摘要
研究了 35、 4 0、 4 5和 5 0℃高温处理 0～ 6 0min对甜椒净光合速率 (Pn)、细胞间隙CO2 浓度 (Ci)、气孔导度 (Gs)、蒸腾速率 (Tr)以及叶绿素荧光参数的影响。结果表明 ,35和 4 0℃处理下 ,Pn随Ci的下降而下降 ,而 4 5和 5 0℃处理下 ,Pn明显下降 ,但Ci在 4 5℃下变化不大 ,5 0℃下增加 ,Gs的变化与Tr呈显著正相关。表明在严重的高温胁迫下光合抑制主要是由于非气孔限制引起 ,而在胁迫较轻时 ,可能主要是通过气孔限制。蒸腾作用对气孔导度的敏感性高于光合作用。叶绿素荧光参数Fv/Fm、Fm、Fo在 35和 4 0℃处理下变化不大 ,而 4 5和 5 0℃处理下Fv/Fm、Fm明显下降 ,但Fo上升 ,处理结束后置于 2 5℃下 2 4h后都能得到恢复 ,表明短期高温下光系统II的可逆性失活是光抑制的主要原因。
Effects of four temperatures (35, 40, 45 and 50 ℃) on photosynthetic rate(Pn), concentration of internal leaf CO 2 (Ci), stomatal conductance(Gs), transpiration rate(Tr)and chlorophyll fluorescence in sweet pepper were studied. The results showed that when plants were treated with 35 and 40℃, Pn decreased with the decreasing of Ci. When plants were treated with 45 and 50℃, Pn decreased considerably, Ci changed slightly at 45℃ and increased at 50℃. Changes of Gs were positively correlated with Tr. It could be concluded that inhibition of photosynthesis at extreme high temperature stress resulted from nonstomatal limitations, but stomatal limitations lead to inhibition of photosynthesis when plants were under mild high temperature stress. The change of transpiration was more sensitive to stomatal conductance than photosynthesis. Fluorescence parameters such as Fv/Fm, Fo and Fm were hardly changed under 35 and 40℃, but Fv/Fm and Fm were reduced , Fo was increased at 45 and 50℃.After recovery at 25℃ for 24 hours , Fo, Fm and Fv/Fm were almost entirely restored. The results suggested that reversible inactivation of PSII is the main factor leading to photosynthetic inhibition under short terms of high temperature stress.
出处
《园艺学报》
CAS
CSCD
北大核心
2001年第6期517-521,共5页
Acta Horticulturae Sinica
基金
国家自然科学基金重点资助项目 (39830 2 30 )
关键词
甜椒
高温胁迫
光合作用
叶绿素荧光
Pepper
High temperature stress
Photosynthesis
Chlorophyll fluorescence
