Explain the cohesion-tension theory, apoplast and symplast pathways, and the process of transporting manufactured food to the tuber.

Hey Luma, good to see you again. Here are the answers to your questions: 1. The most acceptable concept for the mechanism of water movement in plants is the cohesion-tension theory. 2. Explanation of terms related to water movement: a)* Apoplast pathway: Water moves through the non-living parts of the plant, specifically the cell walls and intercellular spaces, without crossing any cell membranes until it reaches the endodermis. b)* Symplast pathway: Water moves from cell to cell through the cytoplasm and plasmodesmata, which are small channels connecting the cytoplasm of adjacent cells. c)* Vacuolar pathway: Water moves from cell to cell by repeatedly entering the cytoplasm and vacuole of one cell, then exiting to the next cell. This involves crossing the cell membrane and tonoplast multiple times. 3. Processes involved in transporting manufactured food (sugars) to the tuber: Sugars (primarily sucrose) produced in the leaves (source) are actively loaded into the sieve tube elements of the phloem. This increases the solute concentration within the sieve tubes, causing water to move in from the xylem by osmosis, which generates high turgor pressure. This pressure drives the bulk flow of the phloem sap through the sieve tubes towards the tuber (sink). At the tuber, sugars are actively unloaded from the phloem and converted into starch for storage, reducing the solute concentration. Water then moves out of the phloem by osmosis, maintaining the pressure gradient. 4. Definitions of terms in plant coordination: a)* Photoperiodism: The physiological response of plants to the relative lengths of day and night. It influences processes like flowering, dormancy, and leaf fall. b)* Phytochrome: A photoreceptor pigment in plants that exists in two interconvertible forms (Pr and Pfr) and is responsible for detecting red and far-red light, regulating responses such as flowering and seed germination. c)* Vernalization: The requirement of a cold period for some plants to initiate or accelerate the flowering process. It ensures that flowering occurs at an appropriate time after winter. 5. Role of growth hormones: a)* Auxins: Promote cell elongation in shoots, apical dominance, root initiation, and fruit development. They also inhibit lateral bud growth and abscission. b)* Ethene (Ethylene): A gaseous hormone that promotes fruit ripening, senescence (aging) of leaves and flowers, and abscission (shedding) of leaves, flowers, and fruits. Send me the next one 📸