对甘草试管苗炼苗过程中气孔行为、叶片蒸腾及光合能力的变化规律及特点进行了研究,并分析了试管苗炼苗过程中出现的叶片蒸腾及气孔导度的波动现象.甘草试管苗的炼苗过程设计为4个阶段:试管苗、蛭石苗、营养袋苗和土壤苗,在高光强及低湿度的自然条件下测定,气孔导度(ga)、叶片蒸腾速率(E)及胞间CO2浓度(CO2.int)随着炼苗的进展逐渐下降,净光合速率(Pn)逐渐增加,可见通过炼苗提高了叶片保水能力及光合能力.将各炼苗阶段的甘草幼苗在各自炼苗阶段的具体条件下连续测定,发现在炼苗开始的前几天,蛭石苗和营养袋苗叶片的蒸腾速率及气孔导度具有显著的波动,而胞间CO2浓度和净光合速率则比较稳定.这种蒸腾速率及气孔导度的波动可能与炼苗过程中湿度下降所引起的水分平衡的破坏密切相关,并具有防止水分过度散失的作用.%The stomatal behavior, leave transpiration and photosynthetic ability were studied during acclimatization of G. uralensis seedling in vitro. The acclimatization procedure was divided into 4 stages:seedlings in vitro, seedlings in vermiculite, seedlings in nutrition bag and seedlings in soil With the proceeding of the acclimatization, the stomatal conductance (ga),leave transpiration (E) and intercellular CO2 concentration (CO2. int) reduced, while the net photosynthetic rate (Pn) increased gradually when measured in the condition of low humidity and high illumination,the above results showed that the mechanism and the very reason that through acclimatization the seedlings gradually adapted to the natural ambient. During successive measurement in each unique ambient of its acclimatization stage, it was discovered that the ga and E of the seedlings in vermiculite and seedlings in nutrition bag had an evident fluctuation in the first few days when the seedlings were kept in the new ambient, while the Pn and CO2. int of these seed lings showed no fluctuation. The cyclical changes of E and ga during acclimatization may becaused by the disturbance of water balance such as the decrease of the relative humidity and the increase of illumination intensity in the microenvironment, and the fluctuation of ga and E may act as a protective mechanism to prevent excessive water loss.
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