Research visit to the Netherlands to study aspects of Nerine production

Introduction and Background

September 2015 sees the start of my BSc Plant Science top up. Having completed the Foundation Degree earlier this year I was keen to move straight on to the top up year to achieve a full degree. I attended a lecture given by Ros Smith of the Rosewarne  Micropropagation Laboratory on how micropropagation techniques are used to conserve and multiply difficult to propagate species or those suffering with disease. I was fascinated with the subject and volunteered in the laboratory to learn more. I was able to get involved with a project working on old Nerine hybrids given to us by a UK breeder and collector, including Nerine ‘Hera’, ‘Aurora’ and ‘Fuchsine’. Hera and Aurora are recorded as being bred by Mr Rose of Oxford in the 1920s and were given an RHS award. These bulbs are virus infected, causing visible symptoms on leaves and a reduction in flowering ability for Hera and Aurora. We aim to micropropagate the material to generate virus-free plants, which may also improve flowering ability and make multiple virus-free plants. Working with a new species in micropropagation means a literature review and working out the best protocol to use. Due to the limited supply of material, we decided to develop the protocol on other bulbs before working on the Hera and Aurora. A simple multiplication protocol for bulb material has been developed, although there is still room for improvement. One of the Hera bulbs was used and five new plants have been created to work with, which are in the process of being further multiplied. As this material is still limited, other processes are being tested on Nerine material that we have plenty of. As a high level of fungal ontamination was encountered while using the bulb material to generate new plants; we decided to test ways to reduce it. My second year research project tested the antifungal activity of two antibiotics used in plant tissue culture. One reduced fungal contamination by approximately 30% in comparison to the control but due to potential negative side effects of antibiotics in culture (phytotoxicity, genetic change and resistance), I decided not to use this as standard practice and have been testing an alternative surface sterilant. Milton sterilising tablets offer an alternative to sodium hypochlorite (bleach) solution used as a standard surface sterilant. Preliminary tests show plant material can cope with multiple treatments at different growth stages and exhibit improved recovery in comparison to bleach.
Removing virus through meristem culture is a procedure often used in micropropagation; however it is not always successful or straightforward. The active growing point of cells is excised and initiated into culture. This growing point can be 0.5 – 1.5 mm across and needs to be dissected out using a microscope, tweezers, scalpel and a needle. Aseptic conditions and the correct care regime are required to ensure
growth. The potential of virus-free material from the meristematic growing point is inversely proportional to its size but the likelihood of anything generating from it is positively proportional to the size. So, the smaller the meristem, the more chance there is that the resulting plants will be virus-free. However, the smaller the meristem, the more difficult it is to grow on. I tried a number of meristem excisions and two types of growing media, using a technique that we had used successfully with rhubarb of putting meristems onto filter paper bridges with the bases sitting in nutrient liquid. This did not work for any meristems and I did not find further specific details on the care regime for meristems of this species within the literature.