In order to understand the photosynthetic characteristics of Chinese seabuckthorn

Russian seabuckthorn

and Russian seabuckthorn× Chinese seabuckthorn

research on the 3 species and their influence factors were conducted with Portable LI26400 Photosynthesis System in the loess hilly and gully region of Northern Shaanxi Province.Results showed that diurnal courses of photosynthetic rates

stomatal conductance

intercellular CO2 concentration

and transpiration rate of the 3 species were the doublepeak type curves.Midday depression of Chinese seabuckthorn was light

and diurnal photosynthetic rates and afternoon photosynthetic rates were significantly higher than Russian seabuckthorn and Russian seabuckthorn× Chinese seabuckthorn ( p < 0.01) .Stomatal conductance

intercellular CO2 concentration

and transpiration rate in afternoon for Chinese seabuckthorn were significantly higher than Russian seabuckthorn and Russian seabuckthorn×Chinese seabuckthorn ( p < 0.01) .Optimum stomatal conductance

air CO2 concentration

and air relative humidity for photosynthesis of Chinese seabuckthorn were lower than Russian seabuckthorn

and optimum intercellular CO2 concentration

transpiration rate

air temperature

and photosynthetic active radiation were higher than Russian seabuckthorn.Under the conditions of optimum stomatal conductance

intercellular CO2 concentration

transpiration rate

and air CO2 concentration

photosynthetic rates of Chinese seabuckthorn were higher than Russian seabuckthorn.Under the conditions of optimum air temperature

air relative humidity

and photosynthetic active radiation

photosynthetic rates of Chinese seabuckthorn were lower than Russian seabuckthorn.Midday depression of Russian seabuckthorn×Chinese seabuckthorn was lower than Chinese seabuckthorn and higher than Russian seabuckthorn

and photosynthetic rates were similar to Russian seabuckthorn in afternoon.Optimums stomatal conductance and air CO2 concentration for photosynthesis of Russian seabuckthorn× Chinese seabuckthorn were higher than Chinese seabuckthorn and Russian seabuckthorn ; its optimum intercellular CO2 concentration was lower than Chinese seabuckthorn and Russian seabuckthorn ; and its optimum transpiration rate

air temperature

air relative humidity

and photosynthetic active radiation were between Chinese seabuckthorn and Russian seabuckthorn.Under the condition of optimum stomatal conductance

photosynthetic rates of Russian seabuckthorn× Chinese seabuckthorn were higher than Chinese seabuckthorn and Russian seabuckthorn.Under the condition of optimum intercellular CO2 concentration

transpiration rate

air temperature

air CO2 concentration

air relative humidity

and photosynthetic active radiation

photosynthetic rates of Russian seabuckthorn×Chinese seabuckthorn were lower than Chinese seabuckthorn and Russian seabuckthorn.Photosynthetic rates of the 3 species had significantly correlations with stomatal conductance

intercellular CO2 concentration

transpiration rate

air temperature

air CO2 concentration

air relative humidity

and photosynthetic active radiation in forenoon

and their relationships might be described by a parabola.