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The investigation is aiming to look at transpiration.

Extracts from this document...

Introduction

NAME: AMAKA ARARAUME GROUP: B SUBJECT: BIOLOGY TITLE: TRANSPIRATION DATE: 25/10/03 AIM The investigation is aiming to look at transpiration. A range of different conditions will be used to determine the rate of transpiration in different plants {xerophytes and mesophytes}. I will also be comparing the rate of transpiration in xerophytes and mesophytes. PREDICTION The rate of transpiration in mesophyte will be higher than that in xerophytes. This is simply because: Xerophytes are plants that live in places where water is short of supply e.g. the desert. Here the rate of transpiration may exceed the rate of transpiration may exceed the rate of water uptake from the soil. These plants have control over the volume of water that they absorb, and hence their water balance depends on their ability to limit water loss. Any feature that significantly reduces the evaporation of water from aerial parts of the flowering plants, can be considered to a xeromorphic adaptations. Plants with these adaptations can be called xerophytes. They show the following adaptations: {a} roots are well developed: they grow down to the depth of the ground if necessary and branch extensively in order to absorb water from as large an area aw possible. {b} the presence of epidermal hairs: these trap humid hair thereby reducing the water potential gradient and hence the rate of transpiration. {c} the number and distribution of stomata: stomata may be confined to pits or grooves on the underside of the leaves, so that humid hair is trapped and transpiration rate decreases. {d} reduction in the surface area of the leaves: there often is reduction in the surface area to volume ratio, resulting in decrease in the area of leaf blade where stomata are situated. There may be a corresponding increase in the thickness of the leaf blade. This also helps in decreasing the rate of transpiration. {e} curling or rolling of leaves into a cylindrical shape, reducing the surface areas of leaves: Leaf rolling for example in marran grass, enclose the upper epidermis, where stomata are situated. ...read more.

Middle

TIME LEFT IN THE SOLUTION: This will be kept constant as possible. This is to reduce the chance of irregular results being obtained. MEASURING METHOD: there are a number of ways of measuring the volume of water given off during transpiration. The fundamental method is using a ruler to measure it. This is inaccurate as you may take readings above the meniscus. A better way to measure the volume of water is at eye level. If the volume of water is not measured at eye level, then the volume of water uptake would be wrong, this could lead to lead to wrong results being obtained, which could also lead to a wrong graph, and wrong conclusions. EQUIPMENT USED: a potometer was used to measure the rate of transpiration from the mesophyte and the xerophyte plant. The potometer is very reliable in measuring the rate of transpiration and should be set up carefully. It should be set up underwater to prevent air bubble forming. If a n air bubble forms it will form an air bubble form in the column, then the column of water breaks then the and the difference in pressure between the water at the top and the water at the bottom cannot be transmitted through the vessel. We say that there is 'air lock'. This can significantly reduce the rate of transpiration in the mesophyte and xerophyte plants, and hence reduce both the accuracy and reliability of results. An electric fan was used as opposed to a hair dryer, so you do not have to take into account heat. This is because the hair dryer not only provides a source for wind but also heat as well and this could alter the results obtained. Using a plant such as a plant such as the cactus to measure the rate of transpiration in xerophytes would have given us a different result. The rate of transpiration would have been much lower because cactus are xerophytes that are found in the desert and they have more feature to minimise the loss of water such as flattened photosynthetic stems that store water. ...read more.

Conclusion

Xij = ? + ?i+ ?j + ?ij ,where ? = the overall mean ?i= mean effect of the ith level row factor relative to ? {plant i} ?j= mean effect of the jth level of column factor relative to ? {condition j} ?ij = the random variation in the observation ?? = ?? ? ?ij ? N(0, ?2) Total about mean = 0.4342 - 2.202/12 = 0.030867 Between plants = 0.872 + 1.332/6 - 2.202/12 = 0.01763 Between conditions = 0.42 +0.462 +0.322 +0.422 +0.302 + 0.302/2 - 2.202/12 = 0.01187 source SS df MS F Between plants{rows} 0.01763 (2-1)= 1 0.01763 74.3 Between conditions {columns} 0.01187 (6-1)= 5 0.002374 10 residual 0.001367 5 0.0002374 Total about mean 0.030867 (12-1)=11 Test at 5? significant level : Ho: no difference between plants Ho: no difference between conditions H1difference between the plants H1: difference between the conditions F(1,5)(0.95) =6.61 F(5,5)(0.95)= 5.05 Critical region, F? 6.61 critical region, F? 5.05 74.3 ? 6.61, so reject Ho and conclude 10?5.05 so reject Ho and conclude That there is a significant difference that there is low difference between Between plants the conditions Using the analysis variance, I was able to prove that there is a difference I volume of water lost from the two plants, and that this volume of water is dependent on the condition. This is because when I was testing for a difference in plants used, my critical region was greater than 6.61, and from the table I calculations I obtained 74.3 which notably greater than 6.61. this will lead to me rejecting Ho{ null hypothesis} and concluding that there is a great difference between the plants. For my second testing the critical region is greater than 5.05, and I obtained 10 from my calculation, and this would lead to me rejecting Ho and concluding that although there is a difference between the two conditions, it is not very high. ...read more.

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