Download Grafting in Horticulture: Techniques, Incompatibility, and Factors Affecting Healing and more Study notes Plant Morphology in PDF only on Docsity! ESRM 411 - PHYSIOLOGY OF GRAFTING May 8, 2008 Grafting - 2 parts of same or different plant joined together so as to grow as one plant. - the parts do not grow together Scion - upper portion - can be a piece of large wood or a simple bud. (budding) Stock, Understock - root stock usually Interstock - an intermediary piece which imparts dwarfness, or get away from incompatibility of root stock and scion Reasons for grafting: *1. hard to root species, e.g., Blue spruce, apples, most fruit crops. *2. faster to get salable plant, can also hasten growth , e.g., junipers, taxus. *3. maintain a clone or habit of growth, e.g., weeping cherries or modify habit of growth - apples, pears, some in ornamentals. 4. for disease resistance - for protection of and study of virus diseases - to make a plant resistant. 5. to repair injury - girdling of stems by rodents - due to ice breakage. 6. genetics and taxonomy experiments - study to determine if plants related. 7. To change the varieties - e.g. topworking or budding trees - if variety you have isn’t in demand...newer varieties. * most important reasons SUCCESS FOR GOOD GRAFTS: this is where the art of grafting comes in. 1. have to be compatible will grow together to become one plant 2. have to have close fit between scion and stock - right moisture - cells to interlock callus 3. must have cambial contact Incompatibility in Grafting - for grafting to work, plants must be botanically related Between families - very difficult Between genera - sometimes work , i.e., pear on quince Between species - works sometimes - varieties or cultivars in same species e.g., - same strain in coleus However, in Solanaceae - potato on tomato, tobacco on nightshade..but be careful of solanin getting across Usually only dicots are grafted with success. - corn may if graft under water, get 2-3 out of 100. HEALING OF GRAFT UNION: 1. contact of cambium in good environment. 2. get callus formation. - cells are undifferentiated - great mass of usually parenchyma tissue - cells have not taken on any characteristics - usually associated with wound and healing - develop form parenchyma near cambium, not cambium itself - people don’t know if necessary or not. - get interlocking of callus, like fingers of both hands. 3. new cambium forms between the scion and stock -produced with by old cambium or callus, we are not sure. 4. get new vascular tissue, which then bridges the two parts, and it heals - forms new cambium too. FACTORS AFFECTING HEALING PROCESS: 1. graft must be clean - from disease and virus - keep equipment clean ( may be dip in fungicide or stock plants dipped) 2. Control the moisture level -waxing, shading, polyethylene 3. do at exact time of the year ( slipping) ....physiologically 4. do at proper temperature 65- 75 degrees - callus at 50 degrees - high temperature , scion buds break, no union...do NOT want buds to break until healed. - in west may white wash tree, wrap in tin foil 5. Use best technique or type of graft. When unions are not good - growth is poor, sometimes dwarfed - is called uncongeniality - get dwarfing - is usually not we are really tying to get to happen INCOMPATIBILITY: Have studied incompatibility only by symptoms: * 1. graft union breaks, does not unite well - may get delayed incompatibility, may break weeks or even years afterwards
