XVI International Botanical Congess

Callus tissue can readily develop in some wetland plants, e.g., Phragmites and rice in response to injurious agents such as phytotoxins, e.g., lower volatile moncarboxylic acids, and insects. In extreme cases callus may completely block aerenchyma in shoot bases, rhizomes and roots. In Phragmites, callus and insect bore holes can reduce or prevent convective gas flows in the rhizome system. Phytotoxins can also induce blockages in the vascular systems of these plants. Death of underground organs, including buds, may be induced by asphyxiation and/or reduced water and food supplies.