| MadSci Network: Botany |
Monocots generally cannot be grafted because they lack a vascular cambium. The scattered vascular bundles in their stem cross sections make it very difficult to match up vascular bundles between stock and scion. The more distantly species are related the less likely they can be grafted together. There are few examples of successful grafts between species in different families, therefore, apples in the Rose Family (Rosaceae) will be unlikely to graft with oaks in the Beech Family (Fagaceae). Walnut and hickory are also in different genera so would be unlikely to form successful grafts. Pin oak and black oak would be more likely to graft because they are in the same genus. Hartmann and Kester (1983) note that distantly related oak species may initially form a graft but graft incompatibility eventually occurs. Pines and oaks would be even less likely to graft because they are not only in different families but in different phyla. Pines are gymnosperms, and oaks are angiosperms. You can find grafted oaks for sale but most are grown from seed. You don't see too many grafted oaks because there are not as many cultivars for oak as for many other tree species. Oak cultivars, such as Quercus robur 'Argenteo Marginata' and 'Atropurpurea' are likely to have been grafted. Oak tree roots of the same species often naturally graft together, which can allow diseases, such as oak wilt, to spread. Research by Frank Santamour found that differences in cambial peroxidase enzymes between stock and scion correlated with graft incompatibility for trees. If stock and scion had uniform enzymes patterns, they were graft- compatible. This provides a good way to easily screen trees. The exact causes of graft incompatibility have not been well studied. In some cases, a graft transmitted virus eventually causes the graft to fail. Chemicals can lead to graft failures. Some pear cultivars will not graft with quince because quince produces a cyanogenic glucoside named prunasin that harms the pear tissue (Hartmann and Kester (1983). The reason fruit trees are "really good at grafting" is more because people graft them so much and have gotten good at it. Many other species are fairly easy to graft including many nut trees, many ornamental trees and dwarf conifers. If it was necessary to graft more types of plants, it is likely that successful techniques could be developed within the limitations that best success is within a species or between closely related species. References Re: Is it possible to graft branches of a different but related plant specie? Grafted cacti Santamour, Frank. TREES FOR URBAN PLANTING: DIVERSITY UNIFORMITY, AND COMMON SENSE Grafting and Budding Oak wilt Oak grafting Quercus robur 'Atropurpurea' Hartmann, H.T. and Kester, D.E. 1983. Plant Propagation: Principles and Practices. Englewood Cliffs, NJ: Prentice Hall.
Try the links in the MadSci Library for more information on Botany.