Carbohydrate and nitrogen reserves in two cultivars of Japanese plum grown under organic and conventional management

Abstract

Nitrogen and carbohydrate (soluble sugars and starch) reserves were analysed in twig samples of 'Red Beaut' and 'Showtime' Japanese plum (Prunus salicina Lindl.) cultivars cultivated in two similar experimental orchards under organic and conventional management. 'Red Beaut' is a vigorous cultivar while 'Showtime' is a middle to low vigorous cultivar. Both cultivars exhibited delayed flowering and premature defoliation under organic management. In general, there were no differences in the concentration of reserves between the two types of management for either of the two plum cultivars, and, likewise, no differences were observed between cultivars, regardless of their vigor. Additionally, reserves were also analysed in plantlets of 'Mariana 2624' rootstock (Prunus cerasifera Ehrh × Prunus munsoniana W. Wight & Hedrick) grown in a growth chamber that simulated conditions of spring and autumn periods and subjected to organic or mineral fertilisation. Plants subjected to organic fertilisation were smaller and defoliated earlier, but the sizes of carbohydrate and nitrogen reserves were similar to that of plants grown with mineral fertilisation.

Keywords

• prunus salicina
• organic farming
• reserves
• defoliation
• tree vigour