Research On Compensatory Effects Of Growth Under Simulated Water Stress And Rewatering On Maize

Compensatory effects of agronomic, physiological, biochemical properties and mechanism under water stress and rewatering were investigated by simulated water stress experiment by PEG and field experiments on Maize Nongda-108. The results indicated that compensatory or over-compensatory effects of agronomic and ecological characters behaved primary on improvements of root activity, root form, growth rate, photosynthesis rate, photosynthesis potential after rewatering while restrain effects appeared during stress period. Leaf photosynthetic rate, root activity, growth rate and activity of photosynthetic system II could be higher than controlled treatment (CK) and resulted in over compensatory effects. Compensatory effects related to stress periods of growth stage, stress duration, stress severity and forming periods of leaves and root. Leaves formed before water stress had lower net photosynthetic rate(Pn) after rewatering than CK and the intendancy was enhanced with severity of stress. The leaves formed after stress had higher Pn than Ck. Roots formed before water stress had lower TTC reduced capacity both during stress time and after rewatering than CK while for the roots formed after stress were higher in TTC induced capacity, suggesting the newborn organs are the basis for over compensatory effects under water stress and stress should be exposed before the end of vegetative growth. Soluble sugar concentration increased both in root and shoot during stress time and decreased after rewatering compared to CK. A positive feedback mechanism was suggested to explain the relation between growth compensation and photosynthetic compensation depended on the synchronization of over compensatory effects of growth rate and Pn of leaves and variety in soluble sugar concentration. Finally, PPC-RAGA model was used to evaluate comprehensive effective quantificationally based on the data of simulated water stress experiments. The model could avoided subjective ingredient influences of investigator on conclusion and the results of the model fitted well with those by using traditional comprehensive evaluation, suggesting the model was reasonable if the physiological properties were chosen correctly.