用气体交换和叶绿素荧光法研究黄柏剥皮后的再生机理

应用植物气体交换和叶绿素荧光技术,测定了5年生黄柏主干环状全剥皮及新皮再生对叶片光合效率、蒸腾速率以及叶绿素荧光的影响。结果表明,剥皮后7-29d,其光合效率、叶绿素荧光最大量子效率ΦPO、实际量子效率ΦP’和光化学猝灭qp均显著低于对照(未剥皮树),35d后与对照无显著差异;而蒸腾速率与对照无显著差异。说明剥皮导致的光合下降不是由气孔因素引起,也不是光系统结构的破坏,而是因剥皮阻断了光合碳同化物向下运输,从而发生光合产物积累对光合作用过程的反馈抑制。一旦韧皮部向下运输的功能恢复,反馈抑制随即解除,光合作用迅速恢复至常态。

USING GAS EXCHANGING AND CHLOROPHYLL FLUORESCENCE METHOD TO STUDY BARK REGENERATION MECHANISM OF BARKED Phellodendron chinense

Complete circularity-decortication and bark regeneration on the trunk of 5-years old P.chineness were done and the photosynthetic rate,transpiration rate and chlorophyll fluorescence were measured by plant gas exchanging method and chlorophyll fluorescence method to analyze the mechanism of bark regeneration.The results indicated that photosynthetic efficiency,maximum quantum efficiency of chlorophyll fluorescence(Φ_PO),actual quantum efficiency(Φ_P') and photochemical quenching coefficient(q_p) were significantly lower than those of non-barking control during 7-29d bark removing,whereas no significant difference was observed after 35d barkremoving.The results also suggested that the change of transpiration rate was no significant difference after decortication.Therefore,it was concluded that decline in photosynthetic rate was neither caused by stoma nor by structural damage of photosystem.The date showed that transportation downwards of photosynthetic carbon-assimilations in the leaves was obstructed by bark removing,which that feedback inhibition to photosynthetic process was induced by accumulation of photosynthetic products.However,feedback constraint released as soon as function of phloem for transportation downwards recovered,and the photosynthesis rapidly restored to normal level.