Effect of irrigation on intensity of respiration and study of sugar and organic acids content in different development stages of Lonicera kamtschatica and Lonicera edulis berries

Abstract

This article investigates the effect of irrigation on the intensity of respiration of Lonicera kamtschatica and Lonicera edulis during different stages of fruit development in the conditions of Nitra in 2002 and 2003. Changes in organic acids and sugar content during fruit ripening process were also monitored within non-irrigated variant of Lonicera kamtschatica and Lonicera edulis in 2002. The intensity of respiration can be divided into 4 stages corresponding with intensive cell division of fruit (stage I), enlargement of fruit pericarp and fruit colouring (stage II) and fruit softening (stage III). In the early stages of fruit development the intensity of respiration increased (stage I), then declined (stage II), and then increased again to the "climacteric peak" (stage III). In this stage fruit achieved the best quality for direct consumption; it was characterized by the highest sugar content (9.5% in Lonicera kamtschatica and 7.7% in Lonicera edulis) and the lowest organic acids content (3.61% in Lonicera kamtschatica and 3.32% in Lonicera edulis). After this stage, fruit became overripe and its quality declined (stage IV). During the two-year observation, there were no statistically significant differences in respiration intensity of fruits of Lonicera kamtschatica and Lonicera edulis grown with or without irrigation.