THE ROLE OF ICE NUCLEATION ACTIVE BACTERIA IN FROST DAMAGE TO EARLY SOWN Solanum tuberosum var. JERSEY ROYAL

  • Philip Le Grice

Student thesis: PhD

Abstract

The present study indicated that S. tuberosum var. Jersey Royal could supercool to temperatures as low as -6ºC during in-vitro frost tests, whereas in the field freezing occurred at immediate sub-zero temperatures (between 0 and -1ºC). The microbial flora upon the early. sown S. tuberosum var. Jersey Royal did not contain INA bacterial species active at warm sub-zero temperatures. Plants inoculated with a strain of Ps. syringae (84:27) containing type 1 active nuclei readily froze at -2 to -3ºC. Applications of leaf surface water applied to plants during in-vitro frost tests resulted in nucleation temperatures comparable to those measured in the field. Applications of leaf surface water initiated freezing in whole plants during in-vitro frost tests at temperatures warmer than those caused by Ps. syringae (84:27). Thus field frost kill and ice nucleation in the presence of leaf surface water occurred at temperatures warmer than type 1 INA bacterial nucleation temperatures. Exogenous foliar applications of ethylene glycol applied in the presence of leaf surface water led to enhanced supercooling and frost avoidance during in-vitro frost tests and during field frost events. It was concluded that modifying the formation and freezing of leaf surface water would be more likely to provide a frost control strategy applicable to the field crop than frost control through manipulation of phylloplane microorganisms.
Date of Award1993
Original languageEnglish
Awarding Institution
  • University of Plymouth

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