1 Leaf and leaf bud cuttings For leaf cuttings, the entire leaf blade, section of the leaf blade or leaf blade and petiole can be used for propagation. New adventitious shoots and roots need to form to develop a new plant. These usually form along the cut leaf veins on the leaf blade or the base of the petiole. Because the leaf must develop both a new shoot and root system, this process can take a long time. Therefore, leaf cuttings are sensitive to over watering and high humidity is often more successful than mist propagation. Only a limited number of plant species can be propagated via leaf cuttings. These include Sansevieria, Peperomia, certain Begonia, African violet (Saintpaulia), and Cape primrose (Streptocarpus). Also, numerous succulents propagate as leaf cuttings including jade plant (Crassula), Sedum, and Sempervirens. Sedum Peperomia Sanseveria African violet Variegated plants that are chimeras do not propagate true-to-type from leaf cuttings. Variegation in chimeras is caused by the inability to produce chlorophyll in one of the cell layers in the meristem. New adventitious shoots are derived from a single cell layer in the leaf. Therefore, new shoots will be all green or white rather than variegated. 2 In species that can not produce adventitious shoots from leaves, leaf-bud cuttings are an alternative. A leaf-bud cutting contains a single leaf and a small portion of the stem containing a vegetative bud. This is a typical way vines are propagated. It is also a good alternative for propagating true-to-type variegated plants. Leaf and leaf-bud cutting lab exercises 1. Simple observation: Use your Forsythe pot to observe leaf and leaf-bud cutting propagation. Leaf cuttings: Cut a one square inch segment from the leaf of Begonia or Streptocarpus and across the bottom of the leaf in Peperomia and insert the proximal end into the substrate. Lay the Crassula cutting on the surface without any cutting. Leaf-bud cuttings: Cut a single node containing one leaf (for alternate-leaved plants) or two (for opposite-leaved plants) and place the node beneath the substrate and the leaves above. Use plants like Hoya, ivy, Pathos (Scindapsus) and Philodendron. Observe where the new shoots form on the cuttings. 3 2. Experimental observation: Objective: To observe the location of new shoot formation in leaf blade vs. blade + petiole cuttings in African violet and peperomia. Procedure: Select 3 cuttings per treatment for each species. Treatment: 1. Prepare leaf blade cuttings by removing the lower 1/3 of the leaf with a sharp razor blade. Insert the cut edge into the substrate ensuring good contact and covering with the substrate. 2. Prepare leaf blade + petiole cuttings by removing only a small portion of the petiole with the razor blade. Insert the petiole into the substrate leaving the entire leaf blade above the substrate. 3. Use one small flat with for each species. The substrate is 1 part peat-lite: 1 part perlite. Place the container into a plastic bag and move to the mist bench. 4. After one month, evaluate shoot and root formation. 3. Experimental observation: Objective: To observe shoot and root formation in leaf vs. leaf-bud cutting in English ivy. Procedure: Select 3 cuttings per treatment. Treatment: 1. Prepare three leaf blade + petiole cuttings by removing only a small portion of the petiole with the razor blade. 2. Prepare three leaf-bud cuttings by removing a single node from the stem and leaving only a small portion of the original stem around the leaf. 3. Use one small flat with a substrate is 1 part peat-lite: 1 part perlite. Insert the petiole (or petiole +stem) into the substrate leaving the entire leaf blade above the substrate. Place the container into a plastic bag and move to the mist bench. 4. After one month, evaluate shoot and root formation.