摘要
以鲁林1号杨扦插苗为试材,采用盆栽控水试验,研究不同干旱胁迫处理对杨树苗叶片相对含水量、光合速率、叶绿素荧光及相关生理指标的影响。结果表明,随着胁迫时间的延长,杨树苗叶片的相对含水量、净光合速率(Pn)和气孔导度在轻度胁迫下缓慢降低,而在中度和重度胁迫下迅速降低;胞间CO2浓度在轻度胁迫下缓慢下降,在中度胁迫下先降后升,而在重度胁迫下一直升高,表明Pn的降低在轻度胁迫下是由气孔因素引起,中度胁迫下是由气孔因素和非气孔因素共同引起,而在重度胁迫下是由非气孔因素引起。随着胁迫时间的延长,叶片的PSⅡ原初光能转化效率和光化学猝灭系数在轻度胁迫下缓慢降低,而在中度和重度胁迫下快速降低;非光化学猝灭系数在轻度胁迫下显著升高,而在中度和重度胁迫下先升高后降低;叶片SOD和POD活性先升高后降低。因此,轻度胁迫下杨树苗通过热耗散和抗氧化酶活性调节的协同作用稳定了光合机构的功能,Pn降低主要受气孔限制因素影响;而中度和重度胁迫下光系统Ⅱ和抗氧化酶系统损伤,是Pn降低的非气孔限制因素。
Poplar （PopulusבLulin-1’） seedlings grown in pots were subjected to four different water treatments （normal irrigation, light drought, moderate drought and severe drought）. The relative water content, gas exchange, chlorophyll fluorescence parameters and protective enzyme activities in leaves of poplar were tested. The results indicated that with the extension of drought stress time, the relative water content, net photosynthetic rate （Pn） and stomatal conductance （gs） in leaves of poplar decreased gradually under light drought stress, while decreased rapidly under both moderate and severe drought stress. Furthermore, the intercellular CO2 concentration （Ci） decreased tardily under light drought stress, increased after an initial decrease under moderate stress and increased all the time under severe stress. This suggested that reductions in Pn resulted from stomatal limitations under light drought stress, from both stomatal and non-stomatal limitations under moderate drought stress and from non-stomatal limitations under the severe drought stress. At the same time, the maximal photochemical efficiency of PSⅡ （Fv/Fm） and photochemical quenching coefficient （qP） in leaves of poplar declined slowly under light stress, however, declined quickly under both moderate and severe stress. The non-photo chemical quenching coefficient （NPQ） increased significantly under the light drought stress, but had a trend of increasing firstly and decreasing then under either moderate or severe drought stress. Additionally, the activities of superoxide dismutase （SOD） and peroxidase （POD） in leaves decreased after an initial increase. As a result, under the light drought stress the decreased Pn were mainly owing to stomatal limitations through stomatal regulation, the enhance of thermal dissipation and antioxidant enzyme jointly; under the moderate and severe drought stress major non-stomatal limitations responsible for reduction in Pn were associated with the impairment of PSⅡ and anti
出处
《核农学报》
CAS
CSCD
北大核心
2014年第3期532-539,共8页
Journal of Nuclear Agricultural Sciences
基金
山东省农业重大应用技术创新课题"杨树超高产栽培关键技术研究"
关键词
鲁林1号杨
干旱胁迫
气体交换
叶绿素荧光
抗氧化酶
Populus× ＇ Lulin - 1 ＇
Drought Stress
Gas Exchange
Chlorophyll Fluorescence
Antioxidant Enzyme
