n8 Gardening 



The pollen grain must reach the pistil when both 

 are in the right condition or the pollen will not grow ; 



FIG. 70. Stages of growth in the 

 fruit (pods) of the bean. 



the ovules will not be fertilized, and no 

 fruit or seed will be produced. A pol- 

 len tube fertilizes only one ovule, and so ' 

 at least as many different tubes must 

 grow down through the pistil as there 

 are seeds which develop later. 



During fertilization the egg cell and a 

 sperm cell combine and make one cell. 



This new cell begins to grow and 

 divide, and this growth is kept up until the embryo is 

 formed. Meanwhile, the ovule develops into the seed, 

 and the pistil enlarges to become the seed pod. 



Importance of the pollen parent. The little plants in 

 the seeds borne by a bean plant all have the same mother. 

 But the embryos in two seeds that lie side by side in 

 the same pod may have different plants for pollen 

 parents. If good and poor plants are allowed to bloom 

 together, some of the seeds on even the best plants may 



