Elevated Putrescine Levels in Grapevine Leaves That Display Symptoms of Potassium Deficiency

Abstract

Leaves were collected at fruit set from Thompson Seedless and Flame Seedless vines exhibiting characteristic symptoms of potassium deficiency, and from nearby vines without symptoms. The polyamines spermidine, spermine and the diamine putrescine (1,4 diaminobutane) were assayed in symptom and non-symptom leaves. In one vineyard the putrescine level was found to be more than 30 times higher in symptom leaves than in normal leaves, and in a second vineyard the difference was greater than 21-fold. The spermidine and spermine levels were not elevated. Leaves showing early season potassium deficiency symptoms (also known as "spring fever" or false potassium deficiency) were also collected and analyzed. In this case, leaves with symptoms had 5.5 times as much putrescine as ones without symptoms even though the potassium levels in the symptom leaves were normal or the same as non-symptom leaves. Symptom leaves on shoots that had outgrown the "spring fever" symptoms were found to have 21 times more putrescine than recently matured leaves on the same shoot, but the potassium content was found to be the same. The results support the suggestion that "spring fever" is a false potassium deficiency but reveal that there is a similarity in the two disorders with regard to the accumulation of putrescine.