The physiological mechanism of the increment of C3 plant leaf water use efficiency under high atmospheric CO_2 condition

Elevated atmospheric CO2 is not only a reaction caused by a series of climate change,but also has a significant impact on plant physiological process and growth.This article analyses the research progress on the leaf stomatal density,stomatal conductance,plant photosynthesis,transpiration and water use efficiency under the condition of high atmospheric CO2 enrichment.It is found out that under such condition stomatal density decreases significantly,and stomatal conductance also decreases significantly(30%).Plant photosynthesis increases by 50%～100% in general.The decreased rate of transpiration may differ on different plant,about 10%～70%.The water use efficiency(WUE) increases,and its increasing rate under adequate nitrogen treatment is more obvious than that under inadequate treatment.And analysis is made of the interrelationship between them.The conclusion can be used as theoretical basis for breeding crop varieties with high water use and water-saving efficiency.