests that quality attributes could also be influenced post-harvest. Important parameters to look at are color and firmness, as they are what buying decisions are primarily based on. Further, lycopene, but also total soluble sugars (TSS) and titratable acidity (TA), and especially their ratio, which defines how tomato flavor is perceived, are worth studying. Therefore, this study aimed to find out, how LED–light treatments could be used to steer the post-harvest quality of tomatoes. Three continuous light treatments were used; Blue, far-red, a standard growing light with high red to far-red ratio and dark as control. The study was done on two cultivars by measuring TSS, TA, lycopene, vitamin C and firmness of the tomatoes every fourth day for 12 and 15 days. Additionally, a set of tomatoes was analyzed for changes in weight and color. The results suggest that LED-lights do influence the quality characteristics of tomato fruit. Blue light seemed to decrease firmness, but to increase lycopene. Lycopene accumulation was also enhanced by a high red to far-red ratio, whereas far-red had a reversing effect. Both blue and high red to far-red ratio treatments increased the chroma values, making the tomatoes brighter in color. Far-red seemed to enhance red color development and to retain firmness, but to decrease lycopene accumulation and to make the color duller. Tomatoes kept in the dark had low lycopene content and a dull coloration. Results on TSS and TA indicate differences in genotype responses, which further underlines the need for further research on the topic and especially the effect of cultivar. The results of the study indicate that tomatoes should not be kept in the dark during storage, as then the full potential of their external and internal quality will not be reached. High red:far-red ratio lighting increases lycopene and brightens the coloration, and could be considered to be used during storage. However, other external factors affecting quality, such as ethylene and temperature, should be included in the future research to study their effect and correlation with light in regard to tomato fruit quality.

Secondary metabolites are bioactive compounds that help the plant to adapt in different adverse environmental conditions but are not an essential part of plant developmental processes and also secondary metabolites have pharmaceutical value because of their antioxidant, anticancer, antibacterial and antifungal properties. Type-III polyketide synthases (PKSs) are a group of polyketide synthases that produce secondary metabolites with diverse biological activities in plants. The main objective was to localize the PKSs G2PS1, G2PS2, FvCHS2-1, HlVPS into the peroxisomes for synthesizing secondary metabolites in plants. The experiment was performed by amplifying the genes with specific Px-targeting signal. Then the genes cloned into destination vector pEAQ-HT-DEST1. The plasmid constructs were transformed to Agrobacterium tumefaciens and agro-infiltrated to Nicotiana benthamiana and Petunia hybrida leaf tissue. Western blotting results revealed that all proteins were expressed in infiltrated leaves of both tobacco and petunia but HPLC chromatograms showed that only the protein FvCHS2-1 produced novel peaks for metabolites in tobacco.

Paineistettu kuumavesiuutto on menetelmä, jossa rahkasammaleesta saadaan uutettua arvokkaita ainesosia veteen ympäristöystävällisesti. Rahkasammaleesta uutetulle nesteelle on olemassa monia jatkojalostusmahdollisuuksia esimerkiksi erilaisten kemikaalien raaka-aineena. Rahkasammaleen uuttoprosessissa syntyy uuton läpikäynyttä rahkasammalmateriaalia, jolle olisi taloudellisesti kannattavaa löytää jatkokäyttöä, mikäli rahkasammaleen uuttoa harjoitettaisiin teollisessa mittakaavassa. Kokeessa tutkittiin uuttoprosessin läpikäyneen rahkasammaleen sopivuutta kasvien kasvualustamateriaaliksi. Uutettua rahkasammalta sekoitettiin käsittelemättömään rahkasammaleeseen 100:0, 75:25, 50:50, 25:75 ja 0:100 kuivapainon suhteessa ja niiden vedenpidätyskykyä, sähkönjohtokykyä ja pH:ta seurattiin kasvihuonekokeessa. Kontrollikäsittelynä toimi turve. Lisäksi seurattiin kasvualustan vaikutusta basilikan taimettumiseen, pituuskasvuun, lehtien lukumäärään sekä kuiva- ja tuorepainon kertymiseen. Viljelyn aikana seurattiin myös mahdollisten kasvua inhiboivien yhdisteiden poistumista kasvualustoista, kun niitä huuhdeltiin neljä kertaa laimealla lannoiteliuoksella. Jatkokokeessa seurattiin uutetun rahkasammaleen vaikutusta yksi-, kaksi- ja monisirkkaisten testikasvilajien taimettumiseen ja tuorepainon kertymiseen. Uutettu rahkasammal ei sopinut basilikan kasvualustaksi tai sen osaksi, sillä siinä kasvaneiden kasvien kasvu oli erittäin heikkoa. Sen sijaan käsittelemättömässä rahkasammaleessa basilika kasvoi yhtä hyvin kuin turpeessa. Uutetun sammaleen vedenpidätyskyky oli selvästi matalampi kuin käsittelemättömän rahkasammaleen. Jatkokokeessa yksi- ja kaksisirkkaisilla testikasvilajeilla parhaan tuorepainon tuotti käsittelemätön rahkasammalalusta, ja 25 % uutettua rahkasammalta sisältävä alusta tuotti paremman kasvun kuin turve ja 50 % tai enemmän uutettua rahkasammalta sisältäneet alustat. Monisirkkaisten kasvien kasvu ei heikentynyt, vaikka kasvualustassa oli 25 % uutettua sammalta. Useimpien kasvilajien taimettuminen oli heikompaa ja hitaampaa 100 % ja 75 % uutettua sammalta sisältäneillä kasvualustoilla kuin käsittelemättömässä rahkasammaleessa ja 25 % uutettua sammalta sisältäneessä kasvualustassa. Uutetun rahkasammaleen kasvua inhiboiva vaikutus ei täysin selity sen fysikaalisilla ominaisuuksilla, kuten esimerkiksi heikolla vedenpidätyskyvyllä. Uuttoprosessin aikana on saattanut syntyä jokin kasvua inhiboiva yhdiste, jonka pitoisuus alustassa ei vähentynyt riittävästi, vaikka uutettua sammalta sekoitettiin käsittelemättömään rahkasammaleeseen.

The american cranberry (Vaccinium macrocarpon) is a woody perennial plant. Cranberry fruit has been studied for its many different health benefits due to the high level of human health-promoting compounds such as flavonoids and anthocyanins. The growing season is too short in Finland, and the fruits must be harvested before frost. Studies have shown that post-harvest lighting can affect the quality of fruits. Light treatment increases the anthocyanins content and red color in fruits. Lighting during storage might improve also shelf life. The aim was to find out how different light treatments affect different quality characteristics of fruits. In this thesis, the effect of three different light treatments on the accumulation of anthocyanins and phenols during 14 days following harvest in american cranberry fruits was investigated. The light treatment was APL (multispectrum), blue and red light. The control was dark treatment. In addition, the color of the fruits, the sugar content and titratable acids were measured. Light treatments increased anthocyanin content in all varieties compared to dark control. The most effective was APL treatment. The phenol content first (7 days) increased in all varieties, after which the increase continued only in Early Black and Howes varieties. There were statistically significant differences between the light treatments only for these varieties, but only 14 days after the treatments. The treatment did not have significant effect on sugar content or the titratable acids. The berries turned red in light treatments and the color intensity increased. The treatments differed significantly from the dark, but not with each other. The results of this thesis indicate that it would be possible to ripen cranberry fruits during storage. The berries could be harvested half ripe and ripened during storage using lights. There would also be a demand for domestic cranberries in the food industry, allowing imported cranberries to be replaced by a domestic alternative.

Cropping conditions are changing also at northern areas due the climate change. Extreme weather conditions demand more buffering capability from the soil and adjusting ability from the plants. Crop rotation and tillage system are in essential role while the change proceeds, as they effect to productivity, pest control and soil health. This study studied the effects of crop rotation on spring barley (Hordeum vulgare L.) yield and pests in two tillage methods, plowing and no-till. This long term (2005-2019) field experiment was arranged in Jokionen, southern Finland. In the experiment, there were two cropping systems: barley monoculture and five years crop rotation (pea – spring wheat – oats – turnip rape/rapeseed – spring barley). Both cropping systems were carried out in ploughed and no-till environment. This study examined the years 2009, 2014 and 2019, when the whole experimental area was on spring barley. In our study, crop rotation did not have considerable effect on barley yield, but tillage method had. Yields were bigger in the ploughed system than in the no-till system. Crop rotation reduced weeds in the plowing system and increased them on no-till. Crop rotation reduced the stem and root rot diseases in spring barley. Tillage method and crop rotation had also effect on leaf blotch severity, especially on scald (Rhynchosporium commune). Only a few insect violations appeared during the examination years, so the effects of crop rotation on occurrence of insects could not be evaluated. Long term crop rotation experiments give valuable information about the strengths and weaknesses of different rotations. Role of the diverse crop rotation will increase further in Finland. More attention needs to be paid to interaction between crops and tillage systems, avoiding soil compaction, focusing to improve soil health and structure so the plants would have good opportunities to use their whole yield potential.