63.The translocation of organic solutes in sieve tube members is supported by: A. Root pressure and transpirational pull B. P-Proteins C. Mass flow involving a carrier and ATP D. Cytoplasmic streaming
Correct option is C) According to mass flow hypothesis the transport of organic solutes takes place from source to sink, this transport also depends on metabolic energy. According to cytoplasmic strearming hypothesis (which was given by de Vries, 1885) the transport of organic solutes takes place by combination of diffusion and cytoplasmic streaming. Cytoplasmic streaming carry organic solutes from one and to the other end of sieve tube. P-proteins has a role as defence against phloem feeding insects and sealing of damaged sieve tubes. So, the correct answer is 'Mass flow involving a carrier and ATP'.
