Re: Do all plants need to respirate?

Yes, all plants do carry out respiration.  Respiration is carried out at 
two levels.  At the whole plant level, plants take in oxygen and give off 
carbon dioxide, just like you and I do.  At the cellular respiration 
level, cells use the oxygen in their mitochondria to produce ATP with its 
high energy bonds for cellular reactions requiring energy.  In plants, 
this is the release in a usable form of the light energy trapped during 
the photosynthetic process.  Without respiration, plants could not use the 
energy they had captured from sunlight.  We respire what we eat, plants 
respire what they make.

On the overall balance sheet, however, the oxygen used for respiration is 
much less than what is given off during the photosynthetic reactions; 
likewise, the carbon dioxide given off is much less than what is taken up 
during photosynthesis.  This is because in addition to using sugars for 
energy, sugars are also a major structural component of plants.  Plants 
are largely cellulose, which is long strings of sugar molecules.  Thus 
plants respire only a small portion of what they make.  The rest is used 
for building the plant or stored in structures that we eat and respire.