PART II. GREEN PLANTS MAKE THE 

 FOOD OF THE WORLD 



UNIT V 

 WHY DO SEEDS GERMINATE? 



Preview. We have seen in a previous unit that the pollination 

 of flowers usually results in the growth of a fruit containing 

 seeds from which new plants grow. The purpose of the next 

 few pages is to show how this baby plant, or embryo, grows into 

 an adult. Every boy and girl knows that a dry seed, after lying 

 dormant and apparently dead sometimes for months, will wake 

 up and show signs of life when certain outside conditions are 

 favorable. Evidently some conditions outside the seed start 

 the growth of the little baby plant within the seed coats. There 

 are several things which are absolutely necessary for germination, 

 as this beginning of growth is called. The seed must first be pro- 

 vided with a protective coat which keeps the delicate baby plant 

 within from being harmed. Then it must be able to live for long 

 periods under adverse conditions such as extreme dryness or lack 

 of soil. Many seeds, especially those of weeds and some garden 

 seeds, such as the radish, cabbage, carrot, cauliflower, cucumber, 

 and turnip, may live for as long as ten years before being germi- 

 nated, but the average age that a seed lives is much less than this. 

 The stories of germinating of wheat found in the Tombs of the 

 Pharaohs may be disbelieved, although recently some lotus seeds, 

 believed to be at least four hundred years old, were taken from a 

 dried lake bed in the Gobi Desert, and were successfully germi- 

 nated. But the reason that these seeds retained their vitality was 

 because they were protected from decay by the peat bog in which 

 they were embedded. 



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