60 



PHYSIOLOGICAL PROCESSES IN PLANTS 



Observations. 1. Tabulate the daily observations as fol- 

 lows : 



Conclusion. What sort of temperature is best for germi- 

 nating seeds ? Reasons ? 



c. Oxygen 



Method. Fill a wide-mouthed bottle nearly full of moist 

 sand. Put twenty soaked peas in. this bottle, and seal it air- 

 tight. Put as many soaked peas in a similar bottle, but leave 

 uncorked. Observe results for a week. 



Observations. 1. Tabulate the daily observations as fol- 

 lows : 



NUMBEK OF PEAS SPROUTED 



Conclusions. 1. Do sprouting seeds need oxygen ? Rea- 

 sons for your answer. 



2. What element have you learned is in the air ? 



3. What happens when oxygen combines with any other 

 substance, as carbon or food ? 



4. Do germinating seeds need food ? If so, what else do 

 they need in order to set free the energy contained in the food ? 

 (See Prob. I, b). 



5. What is one of the main reasons farmers plow and har- 

 row the soil ? 



