J Syst Evol ›› 2007, Vol. 45 ›› Issue (1): 39-51.DOI: 10.1360/aps06053

• Research Articles • Previous Articles     Next Articles

Morphological characteristics and biological significance of specialized connectives in Lonicera (Caprifoliaceae)

1JIANG Xing-Shan, 1WU Hong*, 2LUN Xuan, 2LU Dong-Wen   

  1. 1(College of Life Science, South China Agricultural University, Guangzhou 510642, China)

    2(Test Center, South China Agricultural University, Guangzhou 510642, China)
  • Received:2006-05-12 Published:2007-01-18

Abstract: The specialized structure in connectives of anthers generally has important biological significance. However, information about idioblasts that accumulate phenolic compounds in connective is limited; moreover, biological significance of these phenolic idioblasts is unknown. In this study, semi-thin sectioning and cryo-sectioning techniques, and histochemical and cytochemical methods were employed to investigate morphological nature of the idioblasts in connectives of Lonicera. The experimental results showed that the idioblasts in the specialized connectives of Lonicera contained abundant phenolic compounds. In order to explore biological significance of the phenolic idioblasts in the specialized connectives, we observed ultrastructures of the phenolic idioblasts in different developmental stages, and also analyzed relationships of development of parenchyma to vascular bundles in connective of Lonicera. Our observations revealed that distribution, ultrastructure, and developmental process of the phenolic idioblasts were closely related to development of the vascular bundles in connectives, and that accumulation and degradation of phenolic compounds in these phenolic idioblasts happened alternately and regularly. So we inferred that prior to two-cell pollen stage, the specialized connective of Lonicera might be a temporary storage site of phenolic compounds to protect the developing vascular bundles from damage in anthers. By this way, the normal development of microspores and normal pollination could be ensured. However, after that stage, phenolic compounds began degrading. The degradation of these phenolic compounds might spread to other parts within the plant through vascular bundles, in order to provide precursor for synthesizing correlative components or reusing. Furthermore, our research showed that phenolic idioblasts could be a stable structural feature, and had specific distribution sites. All these findings might provide new embryological evidence for unraveling systematic relationships.

Key words: Lonicera, connective, phenolic compounds, development.