Oilseed rape modified with pea lectin: insect pests, beneficial insects, plant competition and the attitudes of farmers
Anna Lehrman
Doctoral thesis from SLU.
Email: Anna.Lehrman@ekol.slu.se
Plants genetically modified for insect resistance have to be tested and compared to their non-GM counterparts with respect to their effectiveness against the insect pest, negative effects on other organisms and the other changes that modification may give rise to in the ecology of the plants.
Oilseed rape is one of our most prominent oilseed crops, but it is also a crop that is intensively treated against insect pests, chiefly the pollen beetle. In the project, an evaluation was made of rapeseed lines transformed with a protein, lectin from pea seed, which through a pollen specific promoter is only expressed in the anthers and pollen.
The transgenic plants had no effect on the adult pollen beetles, but caused higher larval mortality compared with non-transgenic plants. This indicates that the transgenic oilseed rape is not directly protected from the insect pest, but, if the effect persists under natural conditions, it could, together with the natural enemies of the pollen beetle, limit population growth.
The transgenic plants were also tested to find whether modification increased competitive ability, which would result in increased dispersion of the rapeseed plant outside the field and/or that crossing into wild relatives would result in invasive populations. The transgenic plants hade no competitive advantage compared with plants without pea lectin.
Transgenic oilseed rape was found to have a higher yield when grown together with plants without lectin than when grown in monoculture, while the opposite applied for non-transgenic oilseed rape. This is probably due to deterioration in pollen quality in the transgenic oilseed rape. Since lectin is only expressed in the pollen, it is primarily other insects, e.g. the honey bee which feeds on the pollen, that are exposed. The study showed, however, that bee larvae were unaffected by the transgenic pollen.
A survey was finally made to find what Swedish farmers think are the benefits and drawbacks of growing a crop modified for insect resistance. The majority were negative to GM crops and considered that the negative attitude of the consumers was one of the main drawbacks. They saw a higher yield as the potentially greatest benefit from growing a crop modified for insect resistance.
The role of zinc transporters in the absorption, translocation and storage of cadmium in wheat
Stephen Burleigh (project leader)
Summary of results with list of publications from Department of Ecology, Lund University.
Email: S_Burleigh@yahoo.com
Cadmium (Cd) is considered to be the heavy metal that poses the greatest risk to human health. In Sweden grain is the most important source of cadmium in the diet. There are however great differences between varieties of grain with respect to the amount of cadmium that they can accumulate. Some transporters for zinc (Zn) play an important part for the Cd uptake of plants.
The aim of this project is to enhance understanding of the factors which govern uptake and distribution of cadmium and to begin modifying these in order to reduce the content of heavy metals in our food. One family of Zn transporters which may have a great role in Cd transport in durum wheat has been identified. This research is a start towards full characterisation of the gene family. Knowledge of the genes that participate in the transport of Cd in the plant can be instrumental in developing durum varieties which store less Cd and can also provide knowledge of how distribution can be affected by external factors.
Germination and early growth of annual weeds
Per Millberg (project leader)
Summary of results with list of publications from IFM Ecology, Linköping University.
Email: permi@ifm.liu.se
In crop production without herbicides, knowledge is needed of the germination and early growth of annual weed species. In the project, we studied how the propensity to germinate varies and what it is that governs these variations. It is chiefly germination inhibiting mechanisms, predictability and the timing of germination that were evaluated, and also to what extent different germination properties are phylogenetically conservative or not.
The project has produced specific knowledge of germination requirements, dormancy and the environmental factors which strengthen and weaken dormancy. This knowledge can be used in predicting germination and can be of assistance in planning and prioritising weed control. The project has also produced a new model for comparisons of germination characteristics among populations, genera and species.
Mosses as a component on green roofs: establishment, specific technical properties and diversity
Nils Cronberg (project leader)
Parts of the results have been published in the scientific journal Science. Summary of results from Department of Ecology, Lund University.
Email: Nils.Cronberg@ekol.lu.se
Extensive green roofs with moss/Sedum cultures have attracted attention as a possible means of increasing green spaces in the urban environment. In previous research priority was given to vascular plants, while mosses were regarded less interesting and even a problem. The fact that mosses and vascular plants function in completely different ways was overlooked. Mosses have no roots but instead take up water over their entire surface. Because of this, water is rapidly taken up during rain and is lost even more rapidly in dry conditions. In comparison, mosses have a low nutrient requirement and a very good capacity to take up the substances present in rain and dry deposition (dust), including heavy metals and other pollutants. Mosses manage to photosynthesise at low temperatures in the autumn, winter and spring and are therefore green all round the year. One of the primary goals of this project has therefore been to investigate experimentally how biological differences between vascular plants and mosses influence technical properties and long term development.
The investigations confirm the picture that mosses perform an important function as a complement to vascular plants as components on green roofs. Mosses account for a large proportion of the short term water turnover on the roof. Potentially, this has great significance for the local urban climate. In the long term, the rate of decomposition appears to be comparable between mosses and white stonecrop, but the mosses have a good capacity to take up heavy metals and other compounds from rain and dust particles. The results also show that mosses have a propensity to absorb microparticles from the air. These are considered to be one of the most serious air quality problems in the towns of today.
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