human body ppt

One of the best ways to learn more about food is to grow some of the fruit and vegetables from exotic fresh produce that you can buy in supermarkets. Over the years Ive grown avocados, litchi, rice, lentils, chickpeas, figs, citrus fruits, lemon grass, ginger, chilli, cape gooseberries, squashes, passionfruit, sesame and pomegranates from supermarket produce - but this was the first time Id ever grown sweet potatoes Ipomoea batatas . After a slow start the tuber produces some healthy vigorous shoots but then .... ...... these white granules appeared on the leaves. At first I thought they might be some small insect pest but ... .... a closer look revealed that they were part of the leaf surface ....and under the microscope ... ..... they turned out to be clusters of swollen, glassy secretory hairs, known botanically as colleters. Theyre present on upper and lower leaf surfaces. At higher magnification you can see how inflated the hairs are. They are full of what appears to be .... ........