Compensation and Significance of Water Stress on Growth of Rice

A pot experiment with different controlling water treatments(CWT) during different developmental stages for two cultivars of soil water potentials strictly monitored by soil negative pressure water potential tester was conducted to study the effects of soil water on the growth,grain yield and compensation of rice in cold region.The compensation and its significance under water stress was also investigated from both ecological and agricultural perspective.The results were as followed:CWT on different levels during tillering period slowed down the growth of leaves for both cultivars,however leaves got compensation at different rates after water given back,gradually getting close to those under control.CWT on different levels during tillering period made plant height of both cultivars obviously lower than CK,however plant height increased quickly after water given back,and finally no obvious differences were seen compared to those under control.During tillering period,the compensation of culm number was little.Panicle number was still obviously lower than CK after water given back.CWT on different levels during panicle-formation period showed no compensation on plant height after water given back.The final plant height of both cultivars under treatment was obviously or extremely obviously lower than CK,mainly because water control shortened the length of the 2nd section to the 4th section of plant.However,the culm number of both cultivars showed extra compensation after water given back during panicle-formation period.The final culm number and panicle number were obviously larger than CK.Nevertheless,water control during panicle-formation period changed the distribution coefficient of materials,making the decrease of economic yield twice as much as biological yield.Therefore,extra compensation on culm number and panicle number has ecological significance but no agricultural significance.Deeper research are needed for making compensation more significant from the agricultural aspect.