4 | DISCUSSION
We found the negative effects of DS, HS and DHS around flowering on
maize grain filling. The early stress around flowering reduced kernel
weight by shortened grain filling duration, accelerated leaf senescence,
and decreased net photosynthesis in field condition. When the source
supply was sufficient by vitro
cultured in laboratory incubation, the early stress still significantly
decreased kernel weight. These results clearly showed that the
independent and combined drought and heat stress around flowering stage
had significant impact on the subsequent grain filling even with
sufficient source supply (Figure 10).