小叶锦鸡儿离体叶片对温度处理的某些生理响应

Some Responses of Detached Leaves of Caragana microphylla Lam. after Temperature Treatments

小叶锦鸡儿离体叶片分别经25、30、35、40、45、50、55℃等7个温度处理60min后,测定了其光系统Ⅱ最大量子效率(Fv/Fm)和脯氨酸含量的响应。结果表明,25～40℃的温度对Fv/Fm没有明显影响;温度高于40℃,首先使光合作用通过光系统Ⅱ的电子传递受到不同程度的阻抑;当温度高于50℃,使叶片光系统Ⅱ反应中心失活或破坏,即小叶锦鸡儿叶片光系统Ⅱ反应中心可耐受的最高温度为50℃,温度再高,将对叶片造成高温伤害。另外,在耐受范围内,叶片中的脯氨酸含量可能表征了叶片遭受温度胁迫的程度。

Detached leaves of Caragana microphylla Lam. were submitted to seven sets of temperature treatments, i.e., 25℃, 30℃, 35℃, 40℃, 45℃, 50℃ and 55℃ for 60 minutes respectively. The potential quantum yield of photosystem Ⅱ (PSⅡ) and proline contents were assayed. The results showed that temperature treatments higher than 40℃ would decrease the maximal quantum yield of PSⅡ (F_(v)/F_(m)), while temperature from 25℃ to 40℃ had no apparent effects on F_(v)/F_(m). Temperature treatments higher than 40℃ influenced leaf photosynthesis by inhibiting the electron transfer through PSⅡ. And the reaction centers of PSⅡwould be damaged or reversibly inactivated under the treatment higher than 50℃, meaning that the highest temperature PSⅡreaction centers could tolerate was about 50℃. Beyond this point, the temperature damage would occur to leaves. In addition, poline content in treated leaves was an index of the degree of temperature stresses in the temperature range leaves could tolerate.