Mehal Kulwinder Kaur, Kaur Amarpreet, Singh Harminder Pal, Batish Daizy R
Department of Botany, Panjab University, Chandigarh, 160 014, India.
Department of Environment Studies, Panjab University, Chandigarh, 160 014, India.
Protoplasma. 2023 Jan;260(1):77-87. doi: 10.1007/s00709-022-01761-2. Epub 2022 Apr 20.
Allelopathy has been proposed as an efficient mechanism of invasion by plant species via growth inhibition and suppression of the resident plant community. Verbesina encelioides (Cav.) Benth. & Hook. f. ex A. Gray (golden crownbeard; Asteraceae), a native of south-western USA and Mexican Plateau, is an emerging troublesome invasive weed species of north-western states of India. We investigated the allelopathic potential of the aqueous extracts prepared from the fresh foliage and leaf litter of V. encelioides on its co-occurring species, Amaranthus viridis and Senna occidentalis. Phytotoxicity bioassay showed concentration-dependent (control < 0.5% < 1% < 2% < 4% extract) inhibition of growth and photosynthetic parameters in the test plants. Both the extracts induced ~ 50% inhibition of germination compared to control at 4% concentration. The maximum synthesis effect (collective effect on seedling length and dry weight) was observed to be - 0.69 and - 0.62 in A. viridis and - 0.68 and - 0.57 in S. occidentalis for the fresh leaf and leaf litter extracts, respectively, at 4% concentration. Also, an antagonistic concentration-dependent impact was observed on the photosynthetic pigments (total chlorophyll and chlorophyll a content) and photosynthetic efficiency. The liquid chromatography-mass spectrometry assay of leaf extracts revealed the presence of 15 allelochemicals including phenolic acids, flavonoids, phytosterols, phytophenols, dicarboxylic acid, guanidine, and triterpenes. Of these, 14 compounds were present in both fresh and leaf litter materials. However, a guanidine derivative, galegine, was only found in the fresh leaf material of the plant. The findings support the novel weapon hypothesis and suggest that V. encelioides competitively excludes its neighboring plants by virtue of allelopathic interference.
化感作用被认为是植物物种通过抑制生长和压制本地植物群落来实现入侵的一种有效机制。黄顶菊（学名：Verbesina encelioides (Cav.) Benth. & Hook. f. ex A. Gray）原产于美国西南部和墨西哥高原，是印度西北部各州新出现的一种麻烦的入侵杂草。我们研究了从黄顶菊新鲜叶片和落叶制备的水提取物对与其共生的绿穗苋和望江南的化感潜力。植物毒性生物测定表明，测试植物的生长和光合参数受到浓度依赖性（对照＜0.5%＜1%＜2%＜4%提取物）的抑制。在4%浓度下，两种提取物与对照相比均诱导了约50%的发芽抑制。在4%浓度下，新鲜叶片提取物和落叶提取物对绿穗苋的最大综合效应（对幼苗长度和干重的综合影响）分别为-0.69和-0.62，对望江南分别为-0.68和-0.57。此外，还观察到对光合色素（总叶绿素和叶绿素a含量）和光合效率有拮抗浓度依赖性影响。叶片提取物的液相色谱-质谱分析显示存在15种化感物质，包括酚酸、黄酮类、植物甾醇、植物酚、二羧酸、胍和三萜类。其中，14种化合物在新鲜叶片和落叶中均有存在。然而，一种胍衍生物，鹰嘴豆芽素，仅在该植物的新鲜叶片中发现。这些发现支持了新武器假说，并表明黄顶菊通过化感干扰竞争性地排挤其邻近植物。
