1920.] 



History of a Grain of Wheat. 



625 



present discontents would be more wheat, and as the limits of 

 potential wheat land have almost been reached the present pro- 

 blem is that of getting more wheat out of the land we possess. 



Life of the Wheat Grain. — On examination the grain of 

 wheat will be found to consist of a tiny embryo, tile part which 

 is alive, together with a much larger store of food called the 

 endosperm, the function of which is to nourish the embryo until 

 it can push a green leaf above the ground and begin to feed upon 

 the air and the soil. Our food supply is the store which the plant 

 accumulates to feed the embryo, for flour is nothing but the 

 endosperm of the wheat berry in a powdered condition. As long 

 as it is dry the embryo cannot draw upon the store in the endo- 

 sperm. Since the embryo has to consume something in order to 

 maintain its life it soon dies from exhaustion of its own substance, 

 and with it the whole grain dies even though the endosperm is 

 still unaltered. When stored some grains of wheat will die within 

 a year, many more in two years, and very few will survive for 

 such a period as 10 years. The idea that grains of wheat stored 

 up with mummies in ancient tombs can be made to give a crop is 

 a pure error. 



Many experiments have been made in recent years in order to 

 ascertain whether the seed cannot be excited by electricity or 

 by steeping it in some nutrient fluid before it is sown, by which 

 means it can be made to grow better and give a bigger crop. 

 The results of these experiments, however, are very dubious. 

 After all. the seed is only a means of starting the embryo into 

 business. How well it will grow after the first week or two and 

 what yield it will give depends upon the later development, which 

 is determined by the soil, the available manure, the weather and 

 other factors, quite apart from the seed. Xone of the exciting 

 processes can add anything to the stock of energy contained in 

 the seed and can therefore have little to say to its ultimate 

 development, provided the seed is initially capable of starting 

 at all. 



Influence of Eate of Sowing Wheat on the Yield. — In the 



ordinary way in this country wheat is sown at the rate of about 

 2 J bushels to the acre, and the average yield is about 32 bushels, 

 or a thirteenfold yield. Now an isolated wheat plant is capable 

 of giving a hundredfold or even a thousandfold yield, and the 

 question is often raised of whether we are not sowing an unneces- 

 sary amount of seed. If we examine the plants along the drill 

 line in a wheat field we find that though there may be gaps there 

 are a great number of spots where the seeds have come up too 



