Potassium Deficiency in Sugar Cane

Abstract

Cuttings of Louisiana Purple sugar cane were grown in quartz sand in glazed earthenware crocks. Nutrient solutions were based on Shive''s best solution and contained the following p. p. m. K: 703.8, 0.0, 3.9, and 39.0. In 4 mo. a gradation in growth was obtained as well as die-back and discoloration symptoms of K starvation; 3.9 p. p. m. K was insufficient for the best growth. The K-deficient plants had greatest diastase activity in all organs except roots, in which activity was equal. The blades of the controls had greater invertase activity than the K-deficient plants. All organs of the controls had greatest peptase activity. Ereptase was the same in all plants. The catalase activity was greater in plants supplied with K, with the exception of the roots. Equalizing the K content of blades did not equalize the invertase activity and therefore it seems likely that K may play a role in the formation of invertase. K-deficient plants had greater % of total sugars, reducing sugars, and sucrose. Greater lignification occurred in K-deficient plants, while greater cutinization was found in plants supplied with K. Abnormal distribution of vessels in pith of roots, small size of vessels and parenchyma cells of stems, large cavities in cortex of roots, and un-derdevelopment of root hairs occurred in K-deficient plants. Suggestions are made regarding the causes of symptoms of K starvation, as well as the greater resistance toward low temp. and diseases found among plants supplied with K; and an attempt is made to link together in a chain of cause and effect the derangements in morphology and physiology.