Week 10


Intravenous injection after drying under the sun:

The following table shows the change in color along the sides, since the veins did not show much of a color change, when different solutions were injected into the veins after drying under the sun for about 24 hours. The results were the same as mentioned earlier with the sides turning green for pH 12, the maximum, and gradually turning reddish pink for pH 2, the minimum.

pH change Color of the leaf after 20 minutes(approx.)
pH 12 2177379049_b3e22b3c05_m.jpg (green)
pH 12 to 10 2177379103_71c3b13f55_m.jpg(colorless – the green has vanished)
pH 10 to 7 2177379163_55c76efab1_m.jpg(purple-blank-normal color of cabbage)
pH 7 to 4 2177379227_35c1cc5e3a_m.jpg(pink)
pH 4 to 2 2177379371_9de8f5e790_m.jpg (reddish pink)
pH 2 to 4 2178170892_a8517513c9_m.jpg (colorless – the reddish pink has vanished)
pH 4 to 7 2177379519_bbab2126ee_m.jpg(purple-blank-normal color of cabbage)
pH 7 to 10 2177379607_332540aeeb_m.jpg(half-white)
pH 10 to 12 2177379673_94ba60e9a3_m.jpg(green)


Eventhough the leaf was sun dried, there was not much of a difference in results when compared with the results obtained without drying. In other words, the color change was not as expected. When comparing the soaking method with the intravenous injection method, we can say that in the case of intravenous injection, the sides turned green at first for pH 13 and gradually turned colorless for solutions of other pH. The results due to soaking are explained as below.


Hence, I conclude that the pigment responsible for the color change (chromophores) is present on the surface of the leaf and so the color change in the first method is perceptible. The pigment is absent in the veins and hence, intravenous injection does not work very well.

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