Browsing by discipline "Växtproduktions biologi (trädgårdsvetenskap)"

Calendula officinalis is grown widely as an ornamental plant across Europe. It belongs to the large. Asteraceae family. In this study, the aim was to explore the possibilities to use Calendula officinalis as a new model organism for flower development and secondary mechanism studies in Asteraceae. Tissue culture of Calendula officinalis was established using nine different cultivars. Murashige & Skoog (MS) medium with four different combinations of plant growth regulators were tested. Of all these combinations, the medium containing 1mg/l BAP, 0.1 mg/l IAA, and 1mg/l Zeatin achieved highest frequency of adventitious shoot regeneration from hypocotyl and cotyledon explants. Virus-induced gene silencing is a recent developed genetic tool for charactering the gene functions in plants, and extends the range of host plants that are not accessible for Agrobacterium transformation. Here, tobacco rattle virus (TRV)-based VIGS technique was tested in calendula (cv. Single Orange). We used TRV carrying Gerbera hybrid phytoene desaturase (PDS) gene fragment to induce PDS silencing in calendula. Vacuum infiltration and syringe infiltration methods both resulted in photo-bleaching phenotypes in leaves, bracts and petals. Loss-of-function phenotypes occurred on calendula 13 days post-infiltration. In conclusion, the data indicates that calendula explants can be regenerated through tissue culture which is a prerequisite for development of stable transformation methods. However, further optimization is still needed to improve the frequency. In addition, VIGS was applied to silence PDS marker gene expression indicating that this method has potential for gene functional studies in future.

The special forms of conifers have been a matter of interest due to their ornamental values for centuries all over the world. Special forms have traditionally been reproduced by vegetative means, mostly by cuttings or grafting methods. At present, the vast majority of ornamental coni-fers traded in Finland is imported from abroad. The winter hardiness of foreign taxa is often in-adequate, causing wasted work and expenses when plants have to be replaced after cold winters. The aim of this thesis was to find suitable propagation methods for special forms of our native conifers and in that way enhance their domestic production. The plant material used in this study included special forms of native Norway spruce (Picea abies (L.) Karsten) and juniper (Juniperus communis L.), common Norway spruce and eight foreign conifer taxa. The methods studied were propagation by stem cuttings and by grafting. The aim of the grafting experiment was to compare the healing of graft union in different genotypes of Norway spruce. In the cutting experiment the effects of genotype, age of the mother plant, position of cutting and treatment with a growth regu-lator on the rooting of conifer cuttings were studied. All of the genotypes of Norway spruce studied were successfully grafted and formed a perfect graft union. For aesthetic reasons propagation by cuttings may still be more suitable for at least dwarf conifers. Genotype had a very significant effect on the rooting of coniferous cuttings. Cut-tings from a juvenile special form of Norway spruce rooted better than those taken from adult trees. Generally, the position of cutting did not significantly affect rooting of special forms of Norway spruce. In one colour form, however, cuttings obtained from the juvenile lower part of the stock tree rooted far better than cuttings taken from the top of the same tree. Treatment with in-dolebutyric acid had a negative effect on the rooting of Norway spruce and juniper, but no signifi-cant effect on the cuttings of foreign conifer taxa. Introducing special forms of native conifers would add to the diversity of home gardens and public parks in a sustainable way. To advance commercial production of native selections we need to pay regard to the rooting ability of the special forms, not only their appearance. It is cheaper to reproduce the special forms by cuttings than by grafting methods. Plants produced by cuttings also have more stable growth habit than grafts do, which is especially important for dwarf conifers.

Strawberry (Fragaria × ananassa Duch.) is both quantitative and economically most important cultivated berry in Finland. The problem in Finland is low crop yield and short harvest season. During the main season the high supply lower radically the price. The price is highest before and after the main season. Production with everbearing strawberries would give long and even harvest season with more stable price. Everbearing strawberries suit well for table-top production in polythene tunnels with drip irrigation and fertilization. Everbearing strawberries produce flowers and berries during the whole season which affects the nutrient demand. Three different electrical conductivities in the nutrient solution, 1,5 mS/cm, 2,3mS/cm and 3,0 mS/cm, with N:K –ratio 1:1,5 during the ripening, was investigated. The fourth electrical conductivity was 2,3 mS/cm with N:K –ratio 1:2 during the ripening. The vegetative growth, crop yield and quality was evaluated. The amount of drainage water was measures and the amounts of leached nitrogen and phosphorus was analysed. The varieties in the study were ‘Malling Opal’ and ‘Rondo’. Like in previous studies the nutrient demand of strawberry is relatively low. Strongest vegetative growth, highest yield and largest berries was observed with the lowest (1,5 mS/cm) nutrient level. The nutrient level had very little effect on the fruit quality or starting time of the harvest season. The change in the N:K -ratio during ripening did not affect the fruit quality. The uptake of water was highest in the nutrient solution with lowest electrical conductivity. The problem with the water uptake with high electrical conductivity was probably caused by the high ion content in the nutrient solution. The amounts of nitrogen and phosphorus increased significantly in the leaching water with increasing electrical conductivity in the nutrient slution.

The aim of this study was to compare warm white LED and High Pressure Sodium (HPS) -lamps in the greenhouse cultivation of lettuce. Two experiments were carried out in which lettuce growth and external quality was observed, the effect of lamps on leaf temperature was measured and the electricity consumption of LED- and HPS-lamps was compared. First experiment carried out with iceberg lettuce (´Frillice`) and second experiment with red oakleaf lettuce (´Rouxai´). In the second experiment, the effect of light treatment on the color of leaves was also investigated. The presence of tipburn was another measurement of external quality in both experiments. LED-lamp with DLC-sensor (Dynamic Light Control), which was designed to optimize the illumination according to the existing natural light, was also included in the experiments. Light quality or observed differences in temperatures or relative humidity did not significantly affect the fresh weight or external quality of ice berg lettuce. Oakleaf lettuces grown under LED-light were much smaller and they had more tipburn symptoms compared to HPS-treatment. No significant differences were found in the anthocyaninlevels of oakleaf lettuce grown under different lightning treatments. LED -lighting consumed about 22% less electricity than HPS-lamp in both experiments. However, energy efficiency of HPS- and LED-lamps cannot be directly compared, since HPS-lamps illuminated larger area than the LED- luminaires. DLCsensor was able to adjust illumination according to natural light and to reduce energy consumption, but it did not increase fresh weight accumulation in relation to power consumption compared to LED-luminaire without DLC.

The study was performed to clarify if women consumers´ objective and subjective knowledge and general attitudes to their attitude have effect, and if the attitude to the information desire about the genemodified crops (=GM-crops) has effect. The results could be utilised in the informing about the GM-crops. The about 13 000 members of Marttaliitto ry was chosen as a sample which represents Finnish women consumers. The material was collected as email survey and the female interviewees' answers that were used for analysis came altogether 2 241 pieces. In a multinomial logistic regression analysis the attitude towards the GM-crops (=the GM-attitude) as explanatory variables was obtained, subjective and objective information, general attitudes towards nature, plant breeding and organic food, and confidence to information about the GM-crops given by the journalists, researchers, the European Union and environment organisations. From demographic variables the age and the place of residence explained the GM-attitude. The information desire was explained by the GMattitude. The woman consumer's subjective and objective knowledge and the general attitudes towards nature, plant breeding and organic food affect an attitude towards the GM-crops and the attitude affects an information desire about the GM-crops. In the K-means cluster analysis it was formed based on the GM-attitude, four different women consumer segments: green opponents, green fighters, non-green supporters and acceptors. The green opponents and acceptors wanted to have information about the matter areas concerning GM-crops more than the non-green supporters and the green fighters from the segments. The results can be used as help for the communication when the women consumers informing of the matters which are related to the GM-crops. More information is wanted so there should be it easily available. To maximise the effectiveness of the communication, communication should be focused according to different consumer segments. In the future it would be interesting to know how women consumers will be reacted to the information about the GM-crops if there is information from the desired sources available. Would the women consumers use information and would they be interested in the information for real?

Suomen tärkein viljelty marja on mansikka, jonka tuotannon eräänä ongelmana on satokauden lyhyys. Eräänä ratkaisuna tähän saattaisivat olla jatkuvasatoiset mansikkalajikkeet, joita ei Suomessa ole laajassa viljelyssä lähinnä sopivien lajikkeiden puutteen vuoksi. Mansikalla vegetatiivinen ja generatiivinen kasvu kilpailevat osittain keskenään. Jatkuvasatoisilla mansikkalajikkeilla generatiivista kehitystä ja sadon muodostumista edistää pitkä päivänpituus. Satopotentiaalia voidaan lisätä myös kemiallisilla kasvun- sääteillä. Proheksadioni-kalsium (ProCa) toimii gibberelliini-inhibiittorina edistäen juurakon haaroittumista ja siten kukkimista sekä ehkäisten rönsyjen muodostumista. Satopotentiaalia lisää myös lyhyt päivänpituus edistämällä kasvin koon kasvua. Tehdyssä tutkimuksessa testattiin kolmen jatkuvasatoisen mansikkalajikkeen (Elan, Malling Pearl ja Tango) reagointia sekä lyhyeen (12 h) että pitkään päivään (18 h) ja ProCa:an (0 ja 200 ppm). Käsittelyt suoritettiin taimikasvatuksen aikana, minkä jälkeen kasvit siirrettiin hyötöön muovitunneliin. Kasvien vegetatiivista ja generatiivista kehitystä havainnoitiin sekä taimikasvatuksen että hyödön aikana useiden vasteiden, kuten lehtien, rönsyjen, juurakon haarojen, kukintojen ja marjojen määrien, avulla. Käsittelyillä oli vaikutusta sekä vegetatiiviseen että generatiiviseen kehitykseen, mutta erot koejäsenten välillä tasoittuivat melko nopeasti. Pitkä päivä nosti Elanin ja Malling Pearl:n kukkien määrää, mutta vain ProCa:lla käsitellyillä koejäsenillä. Tangolla kukkia sen sijaan kehittyi vain lyhyenpäivän koejäseniin, se käyttäytyi meidän oloissamme siis täysin lyhyenpäivänlajikkeen tavoin. Myös ProCa lisäsi kukintojen määrää, mutta lajikkeiden välillä esiintyi vaihtelua vaikutuksen voimakkuudessa. Sekä pitkä päivä että ProCa nostivat Elanin ja Malling Pearl:n satotasoa varsinkin alkukesästä, eli sadontuotto aikaistui. ProCa nosti myös Tangolla sekä aikaisen että kokonaissadon määrää. Tutkimus osoitti mahdollisuuden mansikan sadon aikaistamiseen ja sen määrän nostoon jatkuvasatoisten lajikkeiden avulla, jos niiden potentiaalia pystyttäisiin täysin hyödyntämään. Lisätutkimusta tarvitaan kuitenkin edelleen sopivien lajikkeiden ja viljelytekniikoiden kehittämiseksi.Strawberry is the most important cultivated berry in Finland but one of the problems of cultivation is shortness of the harvesting period. Everbearing strawberry cultivars could provide an alternative to extend the period. However, these are not yet broadly cultivated in Finland mainly due to the lack of suitable cultivars. The vegetative and generative growth of strawberry partly compete with each other. Generative growth and yield formation in everbearing strawberries is enhanced by long day length. Yield potential can also be increased by using chemical growth regulators, like prohexadione-calcium (ProCa). This inhibitor of gibberellin biosynthesis enhances crown branching and flowering, and prevents runner formation. Yield potential can also be thought to increase by short day length through increasing plant size. In this study, the effect of short (12 h) and long (18 h) day length as well as ProCa (0 and 200 ppm) on the growth of three everbearing strawberry cultivars (Elan, Malling Pearl and Tango) were tested. The treatments were carried out during plant propagation after which the plants were moved to a plastic tunnel for forcing. Vegetative and generative development of the plants were observed during both plant propagation and forcing by measuring several variables, such as number of leaves, runners, crown branches, flowers and berries. The treatments affected both vegetative and generative development. Long day increased the number of flowers on Elan and Malling Pearl, but only on ProCa treated plants. Flowering of Tango on the other hand was only induced in the short day length. Thus, in our conditions, it behaved as a short day cultivar. ProCa also increased the number of flowers, but there were some differences between the cultivars in the strength of the effect. Both long day length and ProCa increased the yield of Elan and Malling Pearl especially in the early summer, thus advancing the start of fruiting. ProCa also increased both early and total yield of Tango. This study showed the possibility of advancing and increasing strawberry yield through everbearing cultivars if their potential could be fully utilised. Further research is however necessary in order to develop suitable cultivars and cultivation methods for our growing conditions.

Identification of apple species (Malus Mill.) has traditionally depended on morphological descriptions. Cultivar identification based completely on characteristics is problematic at best as original descriptions are often lacking. Additionally authenticity of nursery products has been criticised in Finland since early 20th century. As DNA and molecular methods have developed, new ways of species and cultivar identification have emerged. Microsatellites have proven to be especially useful for identifying individual genotypes and for defining genetic polymorphism within a chosen population. Markers designed for apple (Malus × domestica Borkh.) function on all apple species making them extremely useful for Malus research. In our study, DNA fingerprinting was carried out with nine microsatellite markers copying 12 loci. Study material consisted of 201 samples representing 200 accessions. Most of the 99 study samples were from Finnish nurseries. Reference samples were gained from various botanical collections from North America and Europe. Altogether 47 study samples were re-identified or their original names authenticated. 52 samples remained nameless or unauthenticated. Two KESKAS cultivars were renamed as DNA-fingerprints revealed their true identity. Microsatellite fingerprinting proved to be a suitable method for ornamental crab apple cultivar authentication. False naming of nursery propagation material was evident and future studies are needed to illustrate the problem further.

Plant growth and morphology can be manipulated with light. Previously light manipulation experiments were mostly conducted by modifying the solar spectrum with light absorbing filters. Today, research can be conducted with modern LED lighting techniques, which enables specific spectrum tailoring. Light can be tailored specifically for a species or a family, and the needs of the farmer can also be taken into consideration. In this study, tomato (Solanum lycopersicum L. cv ’Efialto’) seedlings were grown under six different spectra. Plant morphology, stomatal function and drought tolerance were measured. Growth measurements included stem height, plant fresh and dry weight, leaf -area and leaf number. In addition, the effect of light quality on leaf morphology was studied by measuring leaf blade and petiole length. All measurements were conducted on well-watered and water-stressed plants, in order to study the effect of drought on vegetative growth and drought tolerance. Stomata conductance was studied by measuring leaf temperature prior to and during water stress. Leaf surface temperature indicates transpiration rate; thus the higher the conductance the lower leaf temperature. In addition to leaf temperature measurements, photosynthesis and stomatal conductance were measured by leaf level infra-red gas analysis. R:FR ratio was the dominant factor for affecting plant morphology. However, the B:G ratio also played a key role; when the B:G ratio was low, it further enhanced the elongation growth, a response caused by low R:FR ratio. Irradiance in green and yellow wavebands regulated stomatal closure. During water stress, the light treatment with the highest green irradiance, induced more rapid stomatal closure which was evident as increased leaf temperature and decreased gas exchange. Light-depenedent stomatal closure and decreased transpiration could explain the improved performance of these seedlings during the drought period. Light spectral quality thus affected the drought tolerance of tomato plants through its effects on plant morphology and stomata function.

The herbaceous vegetation of Viikinoja naturalistic rain garden in Viikinojanpuisto, Helsinki, was mapped about 10 years after construction. Viikinoja garden is a brooklike reworking of a part of an old main ditch and can be classified as an enhanced wetland. In the garden area, 28 species of herbaceous perennials were planted in 1999, 23 of them within the actual wetland area. The aim of the study was to evaluate the success of planted herbaceous perennials in the wetland area and to compare this data to the life history traits of these species. In addition, the spontaneous herbaceous vegetation in the area was surveyed and the success of some of these species was compared to their life history traits. Species' success was assessed by their proportional presence, general coverage and local coverage. Of the 23 species planted in the wetland area, 19 had survived and of these, ten can be called succesfull. Spontaneous species were identified from over 80 genera. The combined coverage of the planted species in the study area was 57 %, while that of spontaneous species exceeded 90 %. Both groups were dominated by graminoid species (Phragmites australis and other grasses, Typha latifolia, Scirpus sylvaticus and Carex species). Of the life history traits, competitiviness, maximum height and lateral spreading ability had a positive effect on species' success, especially with respect to perennials at their planting sites. Ruderality had a negative effect on the success of perennials. It was concluded that the vegetation of Viikinoja is entering competitor-dominated phase. Future long-term development depends largely on park management practices regarding mowing, dredging and cutting of willows.