Growth and Development of Horticultural Crops (1+1)

Phloem transport

1. In plant growth & development materials are moved from source to sink through xylem (acropetal) and phloem (basipetal & acropetal)
2. Lateral movement in both xylem &phloem takes place through plasmodesmata
3. Phloem –sucrose, amino acids, low quantities of growth regulators nucleotides inorganic & systemic pesticides
• The carbohydrates especially sucrose, nitrogenous substances & low quantities of growth regulators , nucleotides, inorganic substances & systemic pesticides move through phloem. But substances like reducing sugars, contact herbicides, proteins, polysaccharides, Ca, iron & most micro nutrients do not move in phloem. The mechanism of translocation follows munch’s mass flow theory.