In vitro Bioassay of Allelopathic Activities of a Mangrove Tree, Kandelia obovata, and Fast-growing Trees, Betula platyphylla and Populus alba, Using Protoplast Co-culture Method

Abstract

Allelopathic activities of a salt-tolerant and low-temperature tolerant mangrove tree, Kandelia obovata, which grows in brackish water regions of sub-tropical areas, and two fast-growing trees, Betula platyphylla and Populus alba, which grow in the temperate area, were examined by two in vitro bioassay methods, the sandwich method using dried leaves and the protoplast co-culture method using leaf protoplasts. Lettuce root growth examined by the sandwich method, was inhibited 50% by 50 mg dried mature leaves of K. obovata. In the protoplast co-culture method, inhibition rates of cell division of lettuce protoplasts were 31% and 69% by leaf protoplasts of K. obovata at densities of 1 × 104 mL-1 and 5 × 104 mL-1, respectively. These results were compared with the inverse relationship between allelopathic activities and salt tolerance of mangrove plants of different families. B. platyphylla showed 37% inhibition by the sandwich method using dried young leaves, but only 10% inhibition at 5 × 104 mL-1 by the protoplast co-culture method using leaf protoplasts of B. platyphylla. Dried young leaves of P. alba showed 66% inhibition, but the leaf protoplasts at the density of 5 × 104 mL-1 showed highly stimulatory activity. Abscisic acid, of which contents in leaf protoplasts of three tree species varies from high to low in relation to salt tolerance and recalcitrance of tissue culture, was discussed as a putative allelochemical.

Strong Allelopathic Activities of Leaves and Cultured Cells of <i>Spiraea thunbergii</i> Assayed by the Protoplast Co-Culture Method with Digital Image Analysis: Evaluation of <i>Cis</i>- and <i>Trans</i>-Cinnamic Acid as Allelochemicals

“…By contrast, leaf protoplasts of poplar (200%) and birch (60%) strongly stimulated growth of co-cultured lettuce protoplasts at the cell division stage, but only moderately inhibited growth in the seedling growth test (the sandwich method). These phenomena were explained by the effects of an allelochemical, abscisic acid (ABA) [39] (4.2.2).…”

“…However, ABA was stimulatory at 0.1 -10 µM while the antagonistic plant hormone, gibberellic acid, was inhibitory on lettuce protoplast growth [10]. ABA and its contents were discussed as an allelochemical with stimulatory and less inhibitory activities in leaf protoplasts of poplar and birch in studies using the protoplast co-culture method (4.1.2) [39].…”

In vitro Bioassay of Allelopathic Activities of Soybean, and Three Isoflavones, Using Protoplast Co-culture Method with Digital Image Analysis

“…Though, at the lowest soybean protoplast density tested (5 × 10 3 mL -1 ), large colony formation of lettuce was occasionally observed. Similarly, yellow pigment accumulation was not inhibited after a long protoplast culture period using protoplasts of a mangrove tree, Kandelia obovata (Sasamoto et al,, in preparation), in which the inhibitory pattern at early growth stages (Sasamoto & Yokota, 2021) was similar to that observed in soybean (Figure 6). In contrast, Kudzu showed some inhibitory allelopathic activity at the yellow pigment accumulation stage (Kobayashi et al, 2021).…”

“…Analysis by the sandwich method, revealed higher activity in young leaves of potted plants (Mori et al, 2015) than in leaves of field-grown mature plant of leguminous Mucuna gigantea (Fujii & Hiradate, 2003). Differences in the allelopathic activities with the in vitro bioassay methods, i.e., the sandwich method and protoplast co-culture method, have been reported using several plants and putative allelochemicals, e.g., four bamboo species (Ogita & Sasamoto, 2017), poplar, birch and abscisic acid (Sasamoto & Yokota, 2021), and Spiraea thunbergii and trans-cinnamic acid (Suzuki et al, 2021).…”

Mg2+ Ions Stimulate both Helical Protoplast-Callose-Fiber Formation and Protoplast Division in a Mangrove Tree, Sonneratia caseolaris: Analysis of Sub-fibril Structures of PCF by Atomic Force Microscopy

“…High concentrations of Mg 2+ ions were reported to stimulate protoplast growth in the leaf protoplast culture of another mangrove plant, Kandelia obovata (Kaai et al, 2006;Sasamoto & Yokota, 2021).…”