Abstract
Recovery of dry-matter production after drought stress is an important factor of drought resistance in plants. Napiergrass, whose dry matter weight largely decreased by soil drought treatment, increased dry-matter weight vigorously under the well-watered soil condition. In this study, the changes in total dry-matter weight (TDW), leaf area (LA) and photosynthetic rate (Pn) in napiergrass during and after the soil drought treatment were compared with those in maize grown in the same pots to clarify whether TDW of napiergrass quickly recovered after the soil drought treatment. In maize plants, TDW and LA during six days soil drought were as high as those in the control plants. Plant growth rate (PGR), relative growth rate (RGR) and net assimilation rate (NAR) under soil drought treatment remained as high as those in the control plants, but decreased to approximately 50% of that in the control plants after re-watering. In napiergrass, on the other hand, TDW and LA decreased under six days soil drought treatment to 70% and 30%, respectively, of control. However, LA increased to 50% of that in the control plants at the 6th day after re-watering. NAR did not decrease under drought stress though PGR and RGR decreased. Pn decreased slowly under soil drought condition but recovered quickly after re-watering. The increase in TDW was slight, but LA and Pn quickly recovered within six days after drought treatment.
