Physiology and plant pathology

Abstract

The impact of physical sciences, particularly biochemistry, has played a significant role in understanding etiology and syndrome in pathogenesis. Critical tissue respiration and enzyme changes, deranged carbohydrate and nitrogen metabolism, transpiratory disturbances and ionic imbalance produced by fungal toxins, exaggerated auxin relationships, formation of abnormal metabolite (s) (phytoalexins) have all contributed to a better understanding of the 'sick' plant. Plant virologists have made phenomenal progress in the applied field of the biochemistry of the infected plant and some of the recent researches on the nature of viruses and control measures adopted are worth emulating in other fields of plant pathology. A new field is developing round environment and disease proneness. This has reference to the rice blast disease where low nyctotemperatures for a long enough period makes for alterations in the nitrogen metabolism of the host and is governed by the balance between primary nitrogen metabolism and secondary metabolic events leading to synthesis of structural metabolites.