Plant Biology and Horticultural Practices

Posted on Feb 17, 2025 in Biology

Vascular cambium is the lateral meristem in stems that produces xylem and phloem. Spongy mesophyll is a type of loosely organized tissue that allows for air exchange within the leaf. Commensalism is a symbiotic relationship where one organism benefits and the other is not harmed. A lenticel is a rough area on some stems that serves as a breathing pore for gas exchange. Photosynthesis is not a root function. A sugar beet is a modified root that has two functions: storage and propagation. Stomata are the primary structures that control excess water loss. Decreasing productivity is NOT an objective or advantage of pruning. Air layering is the process of putting soil around a node to stimulate root formation. When a horticulturist makes a cut in the stem for layering, they try to selectively cut the phloem so translocation is disrupted. If someone discovers a unique holly shrub and propagates it, they create a clone. The bottom part of a graft is called the stock, and the top part is called the scion. CAM photosynthesis is used by plants from arid or semi-arid environments that open their stomata at night. The glycolysis reaction of respiration occurs in the cytosol. The light reaction converts light energy into ATP and NADPH, which provide chemical energy. The two primary energy-carrying molecules used in living organisms are ATP and NADH. Carbohydrates are the final product of photosynthesis. The ambient level of carbon dioxide in the atmosphere is lower compared to the level needed to saturate photosynthesis. Two plants that use the C3 photosynthetic pathway are wheat and potatoes. Alternate leaf arrangement has one leaf attached per node staggered along the stem. Carnivorous plants exhibit leaf modifications allowing them to obtain part of their nutrition from insects. Collapsing is NOT a method of trapping food used by carnivorous plants. When the vascular cylinder of the root contains pith, the plant is considered a monocot. The distance between two terminal bud scars is considered a measure of annual growth. Monocot leaves have parallel venation patterns.

The increase in length of a root is the result of cell division and cell elongation. Apomixis is defined as seed production from maternal tissues without fertilization. Supplying carbon dioxide to the roots is NOT a characteristic of rooting media. To properly prune a large limb on a tree with wide crotch angles, the first cut is made on the bottom of the limb about 6 inches out. Requiring more water is NOT a disadvantage of asexual reproduction. Chemical energy is transferred through redox reactions where the oxidized chemical loses electron(s), and the reduced chemical gains electron(s). Plants that use the C4 photosynthetic pathway open their stomata during the day. Chlorophyll a mainly absorbs blue and red light. The net result of photosynthesis is that radiant energy is converted to chemical energy. Cacti use CAM photosynthesis and open their stomata during the night so that carbon dioxide can be fixed into 4C acids. Fermentation produces ethanol or lactate and ATP from glucose. Corn plants use C4 photosynthesis and open their stomata during the day so that carbon dioxide can be fixed into 4C acids. All of the above foliage characteristics are involved with limiting water loss. The function of lenticels is gaseous exchange. There is no single correct answer for a common response to cold temperatures.