比较了荒漠短命药用植物托里阿魏(Ferula krylovii)及其伴生的非短命植物骆驼蓬(Peganum harmala)的呼吸和光合作用的温度响应。结果表明:以每克叶片鲜重耗氧量为基础的叶片呼吸速率来看,托里阿魏在30 ℃时突然出现呼吸速率的大幅度跃迁,在温度达到35 ℃时出现了呼吸系统快速失活现象,在45 ℃时呼吸速率达到20 ℃的3.1倍。相比之下,骆驼蓬叶片在20～45 ℃的呼吸速率没有明显的变化,也没有出现呼吸系统的失活现象。这说明,与处于同一生境的非短命植物骆驼蓬相比,托里阿魏的呼吸系统对温度变化有高度的敏感性,对高温的耐受性较差。托里阿魏叶片的光合作用在20～35 ℃连续升高并明显高于骆驼蓬,在35 ℃时达到最高点,在40～45 ℃时光合系统在光照条件下数分钟内快速失活。相比之下,骆驼蓬叶片的光合作用在40 ℃时达到最大值,在45 ℃时光合速率略有下降,但在20～45 ℃始终保持准线性变化,没有出现失活,表明夏季不休眠的骆驼蓬叶片的光合系统对高温有较高的耐受性。由于托里阿魏无论是呼吸和光合系统对温度的耐受性都明显低于非短命植物骆驼蓬,这种代谢上对温度的敏感性差异,可能是导致托里阿魏进入初夏休眠的主要因素。

The effect of temperature on respiration and phoosynthesis wwere investigated in an ephemeral medicinal plant Ferula krylovii Korov in comparison with an non-ephemeral plant Peganum harmala L. In terms of the respiration rate based on the oxygen consumption per gram fresh leaf, an abrupt rise in respiration rate when the temperature was raised to 30 ℃ was observed in P. harmala, further temperature increase to 35 ℃ or above resulted in fast deactivation of the respiration system. The respiration rate at 45 ℃ reached 3.1 times high over that at 20 ℃. In contrast, through the entire tested temperature range, neither abrupt rises in respiration rate, nor fast deactivation of the respiration system was observed in P. harmala. In addition, even the respiration rate did not show significant change in response to the temperature change. This was an indication that the respiration system in F. krylovii was much more sensitive to temperature change and more vulnerable to higher temperatures compared with P. harmala. On the other hand, the photosynthetic rate of leaves in F. krylovii increased steadily to a maximum with the rise in temperatures from 20 to 35 ℃ and was constantly higher than that of leaves in P. harmala. in this temperature range, but the photosynthetic system showed fast deactiviation within a few minutes when the temperature was raised to 40 ℃ and above. On the contrary, the photosynthetic rate of leaves in P. harmala. reached its height at 40 ℃, declined slightly at 45 ℃, but a close linear rate was kept and no sign of photosynthetic deactivation was observed, indicating that the photosynthetic system in P. harmala. was highly resistant to higher temperature stress. Because either the respiration or the photosynthetic system was all more sensitive to higher temperatures in F. krylovii than in P. harmala, this sensitivity may be one of the main reasons leading to the dormancy of F. krylovii in early summer.