Antimicrobial Substances from Resistant and Non-resistant Seeds

Abstract

WHY certain plant varieties are resistant to plant pathogenic micro-organisms while others are not resistant is not understood. It is possible that resistant plants produce more antibacterial and antifungal substances than non-resistant plants in order to protect themselves against microbial invasion. This idea was advanced by Irving, Fontaine and Doolittle¹ and was tested by Little and Grubaugh². The latter investigators used the expressed juices of several resistant and non-resistant common garden plants and tested them against both plant and animal pathogenic micro-organisms. They concluded that no distinction could be drawn between the activities of the juices of resistant and non-resistant plants. Similar results were reported by Tims³. It was thought advisable to investigate seeds in an attempt to demonstrate any difference between resistant and non-resistant plants. Furthermore, the solvents used in the preparation of seed extracts was not only water but also di-ethyl ether, acetone, ethyl alcohol (95 per cent) and n-butyl alcohol. The use of organic solvents for removing antimicrobial substances from plants is the more common procedure^4,5.