SAPS Student Sheet 11 - Wild Oats on the Move The Wild Oats awn (hair) is hygroscopic and moves rapidly (within a minute) in response to small changes in humidity. The Student Sheet shows one way of anchoring the seed and exposing it to different conditions so that movements of the awn can be observed and measured.
There are good opportunities here for investigations. Careful control of independent variables such as temperature as well as humidity will be needed, and there is great scope for identifying and measuring the dependent variable e.g. with a protractor and a stop watch. Once they have carried out steps 1 to 6, students could be encouraged to study the behaviour of the seeds when they are not anchored in blutack and to,try and relate this to the question of why the awn behaves as it does. Careful study of the seeds will reveal that the twisting and untwisting of the awn, combined with the spirally arranged, barb-like hairs at the other end of the seed provide a mechanism which will disperse the seeds and/or bury them in crevices.