湿润条件下几种锦鸡儿属灌木的气体交换特征及调节机制

土壤水分充足时柠条、中间锦鸡儿和小叶锦鸡儿的Pn、E和Gs均大幅度提高,Pn和Gs值的大小顺序为:中间锦鸡儿>小叶锦鸡儿>柠条,E值的大小顺序为:柠条>中间锦鸡儿>小叶锦鸡儿。柠条一日内的Fv/Fo、Fm/Fo和Fv/Fm值最高,日间没有明显的降低;中间锦鸡儿的上述各项荧光参数值最低,且在13:00~ 17:00出现"低谷",说明发生了明显的光合作用光抑制;小叶锦鸡儿各项测值的大小和波动幅度居于两者之间;3种灌木的光抑制均可在黄昏得到恢复。3种灌木的Chl以中间锦鸡儿为高,柠条和小叶锦鸡儿相近;Car的日均值仍以中间锦鸡最高,柠条和小叶锦鸡儿则相近。一日内以柠条的水势最低且波动平缓;中间锦鸡儿和小叶锦鸡儿的水势较高,日间降幅较大,在15:00~ 17:00降至最低。柠条脯氨酸含量在日间明显增加,中间锦鸡儿稍有增加,小叶锦鸡儿则不明显;3种灌木的脯氨酸含量依次为柠条>中间锦鸡儿>小叶锦鸡儿。

Gas Exchange Characteristics and Regulation Mechanism of Several Caragana Shrubs Under Wet Condition

When soil water supply was adequate, the photosynthetic rate (Pn), transpiration rate (E) and stomatal conductance (Gs) of Caragana korshinskii, C. intermedia and C. microphylla increased greatly. The Pn and Gs values of the three shrubs were in order: C. intermedia > C. microphylla > C. korshinskii; the E values in the order: C. korshinskii > C. intermedia > C. microphylla. The diurnal chlorophyll fluorescence parameters of C. korshinskii, including Fv/Fo, Fm/Fo and Fv/Fm, were the highest and no significant reduction was observed in the daytime; the corresponding parameters of C. intermedia were the lowest and appeared low valley between 13:00~17:00, which indicated an obvious light suppression to the photosynthesis. The measured values of C. microphylla fluctuated between that of the above two species. The light suppression to the photosynthesis of the three shrubs terminated in the evening. Among the three shrubs, C. intermedia had a higher chlorophyll content, while the corresponding values of C. korshinskii and C. microphylla were approximate; the diurnal mean carotene content of C. intermedia was the highest, while C. korshinskii and C. microphylla had an approximate carotene content values. The water potential of C. korshinskii in a day was the lowest and fluctuated gently, while the corresponding values of C. intermedia and C.microphylla were higher and had larger diurnal reduction amplitude. Furthermore, they reached a lowest value between 15:00~17:00. The proline content of C. korshinskii in the daytime increased significantly, the corresponding value of C. intermedia also slightly increased but the increase in proline content of C. microphylla was not noticeable. In terms of the proline contents of the three shrubs they were arranged in the order: C. korshinskii > C. intermedia > C. microphylla.