2013 ASHS Annual Conference

Many plants, including potato, tobacco, tomato, and geraniums, are known to develop Oedema or intumescence injury. This injury develops exclusively on plants growing in controlled environment facilities compared to field grown plants. Early studies have suggested a link between light quality and Oedema. For example, UV and/or far-red wavelengths were found to mitigate this injury. Here, we report that Oedema can be mitigated by calcium nutrition. Plants of cultivars Russet Burbank and Atlantic were grown using in vitro shoot cultures in 20.4 L pots. Plants were irrigated daily to excess with a Peter’s Professional Peat Lite Special 20N–10P–20K fertilizer. For this purpose 104 g of this fertilizer was mixed with 200 L of tap water. Two calcium treatments (1 mM and 10 mM) were evaluated with 13 replications per treatment. The source of calcium was calcium chloride. About 20 days after the start of these treatments the Oedema injury was observed only on plants of the cultivar Russet Burbank. Upper canopy leaves in the 1 mM treatment had an average of 64% of the leaf area covered with injury. However, only 4% of the leaf area on average was covered with injury in the plants that received the 10 mM Ca treatment. Average leaf calcium concentration was nearly 2x in plants given 10 mM Ca as compared to the 1 mM Ca treatment. There were no other apparent growth and development differences among the two Ca treatments. These data provide evidence that Oedema injury can be mitigated by supplemental calcium and that 'Russet Burbank' is more prone to this type of injury compared to 'Atlantic'.