摘要 : The tank-bromeliad Guzmania monostachia is a heteroblastic epiphyte with great photosynthetic plasticity; however, few studies have investigated the potential relevance of variations in density and structure of trichomes during th... 展开 The tank-bromeliad Guzmania monostachia is a heteroblastic epiphyte with great photosynthetic plasticity; however, few studies have investigated the potential relevance of variations in density and structure of trichomes during the ontogenesis of tank bromeliads. This study hypothesized that both number and cellular organization of trichomes vary according to tank development in G. monostachia rosettes. The frequency of trichomes and their cellular organization were evaluated in younger, intermediate, and older leaves of both atmospheric and mature-tank rosettes. Both adaxial and abaxial surfaces of different portions along the leaf blade of all the leaves were analyzed. Complementary histochemical analyses were performed with trichomes displaying the highest degree of structural specialization. Atmospheric plants presented the most uniform pattern of trichome distribution and cellular organization, while mature-tank plants showed a greater number of trichomes on the adaxial leaf surface and their cellular structures varied both along the leaf blade and during rosette development. Unlike the simpler arrangement of trichome cells covering all leaves of atmospheric plants, mature-tank rosettes had trichome shields typically formed by more cells, with the portions with the highest degree of specialization in trichome structure being the base of intermediate and older leaves. Histochemical evidence revealed living cells in both ring and wing cells of trichome shields, with specific cell types potentially displaying varied absorptive functions. Therefore, with the tank establishment, there is a shift in which the distribution of trichomes changes and shields of trichomes reach the maximum potential complexity in number of cells. 收起