9 November: Henrik Lütken

Three biotechnological methods to develop compact ornamentals

Henrik Lütken, Ph.D, Associate Professor

Department of Plant and Environmental Sciences, Copenhagen University


Plant height is a quality parameter of primary importance in a large number of economically important ornamental plants. Consumers prefer short, compact plants with good keeping quality and ornamental value. In addition, compact plants tolerate mechanical handling and transport far better than more elongated plants. Furthermore, smaller plants require less space in expensive production facilities, are easier to handle, have reduced transportation costs and advantages for retailers. Thus, compact plants are preferred throughout the whole production and postharvest chain increasing profit in production and distribution. Currently, the feature compactness is obtained through the extensive utilization of chemical growth retardation targeting gibberellin (GA) response, e.g. chlormequat, daminozide or paclobutrazol. The number of approved growth retardation compounds is highly dependent on the country of production. For example, application of paclobutrazol and daminozide is no longer approved in many European countries. In my talk I’ll present and discuss three biotechnological methods; a non-GMO, a cisgenic and a GMO approach to develop compact ornamentals exemplified by Kalanchoë. In the non-GMO method unmodified strains of the soil-born bacterium Agrobacterium rhizogenes are used for transformations and this method is not considered as a GMO method in the European Union and Japan. Using this method compact plants are produced by the insertion of T-DNA containing root loci (rol) genes from A. rhizogenes into potted plants. Infection of plants by A. rhizogenes induces the growth of hairy-roots at the infection sites due to the insertion of four rol-genes, rolA, rolB, rolC and rolD. In many ornamental plants, rol-genes have been successfully used, causing reduced plant height, short internodes and reduced apical dominance. The cisgenic approach involves KNOX (KN) homeotic proteins that generally are involved in stem meristem differentiation. These genes can be used to modify plant architecture by both overexpression and silencing. The compact plants derived from this method often show a higher degree of branching and darker green colour due to elevated chlorophyll content. The latter is a highly desired feature in the ornamental plant industry. In the GMO approach the Short Internodes (SHI) gene from the model plant Arabidopsis thaliana is ectopically expressed. The SHI gene encodes a transcription factor belonging to the SHI–gene family, where the members act by gene dose-effect and are partially redundant. Overexpression of the genes leads to compact plants with a phenotype of mutants defective in GA biosynthesis and response. Although flowering can be delayed it can be restored by application of minute amounts of GA. When expressed in ornamentals compact inflorescences were in particular observed.

26 October: Satu Ramula

A demographic approach for plant invasions

Dr. Satu Ramula

Biodiversity Unit, Lund University, Sweden 

 

Invaders generally show better individual performance than non-invaders and therefore, species traits could potentially be used to predict species invasiveness outside their native range. However, comparative studies have usually correlated traits with the invasiveness status of species, while few studies have investigated traits explicitly in relation to population performance in terms of the long-term population growth rate. Using data on multiple populations of an invasive herb in its invaded range, I demonstrate that the measures of a single or a few plant traits do not necessarily reflect population performance and invasiveness correctly because only some fitness-related plant traits map directly into the long-term population growth rate. Therefore, a demographic approach that takes the whole life-cycle into account is required. I illustrate that this demographic approach provides a tool for identification of the demographic processes with the greatest impact on population growth rates, enabling a better understanding of the population dynamics and potential management strategies for invasive plant species.

12 October: Gaia Luziatelli

 
The hidden treasures of the Andes: future possibilities for the promotion of under-utilized Andean root and tuber crops in Bolivia.

Gaia Luziatelli, PhD student

Department of Plant and Environmental Sciences, Copenhagen University

In the Andean Region of Bolivia farmers cultivate more than 4,000 landraces of native potatoes, however, the majority of them never reach the market. This situation is shared also by other Andean root and tuber crops which, despite the high nutritional values, medicinal properties and low input requirements, are being substituted by other non-indigenous crops. Solutions for making Andean Roots and Tubers Crops (ARTCs) more profitable for the farmers and better accepted by the urban population might be offered by gourmet restaurants and organic markets.

In my research I use a combination of ethno-botanical methods, market studies and agronomic field trials. The first two approaches serve to understand the problems faced by the farmers in the cultivation and commercialization of ARTCs, as well as how to meet the requirements of gourmet restaurants and organic markets. The field trials assess different organic treatments on native potatoes in the region of Colomi, in the Cochabamba Department.

The results of the study will hopefully contribute to the sustainable production of Andean roots and tuber crops in Bolivia, combined with the promotion of local and international markets.