The Influence of Pollination on the Respiratory 
Activity of the Gynaeceum. 
BY 
JEAN WHITE, M.Sc., 
Melbourne University. 
HE fact has now been known for some time that injuries and also small 
JL doses of poisonous substances produce a kind of feverish reaction on 
the part of the plant, resulting in a resumption or increased rapidity of 
growth, accompanied by an increase in the respiratory activity and in the 
production of heat 1 . The two latter phenomena necessarily go together, 
but an increase in the rate of growth need not always be accompanied by 
a rise in the relative respiratory activity, as, for instance, when a stem 
seems to grow more rapidly simply because the apical internodes retain the 
power of elongating for a longer time than usual. Conversely, in the case 
of an injured potato or onion, as shown by Richards 2 , the amount of growth 
is altogether disproportionate to the rise in the respiratory activity, 
and, in fact, in the case of the onion, little or no growth takes place 
after injury. 
It is evident, therefore, that when a gynaeceum begins its second 
period of growth,, as the result of pollination, the respiratory activity might 
either remain unaltered, rise, or even conceivably fall as the result of more 
active production of adult, feebly respiring cells. The latter ultimately 
takes place as the period of complete ripeness is reached, and this fall is 
slowly continued until the fruit and seed become decayed or completely 
dried. No exact comparative determinations appear ever to have been 
made of the relative respiratory activities of pollinated and unpollinated 
gynaeceums in as young a condition as possible, so that a reasonable 
comparison can be made. Naturally, if the flower is one of short duration, 
and the experiments are delayed, the unpollinated gynaeceum could only 
be expected to exhibit a lower respiratory activity, but, in the following 
investigation, care was taken to carry out the experiments while the flowers 
were quite young, and to determine the activity of respiration while the un- 
pollinated gynaeceum was still active and receptive. 
1 The literature up to 1902-1906 is given in Pfeffer’s Physiology of Plants, the English translation. 
2 Annals of Botany, vol. x, No. XL, December, 1896. 
[Annals of Botany, Vol. XXL No. LXXXIV. October, 1907.] 
