The objective of our studies was to investigate the effect of high temperature on cabbage cultivars which were different in heat tolerance in terms of head formation.
We determined whether there were cultivar differences in the properties of epicuticular wax, growth parameters such as leaf number, leaf area and dry weight and whether these factors contribute to head formation under stress.
Four cabbage varieties including the Japanese heat tolerant cultivar Sousyu, were grown in pots at different temperatures in growth chambers.
The stability of the wax differed with the varieties. The wax of Kinsyun melted at a temperature of 32 °C during the day and 29 °C during the night, while the wax of the other varieties was more stable. The density of the tubes, plates or fibrils could be observed by light reflection. For Kinsyun as the low density caused a low reflection, the leaf colour was green, while for Sousyu the leaf colour was blue/white for Akiou, green/ blue and for Braunschweiger, blue.
We conclude that the function of cuticular wax in limiting cuticular transpiration is a product of the architecture of the deposits and the quantity of wax per unit area of leaf surface. Neither the wax structure nor the amount of eight varieties could be correlated with heat tolerance in terms of head formation.