TITLE:
Strong Allelopathic Activities of Leaves and Cultured Cells of Spiraea thunbergii Assayed by the Protoplast Co-Culture Method with Digital Image Analysis: Evaluation of Cis- and Trans-Cinnamic Acid as Allelochemicals
AUTHORS:
Sakae Suzuki, Mari Kimura, Rei Yasuda, Naoya Wasano, Yutaka Sasamoto, Yoshiharu Fujii, Hamako Sasamoto
KEYWORDS:
Allelopathy, Cinnamic Acid, Protoplast Co-Culture, Spiraea thunbergii
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.12 No.11,
November
24,
2021
ABSTRACT: The inhibitory allelopathic activities of leaves and
leaf-origin suspension cultured cells of Spiraea thunbergii, and putative allelochemicals, cis-
and trans-cinnamic acid, were investigated by the protoplast co-culture
method with digital image analysis (DIA-PP method) using lettuce as a
recipient. The optimal conditions of 2,4-dichlorophenoxyacetic acid (2,4-D) and
benzyladenine (BA) for the cell division of S. thunbergii protoplasts were first examined using 50 μL
liquid MS basal medium containing 3% sucrose, and 0.8 M mannitol in a 96-well
culture plate. The hormonal condition for co-culture, 1 μM 2,4-D plus 0.1 μM
BA, which was optimal for lettuce protoplast growth, was sub-optimal for S. thunbergii protoplasts.
Effects of co-culture on the three stages of lettuce protoplast growth, i.e.,
cell wall formation, cell division, and yellow pigment accumulation, were
examined. Protoplasts of leaf and suspension cells of S. thunbergii strongly
inhibited lettuce protoplast growth at the cell division stage (100% inhibition
at 80 - 100 × 103 mL-1), but not so much at the other two
stages. Both cis- and trans-cinnamic acid, showed the strongest
inhibition at the cell wall formation stage, and 100% inhibition at the cell
division stage at 100 μM. These results were compared with those obtained in a
lettuce seedling growth test, using different allelopathic plants, and their
allelochemicals were studied by the DIA-PP method.