136 BOTANY FOR BEGINNERS CHAP, x 



Heat is produced by respiration. Plants respire (i) In both light 

 and darkness ; (2) In an atmosphere containing free oxygen ; (3) At a 

 certain temperature a few degrees above the freezing point. 



The parts of plants which respire are (i) Every living cell, (2) Ger- 

 minating seeds, (3) The growing parts of plants, (4) The flowers. 



Nitrogen. Most green plants obtain the nitrogen necessary for their 

 growth from the nitrates in the soil. 



Leguminous Plants obtain most of the nitrogen for their growth 

 through the agency of Bacteria, which grow in tubercles on their roots. 

 They are said to live in Symbiosis with the Bacteria, i.e., there is a life- 

 partnership between them. 



QUESTIONS ON CHAPTER X. 



1 i ) What is meant by plant physiology ? 



(2) Explain what you understand by "division of labour"? 



(3) What do you know about 



(a) The amount of water found in plants ? 



(b) The solid matter of a plant ? 



(c) The ash left after the combustion of a plant ? 



(4) Enumerate the essential chemical elements which a green plant 

 absorbs as food from the soil ? and briefly state what is the special use 

 of each element. (1891.) 



(5) Explain why it is that starch-grains are formed in the chlorophyll 

 corpuscles when a leaf is exposed to light and air. 



(6) Explain how it is that a green plant cannot carry on its nutrition 

 in darkness (1892). 



(7) What part of its food does a green plant obtain from the air ? In 

 what form, and under what conditions, is it taken in ? (1889.) 



(8) What are the conditions necessary for the assimilation of carbon 

 by green leaves ? State the means by which you would prove that a 

 given leaf had been assimilating carbon. (1891 T.) 



(9) Give an account of the use of chlorophyll in the nutritive pro- 

 cesses of plants. ( 1 890 T. ) 



(10) From what source and in what forms do plants usually absorb 

 their nitrogenous food ? Mention cases in which the nitrogenous food 

 is absorbed from other sources and in other forms. (1887.) 



(12) Plants both absorb and give out carbon dioxide. State pre- 

 cisely the circumstances upon which each process depends. (1885.) 



(13) In what respects does the nutrition of the leguminous differ from 

 that of the other green plants ? Explain the significance of this differ- 

 ence. (1896.) 



(14) What is starch? Explain how it is that, if a green plant be 

 kept for a day or two in darkness, no starch is to be found in its leaves. 

 (1897.) 



(15) How may the necessary chemical elements for the nutrition of 

 a green plant be determined ? 



(16) What is the importance of carbon to a plant? From what 

 source does a green plant get its carbon, and how is it assimilated ? 

 (1899.) 



