THE POLLEN TUBE - AN IDEAL MODEL SYSTEM TO STUDY NON STATOCYTE PLANT CELL RESPONSE TO GRAVITY

摘要

Future space missions and implementation of permanent bases on Moon and Mars will greatly depend on the availability of ambient air and sustainable food supply. Therefore, understanding the effects of micro-gravity on plant reproduction is vital for future extra-terrestrial human existence. Numerous studies have demonstrated the effect of gravity acceleration or its absence on plant development in general and on statocyte cells in particular, but information on the behaviour of non-statocyte cells to a gravity change is scant. One of the main reasons is the long response time of the metabolism of non-statocyte plant cells to environmental changes. One of the constraints during a space mission, or, in particular, during sounding rocket flights, is experimentation time; therefore using a model system that is able to respond within few seconds or minutes to environmental changes is crucial. The fastest growing cell in the plant kingdom is the pollen tube, a tip growing cellular protuberance formed by the pollen grain that is responsible for fertilization, and consequently for seed set and fruit formation in higher plants. Even in in vitro conditions the pollen tube grows at speeds up to several micrometers per minute and it responds instantly and visibly to environmental changes. This rapid response makes it an optimal model system to study the effects of gravity changes on plant cell metabolism in short term experiments.