Title: the rate of germination in Acacia

Title: Saline stress on seed germination Aim: to check the effect of saline on seed germination.Research question:  to what extent does different concentration of saline water effect the rate of germination in Acacia tortilis?Theory:                                               Salinity  Salt is naturally present in huge quantities below Australia’s vast surface. It has built up over many thousands of years through natural processes and native plants have adapted to cope with it. Many native woodland plants have deep roots and consume large amounts of water, preventing water from leaking through the soil and reaching the water table and salt deep underground. Until European farming practices arrived, the salt remained deep underground, well beneath the fertile topsoil from which plants draw their water and nutrients. But crops such as wheat and many others have shallow roots and consume much less water than native plants. The excess water leaks through the soil and eventually reaches the ground water below. Each successive rainfall then raised the water table bringing dissolved salt from deep underground to the surface. Once it reaches and the topsoil, plants can no longer grow and eventually die off. The surface water evaporates leaving large salt deposits. This has already, and is continuing to happen on a grand scale in Australia. These salt concentrations will take many generations to reduce. The problem does not only affect growing plants but also threatens to contaminate drinking water supplies and causes corrosion of buildings, roads, and underground pipes and cables. Altogether, the costs to individuals, communities and Australia’s economy are enormous.How water brings salt to the surfaceTo understand how the salinity crisis has arisen, consider a bucket with a layer of salt at the bottom, covered with pebbles and a layer of topsoil as illustrated. If the plants can consume all the water supplied to the bucket before it reaches the pebbles, the salt stays put at the bottom. If the plants are removed or replaced with others, which consume less water, but watering continues at the previous rate, the water will reach the pebbles and eventually, the bottom of the bucket. Each watering adds to the water collecting at the bottom, progressively raising the level. The salt layer will dissolve into this ‘groundwater’ and rise up with it. Eventually, the level of salty ‘groundwater’ will reach and contaminate the soil, killing all the plants. Once the soil has been contaminated, the salt is almost impossible to remove.fig: 1.Over-watering dissolves salt and raises it to the surface Hypothesis: increasing the concentration of NaCl (sodium chloride) will have the biggest decrease in the number of germinations compared to increasing the other salt concentrations.Null hypothesis: increasing the salt concentration will have no effect on the germination of seeds.Variables:  Dependent variable: Seed germination rateIndependent Variable: The salt solutions and salt concentration Apparatus: 201 gm.- Mung beans (dry) 12 Round takeaway container (lid optional) 2- Paper towels 1 -Cling wrap (~ 15 cm piece) 1 -Rubber band 1 -Packet of salt 13 Distilled water for salt solutions 1 -Measuring jug or beaker 1 -Plastic cup 1 -Eyedropper for adding salt solution 1 -Kitchen scales for measuring salt 1 -Tweezers (shared) 1 Magnifying glass (sharedSafety:You need goggles for the salt water splashing in your eyes, and gloves so you do not transfer bacteria to the seeds.Observation: At the end of the germination period, the germination percentage and germination speed for Acacia seeds subjected to salinity treatments were calculated using appendix equations:  Final germination percentage = 100 N n GP i × =  Germination speed = == n 1i t n GS  For data analyze, we used a completely randomized design (CRD) with 3 replicates per treatments. Comparisons of germination speed and germination percentage among different salinity treatments were made using 2-way analysis of variance (ANOVA).  When significant main effects existed, differences were tested by  DuncanObservation table : Salt Concentration Total beans germinated (out of 20) Comments Day 1 Day 2 Day 3 Day 4 Day 5 No water (Dry) 0 0 0 0 0 No change by day 5 Tap water 7 19 20 20 20 Sprouts are up to 5cm long by day 5 0% 5 18 20 20 20 Sprouts are up to 5cm long by day 5 0.25% 6 14 20 20 20 Sprouts are up to 5cm long by day 5 0.50% 2 7 20 20 20 Beans sprout but there is very little growth by day 5 0.75% 1 2 4 4 4 Bean coats split but little or no growth 1.0% 0 3 4 4 4 Bean coats split but no growth – dried out by day 5 1.50% 0 0 2 3 3 Beans coats split but no growth – dried out by day 5 3.5% 0 0 0 0 0 Beans drying out         Conclusion: 1. 0.25% Salinity – Day 1 Six beans have sprouted. Sprouts are approx. 3 to 6mm long. 2.0.25% Salinity – Day 3 All 20 beans have sprouted. Sprouts are approximately 10 to 35 mm long.3. 1.5% Salinity – Day 3 Beans look very dry – 3 of the bean’s coats have split but no sprouts have grown.   Suggestions and improvements:  Plants not seeds: You can do a variation on this project by watering plants with water with different concentrations of salt to see how salt water affects the growth of plants. As the coordinator of an elementary science fair, I’ve seen students do lots of plant watering experiments using different kinds of water, or liquids other than water. but I’ve never seen a salt experiment.Different types of seeds: Radish seeds sprout quickly, but many other types of crop seeds could work as well.Plant the seeds: You could do a longer variation of this project by planting some of the seeds that sprout and continuing to water them with the same salt concentration