de Pinto M C, Ros Barceló A
Istituto di Botanica, University of Bari, Italy.
Eur J Histochem. 1997;41(1):17-22.
The cytochemical localization of the phenol oxidases, laccase and peroxidase, has been studied in pro-lignifying and lignifying Coleus blumei stem sections using 4-methoxy-alpha-naphthol as substrate. The results illustrated that, for short incubation times, both pro-lignifying and lignifying Coleus sections showed H2O2-dependent phenol oxidase (peroxidase-like) activity in epidermal and vascular tissues, while no detectable H2O2-independent phenol oxidase (laccase-like) activity was found in Coleus tissues. For long incubation times, H2O2-independent phenol-oxidases can also be detected in these tissues, however, this is probably due to the partial capability of intercellular washing fluid Coleus peroxidase to oxidize 4-methoxy-alpha-naphthol in the absence of exogenously added H2O2. This illustrates not only the importance of the substrate used, but also the importance of the incubation time, in the cytochemical localization of phenol oxidizing enzymes.
以4-甲氧基-α-萘酚为底物，研究了彩叶草茎段在木质化前期和木质化过程中酚氧化酶（漆酶和过氧化物酶）的细胞化学定位。结果表明，在较短孵育时间内，木质化前期和木质化过程中的彩叶草茎段在表皮和维管组织中均表现出依赖H₂O₂的酚氧化酶（类过氧化物酶）活性，而在彩叶草组织中未检测到不依赖H₂O₂的酚氧化酶（类漆酶）活性。在较长孵育时间下，这些组织中也能检测到不依赖H₂O₂的酚氧化酶，但这可能是由于彩叶草过氧化物酶在没有外源添加H₂O₂的情况下，具有部分氧化4-甲氧基-α-萘酚的能力。这不仅说明了所用底物的重要性，也说明了孵育时间在酚氧化酶细胞化学定位中的重要性。
