中国沙棘、俄罗斯沙棘和俄罗斯沙棘×中国沙棘光合特性及影响因子

Photosynthetic Characteristics of Chinese Seabuckthorn,Russian Seabuckthorn,Russian Seabuckthorn×Chinese Seabuckthorn and Their Influence Factors

在陕北黄土丘陵沟壑区用LI-6400光合仪对中国沙棘、俄罗斯沙棘和俄罗斯沙棘×中国沙棘光合特性及影响因子进行了测定。测定结果表明三者的光合速率、气孔导度、胞间CO2浓度、蒸腾速率日变化均为"双峰"曲线。中国沙棘光合"午休"现象较轻,日光合速率和午后光合速率、气孔导度、胞间CO2浓度、蒸腾速率极显著(p<0.01)高于俄罗斯沙棘和俄罗斯沙棘×中国沙棘。中国沙棘光合作用最适气孔导度、大气CO2浓度、空气相对湿度比俄罗斯沙棘小,最适胞间CO2浓度、蒸腾速率、气温、光合有效辐射比俄罗斯沙棘高。中国沙棘在最适气孔导度、胞间CO2浓度、蒸腾速率和大气CO2浓度下的光合速率比俄罗斯沙棘高;在最适气温、空气相对湿度、光合有效辐射下的光合速率比俄罗斯沙棘低。俄罗斯沙棘×中国沙棘光合"午休"现象比中国沙棘强,比俄罗斯沙棘弱,午后光合速率与俄罗斯沙棘相近;俄罗斯沙棘×中国沙棘最适气孔导度、大气CO2浓度高于中国沙棘和俄罗斯沙棘,最适胞间CO2浓度低于中国沙棘和俄罗斯沙棘,最适蒸腾速率、气温、空气相对湿度、光合有效辐射居于中国沙棘和俄罗斯沙棘之间。俄罗斯沙棘×中国沙棘在最适气孔导度下的光合速率高于中国沙棘和俄罗斯沙棘;在最适胞间CO2浓度、蒸腾速率、气温、大气CO2浓度、空气相对湿度、光合有效辐射下的光合速率低于中国沙棘和俄罗斯沙棘。中国沙棘、俄罗斯沙棘和俄罗斯沙棘×中国沙棘的光合速率均与上午的气孔导度、胞间CO2浓度、蒸腾速率、气温、大气CO2浓度、空气相对湿度、光合有效辐射显著相关,均为"抛物线"关系。

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 LI-6400 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 double-peak 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.