Number of living plant cell where nucleus is absent :
Collenchyma ,chlorenchyma , sieve tubes , sieve cells , arenchyma .
Give ans with reason .

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Please find below the solution to the asked query

Sieve tube elements are living components of phloem that lack nucleus at maturity.
 
Sieve tube elements/cells are the components of phloem. They do not carry water instead they carry food in plants. They lose nucleus and other organelles at maturity to form hollow tubes for carrying food. The sieve tube elements are connected to companion cells by plasmodesmata. These companion cells help them in carrying out all the metabolic and cellular functions by transfer of materials through plasmodesmata. Hence, they do not need nucleus as such to carry out the function of transport of food instead they depend on companion cells for their function.

Hope this information will clear your doubts about the topic.
Regards  
 
Hope this information will clear your doubts about the topic.
Regard