水分胁迫对牡丹光合和荧光特性的影响

[目的]研究水分胁迫条件下牡丹光合指标及荧光特性变化。[方法]以胡红、洛阳红两种牡丹品种为试验材料,进行不同的水分胁迫处理,采用便携式光合测定仪测定及荧光测定仪测定其光合指标及荧光特性。[结果]随着土壤水分胁迫的加剧,叶片的净光合速率(Pn)和气孔导度(Gs)下降,胞间CO2浓度(Ci)升高;干旱抑制牡丹净光合作用、限制气体交换,改变光合日变化;水分胁迫(特别是水分过量)时牡丹叶片Fo上升,Fv/Fm下降引起PSⅡ反应中心的失活,但各叶绿素荧光参数在下午又逐渐恢复到上午水平。[结论]75%的土壤相对含水量最适于牡丹的生长;与干旱胁迫相比,水分过多更不利牡丹的生长。两种供试品种中,胡红比洛阳红更耐旱,适应性更广。

Effects of Water Stress on Photosynthesis and Fluorescence Characteristics in Peony

[Objective] Study on the photosynthesis and fluorescence characteristics in peony under water stress.[Method] The two peony varieties Huhong and Luoyanghong were treated by different water stress for determining the photosynthesis and fluorescence characteristics.[Result] With the aggravation of water stress,the net photosynthetic rate(Pn) and stomatal conductance(Gs) decreased,while the intercellular CO2 concentration(Ci) increased.Drought could decrease Pn,constrain gas exchange and change the daily photosynthesis.Fo of peony leaf increased and Fv/Fm decreased under water stress especially water logging,causing the inactivation of the PS II reaction center,and the chlorophyll fluorescence characters gradually recovered until afternoon.[Conclusion] The 75% soil relative water content(SRWC) is the best condition for growth of peony.Compared with drought,water logging is more unfit for the growth of peony.For the two varieties,Huhong assumed more tolerance to drought,accordingly more adaptability.