AP BIOLOGY

Detailed explanation-1: -Phloem consists of living cells. The cells that make up the phloem are adapted to their function: Sieve tubes-specialised for transport and have no nuclei. Each sieve tube has a perforated end so its cytoplasm connects one cell to the next.

Detailed explanation-2: -The phloem is composed of living cells specialized for the long-distance transport of soluble organic compounds. In gymnosperms transport occurs through sieve cells, which are interconnected by structures resembling plasmodesmata.

Detailed explanation-3: -Phloem transports carbohydrates, produced by photosynthesis and hydrolysis of reserve compounds, to sink tissues for growth, respiration and storage. At photosynthetic tissues, carbohydrates are loaded into phloem (Rennie and Turgeon 2009), a process that raises the solute concentration.

Detailed explanation-4: -The water and minerals are transported in plants by two types of conducting tissues: Xylem. Phloem.

Detailed explanation-5: -The phloem tissue is the main pathway for the long-distance transport of assimilates from source to sink organs in plants, distributing carbohydrates produced in source tissues through photosynthesis and starch hydrolysis to sink tissues where they sustain growth and respiration or where reserve compounds are stored.