Investigate the Effect of Moisture Content on Wheat Grain Seeds Respiration Rate :: GCSE Biology A2 A-Level Coursework

Investigate the Effect of Moisture Content on wheat Grain Seeds Respiration RateHYPOTHESIS There allow for be a positive correlation between moisturecontent of wheat grains and their airing rate. Therefore as themoisture content (independent variable) increases so go forth therespiration rate (dependent variable).The rationale behind the hypothesis came from studying photosynthesisin plants. During the light-dependent reactions of photosynthesis, thephotolysis of water (H2O) occurs inner photosystem II. The productsof photolysis combine with NADP from photosystem I, to form reducedNADP. This reduced NADP passes to the light-independent reactions ofphotosynthesis, where it is utilised to make triose phosphate fromglycerate 3 phosphate. Without water, photolysis would not occur andtherefore the light-dependent and light-independent reactions wouldnot make out place at all. Therefore I would predict that the highermoisture content of wheat grain seeds the higher the respiration ra tewill be, this is because the seeds will be able to utilise more waterthan a wheat grain seed with low moisture content.VARIABLES The independent variable used in this sample is goingto be moisture content, and the dependent variable will be therespiration rate. The other variables temperature, air pressure andair will be kept at fairly constant levels. Carrying out theexperiment inside a fume cupboard will help achieve in charge thesevariables to remain constant. However another variable sunlight cannotbe controlled during this experiment, and will obviously vary duringthe experiment. The possibility of using a standard light electric-light bulb to keeplight levels constant was considered, but was rejected due to safetyfears e.g. overheating when the experiment was not being monitoredduring the time between readings.BACKGROUNG KNOWLEDGE harm of stored grain seeds is animportant economic problem in agriculture, therefore it is importantto find out the most suitable conditions f or stored grain seeds to bemaintained in. For this experiment wheat grain has been chosen, thisis because it is widely cultivated around the world e.g. theMediterranean and West Asia, and is used to make flour and pasta. Thismeans wheat is a raw material crop throughout the world, and its storage isessential.To store grain effectively it is important to stop germination fromoccurring at all. Germination is the onset of growth of the embryo ina seed, this usually happens after a period of dormancy. Dormancy isthe state where germination will not occur, even if environmentalconditions are favourable. This is often an value for seeds, as itallows germination to occur in a more favourable season. In the caseof wheat seeds they need several weeks or months of prechilling beforethe will actually germinate.