摘要
为明确桑树在不同氮形态下光合能力差异以及桑树对不同氮形态的需求规律,以1年生桑树实生苗为试验材料,研究了在硝态氮(NO_3^--N)、铵态氮(NH_4^+-N)以及硝酸铵(NH_4NO_3)(氮素浓度均为7.5 mmol/L)处理下桑树叶片的叶绿素荧光特性。结果表明,桑树叶片在NH_4^+-N下的PSⅡ光化学活性、电子传递速率和光能利用能力明显低于NO_3^--N和NH_4NO_3处理,而NO_3^--N和NH_4NO_3处理之间无明显差异。NH_4^+-N处理下桑树叶片的VJ和VI均较NO_3^--N和NH_4NO_3处理明显增加,即PSⅡ反应中心受体侧电子QA向QB传递速率较低,但此时桑树叶片的Sm和N却明显高于NO_3^--N和NH_4NO_3处理,说明导致NH_4^+-N处理下桑树叶片PSⅡ受体侧电子传递能力降低的原因直接与QB功能的降低有关。另外,NH_4^+-N处理下桑树叶片的VK和VL也明显低于NO_3^--N和NH_4NO_3处理,说明桑树叶片OEC活性的抑制与类囊体膜结构的稳定性降低也是导致其叶片PSⅡ反应中心光化学活性在NH_4^+-N处理下降低的重要原因。
In order to determine the photosynthetic capacity and requirement of mulberry for different nitrogen forms,one year old of mulberry seedlings as experimental materials,the chlorophyll fluorescence characteristics of mulberry leaves was studied under three nitrogen forms,in which nitrogen concentration was 7.5 mmol/L with nitrate nitrogen（NO-3-N）,ammonium nitrogen（NH＋4-N）and ammonium nitrate（NH4NO3）.The results showed that the photochemical activity,electron transfer rate and light energy utilization of mulberry leaves in PSⅡ under NH＋4-N were significantly lower than that of NH4NO3 and NO-3-N,while there was no significant differences between NH4NO3 and NO-3-N.The VJ and VI of mulberry leaves were significantly increased by NH＋4-N treatment,that was,QA to QB electronic transmission rate of PSⅡ electronic receptor side were lower.while,the Sm and N were significantly higher than those of NH4NO3 and NO-3-N,which showed that the lower the electron transfer ability of PSⅡcould be related with capacity of receptor side of QB treated by NH＋4-N.In addition,VK and VL of mulberry leaf under NH＋4-N treatment was also lower than that of NO-3-N and NH4NO3,which suggested that the suppressed OEC activity and decreased thylakoid membrane structure stability were the important reasons for reducing photochemical activity in the leaves of PSⅡ reaction centers under the NH＋4-N treatment.
出处
《华北农学报》
CSCD
北大核心
2017年第2期164-170,共7页
Acta Agriculturae Boreali-Sinica
基金
黑龙江省自然科学基金项目(C200917)
关键词
桑树
氮形态
叶绿素荧光
PSⅡ
： Mulberry
Nitrogen form
Chlorophyll fluorescence characteristics
PSⅡ
