Browsing by study line "Växtproduktionsvetenskap"

Plant hormones (phytohormones) are important substances that regulate physiological processes like fruit development in plants. Auxin, cytokinins and gibberellins are thought to be the most important phytohormones during fruit development. The aim of this work was to investigate whether auxin affects the temporal and spatial patterns of cytokinin during fruit development of woodland strawberry. Additionally, this work also examined the effect of auxin on the fruit development from morphological point of view. F. vesca plants transformed with TCSn:VENUS-H2B cytokinin reporter construct were used as plant material. Three different treatments were used: pollination, emasculation and auxin application after emasculation. Developmental stages S1-S5 and S9 (S1 at flower opening, S2 two days after that, further stages every third day except S9 22 days after flower opening) were observed. In the morphological analysis, the fruits (receptacles) were weighted and measured. The analysis of cytokinin pattern was done by observing the expression of VENUS fluorescent protein using confocal microscopy. The results showed that the treatments influenced fruit morphology. The emasculated receptacles had very minimal growth, pollinated grew into normal fruits and auxin treated developed similar to the pollinated. The distribution and amount of cytokinin differed between the treatments. The auxin treated and pollinated samples showed more cytokinin signal in the pith and cortex tissues than the emasculated samples. The vascular tissue showed clear cytokinin signal among all treatments in the earlier (S1-S3) stages. Conclusion was that exogenous auxin application impacts the cytokinin pattern within the receptacles in a manner similar to pollination. In addition, it was confirmed that auxin is needed for proper fruit development in woodland strawberry. In future, it would be interesting to study the effect of cytokinin on auxin, to gain more information about the interaction of these two phytohormones.

Biochars are produced from organic materials using pyrolysis and are used as a soil amendment to improve soil fertility and plant growth. Biochars are particularly beneficial to soils with high acidity, low carbon (C) content, nitrogen (N) content and other nutrient contents. However, it is not well-studied whether the beneficial effects of a biochar exist for the long-term. The aim of this study was to examine the effects of one-time application of spruce biochar on soil and barley (Hordeum vulgare L.) properties in the long-term. For this purpose, soil and plant properties were measured from the biochar field experiment in a boreal nutrient deficient Umbrisol where spruce biochar was applied eight years earlier. The experiment had a split-plot design with biochar application rates (0, 5, 10, 20 and 30 t ha-1) as the main-plot factor. The effects of fertilisers alone and their interaction with biochar were studied with three treatments (control, mineral fertiliser and meat bone meal (MBM)) as the sub-plot factor. Soil moisture content at 0–15 cm depth, as well as pH, plant available nutrients, total C and N content and C/N ratio of the soil were measured. Barley growth was assessed indirectly by measuring leaf chlorophyll content (SPAD), leaf area index (LAI), plant stand density, biomass, C and N content, C/N ratio, grain yield and weight of 1000 grains (TGW). No consistent significant effects of biochar on soil moisture content or soil chemical properties were observed. Biochar application did not have significant effects on leaf chlorophyll, leaf area index, plant density or biomass of barley. The highest biochar application rate of 30 t ha-1 tended to increase grain yield and TGW but the increases were not statistically significant. Mineral and MBM fertilisers produced similar grain yields although N was likely less available from MBM earlier in the growing season. Biochar and fertiliser interaction did not have significant effects on any of the measured properties. The lack of effects of biochar may be explained by the high amount of initial soil organic matter as well as low liming effect and low nutrient content of the used biochar. In addition, the lack of significant effects of biochar also suggests loss of biochar from topsoil due to weathering and downward displacement of biochar over the period of eight years. In this study, biochar application did not have negative consequences on the measured soil and crop properties. Therefore, it should be safe to use. Biochars may provide a viable option to sequester carbon in boreal agriculture. Further research on this is still needed to investigate the long-term effects of different types of biochars on different types of soils.

The high quality of seed is a basic requirement for producing high yields of good quality. The production conditions may vary and their effect to seed quality have not been fully understood. The aim of this study was to define how stress during growing season affects germinability of barley seeds and the yield potential of the next generation. The plants were exposed to different stress conditions in a greenhouse and in a pot test hall. The stress conditions included plant disease infection in different growing stages, low and high temperature in different growing stages, drought, water logging and early harvest. The germinability of the seeds was studied one, three, six and nine months after the harvest. The obtained results were inconsistend as for many stress treatments the germinability results of the samples varied between different measuring time points and were variously lower or higher compared to results of the control sample. The only stress condition that clearly lowered the germinability was early harvest. The second part of the work was to study the effect of stress conditions on the crop yield of the next generation. The seeds produced under stress conditions were grown in optimal conditions and thus it was studied whether the stress of the previous generation affects the crop formation of the next generation. No clear dependence was observed between the stress treatments of the previous generation and the yield performance of the next generation. As further research, it would be beneficial to study the effect of the stress conditions on vigour of the next generation seeds.

Indoor gardening is continuously increasing among consumers. Consumers and greenhouse entrepreneurs are looking for ways to optimize growing conditions for their plants to produce high quality and good yield. So far, the effects of LED lights on the plant biomass production and on the composition of volatile aroma compounds have been investigated. However, the effects of different lights on the taste and odor of homegrown herbs is yet to be discovered. The aim of this study was to investigate how different light conditions would affect the composition of compounds that are mainly responsible for the specific flavor of selected model plants. The main goal was to investigate what type of volatile compounds could be obtained in plants grown under different light conditions. The second goal was to investigate how non-volatile saliva soluble compounds could be modified due to the different growing conditions. Coriander and dill were selected as model plants. Coriander is globally utilized herb while dill is one of the most used herbs in the Nordic countries. Due to their strong flavor, both of these herbs divide consumer opinions and therefore investigation of their flavor modification is important. Coriander and dill were grown in domestic smart gardens manufactured by Plantui Oy. Used light conditions included control, green and blue light. Control light composed of a combination of blue, green and red light. Light source was LED lights. The herbs were grown at +22 °C and at humidity of 56.5 %. Used nutrients were ready-made mixtures by Plantui Oy. The composition of artificial saliva was optimized with commercial coriander and dill for the investigation of flavor compounds. Coriander and dill samples were extracted with the developed artificial saliva after which the volatile compounds were analyzed by a combination of gas chromatography and mass spectrometry (GC-MS) and non-volatile compounds by a combination of liquid chromatography and mass spectrometry (LC-MS). Principal component analysis (PCA) was utilized to investigate the composition of volatile compounds while partial least squares-discriminant analysis (PLS-DA) was used to investigate the differences in the non-volatile compounds. Used light conditions altered the chemical composition of herb leaves. Also, light conditions had a visible effect on plant growth. For example, herbs grown in blue light germinated weakly and produced less biomass. The profile of volatile compounds in corianders grown under green and blue light differed from those grown under control light. For dill, the profiles differed only for the samples grown under blue light. Majority of the volatile compounds were components of the essential oils of herbs and compounds that enhance stress tolerance. When looking at saliva soluble non-volatile compounds, coriander grown under blue light was different from the one grown under control light while for dill a difference was observed both under blue and green light. Based on the results, special light recipes can be developed to modify the flavor of coriander and dill. Further research is still needed, especially on the effects of light conditions in plant cell signaling and thereby on the morphological changes in plants and as a consequence on their flavor compounds.

Organic agriculture is growing steadily in Europe. Demand for organic products and pressure from policy changes in the EU have created a need for organic seed material. One of the limiting factors is the lack of organic variety testing. Currently no official organic Value of Cultivation and Use (VCU) trials or standards for organic variety testing excist in the EU. Plant breeding companies like Boreal Plant Breeding want to offer varieties for organic farmers but they lack information on the performance of their varieties in organic conditions. The main objective of this experiment was to determine the most important variety traits in organic agriculture in Finland and which of the Boreal Plant Breeding oat varieties exhibit the most favourable traits for organic growing conditions. Relationships between observed traits were also examined. A wide range of observations and measurements were performed from the trial throughout the growing season. Quality analysis of the yield were performed after harvest. The objects of examination during growing season included growth development, leaf area index (LAI), nutrient status with SPAD (Soil and Plant Analysis Development) measurements, plant height and yield components. Plant height and LAI appeared to be the best indicators for evaluation of performance potential of oat in organic conditions. SPAD value wasn’t found to have a connection to oat yield nor was it an indicator for oat LAI. High LAI increased oat height, yield and yield component shoots/m2 but effected negatively on the yield component panicles/m2 during the end of stem elongation. Plant height was a good indicator of yield level. The number of weeds and LAI value didn’t have a connection in this experiment and neither did weed number and yield. The early and late varieties varied in their reaction to the low-input growing conditions. Early varieties had generally lower yield but better yield quality than the late varieties. ‘Nella’ showed potential to be a variety with good yield quality and high yield in low-input conditions in Southern Finland. Area of cultivation and the end use of the oat are important factors in variety selection.