Effects of Ethylene During Storage and 1-Methylcyclopropene Pretreatment On Ultrastructure of Mesophyll Cells and Chloroplasts In Aglaonema

Exposure to ethylene resulted in increased chlorotic leaves in ‘White Tip’ but not in ‘Chalit’s Fantasy’, as shown in our previous report. This study determined the effects of ethylene and 1-MCP on ultrastructure of mesophyll cells and chloroplasts of these two cultivars with different sensitivity to ethylene. Stored control plants were neither pretreated with 1 MCP nor exposed to ethylene for 5 days during dark storage at 16 C. Two other groups of plants were pretreated with 0 or 600 nL·L^-1 1-MCP for 6 hours and then exposed to 3 μL·L^-1 ethylene during storage. All plants were placed in the indoor environments for 14 days. The lowest leaf from each plant was sampled to observe the mesophyll cells and chloroplasts after storage. Plants exposed 0 μL·L^-1 ethylene or pretreated with 1-MCP had chloroplasts that showed a typical oval shape with an intact double envelope, well-organized grana thylakoids and stroma membranes, and small plastoglobuli. Ethylene did not alter the ultrasture of mesophyll cells and chloroplasts in ‘Chalit’s Fantasy’. In contrast, ‘White Tip’ treated ethylene had few, smaller, and rounder chloroplasts, with swollen and dispersed thylakoids and large plastoglobuli.