Abstract
The purpose of this study was to identify the physiological mechanism underlying the effects of high temperature and waterlogging on summer maize. The stem development and yield of the maize hybrid Denghai 605 in response to high-temperature stress, waterlogging stress, and their combination applied for six days at the third-leaf, sixth-leaf, and tasseling stages were recorded. The combined stresses reduced lignin biosynthetic enzyme activity and lignin accumulation, leading to abnormal stem development. Reduction of the area and number of vascular bundles in stems led to reduced dry matter accumulation and allocation. Decreased grain dry weight at all three stages reduced grain yield relative to a control. In summary, high temperature, waterlogging, and their combined stress impaired stem development and grain yield of summer maize. The combined stresses were more damaging than either stress alone.
