Alleopathy Laboratory, Department of Botany, Aligarh Muslim University, Aligarh, 202002, India.
Department of Biological Sciences, Faculty of Science, King Abdulaziz University, Jeddah, 21589, Saudi Arabia.
Protoplasma. 2019 May;256(3):857-871. doi: 10.1007/s00709-018-01343-1. Epub 2019 Jan 17.
The stress induced by allelochemicals present in stem aqueous extract (SAE) of Nicotiana plumbaginifolia on alterations in growth, ultrastructure on Cassia tora L., and mitotic changes on Allium cepa L. were inspected. Application of SAE at different concentrations (0.5, 1, 2, and 4%) expressively reduced the growth of C. tora in terms of seedling length and dry biomass. Moreover, the ultrastructural variations induced in the epidermis of Cassia leaf (adaxial and abaxial surface) of 15-day-old saplings were analyzed through scanning electron microscopy (SEM). The variations noticed are rupturing and shrinking of cells along epidermis; damaged margins, extensively curled leaf apex along with the appearance of puff-like structures, grooves, and thread-like structures on the leaf surface. The epidermal cells of samples exposed to treatment no longer appear smooth relative to control, besides showing necrosis as well. Upon exposure to different concentrations of extract, A. cepa root tip cells showed aberrations in chromosome arrangement and disparity in the shape of the interphase and prophase nuclei along various phases of mitotic cycle as compared to control. The mitotic index (MI) showed a concentration-dependent decline in onion root tips exposed to SAE. The aberrations appearing frequently were formation of multinucleated cells, sticky metaphase and anaphase with bridges, sticky telophase, disturbed polarity, etc. The results also show the induction of elongated cells, giant cells, and cells with membrane damage by extract treatment. To our knowledge, this is the first gas chromatography-mass spectrometry (GC-MS) analysis of the methanolic extract of N. plumbaginifolia stem. Overall, 62 compounds were reported, covering 99.61% of the entire constituents, which can be considered responsible for the allelopathic suppression of C. tora. The chief component was 4-tert-butylcalix[4]arene with the highest composition of 19.89%, followed by palmitic acid (12.25%), palmitoleic acid (8.23%), precocene 2 (7.53%), isophytyl acetate (4.01%), and betastigmasterol (3.95%).
研究了叶水提物中化感物质对蓝猪耳生长、超微结构和洋葱根尖有丝分裂的影响。不同浓度（0.5、1、2 和 4%）的叶水提物明显降低了蓝猪耳幼苗的生长，表现为苗长和干生物量减少。此外，通过扫描电子显微镜（SEM）分析了 15 天大苗叶片表皮（上、下表皮）的超微结构变化。注意到的变化是表皮细胞的破裂和收缩；叶缘受损，叶片尖端严重卷曲，同时出现泡状结构、凹槽和线状结构；与对照相比，暴露于处理的样品的表皮细胞不再光滑，并且还显示出坏死。不同浓度的提取物暴露后，洋葱根尖细胞的染色体排列出现异常，有丝分裂周期各期的间期和前期核的形状出现差异，与对照相比，有丝分裂指数（MI）下降。出现的异常包括多核细胞的形成、中期和后期粘滞、末期粘滞、极性紊乱等。结果还表明，提取物处理会诱导伸长细胞、巨细胞和细胞膜损伤的细胞。据我们所知，这是首次对蓝猪耳茎甲醇提取物进行气相色谱-质谱（GC-MS）分析。总的来说，报告了 62 种化合物，占整个成分的 99.61%，可认为这些化合物负责对蓝猪耳的化感抑制。主要成分为 4-叔丁基杯[4]芳烃，含量最高，为 19.89%，其次为棕榈酸（12.25%）、棕榈油酸（8.23%）、早熟素 2（7.53%）、异戊基乙酸酯（4.01%）和β-谷甾醇（3.95%）。
