Impact of Bisphenol A on seed germination, radicle length and cytogenetic alterations in Pisum sativum L

Bisphenol A (BPA) is a global transpiring pollutant and an endocrine disruptor present in the environment which has a substantial harmful effect on plants. In the present study, its effects on seed germination, radicle length and cytogenetic alterations were investigated in Pisum sativum L root tip cells. Pisum sativum L seeds were germinated after treating with various concentrations of BPA (2 mg/L, 5 mg/L, 10 mg/L, 15 mg/L, 20 mg/L and 25 mg/L) at 24±1°C for 72 hours and the cytogenetic variations were assessed. The investigation showed that BPA reduced the percentage of seed germination, mitotic index, radicle length (at higher concentrations) and instigated a rise in chromosomal anomalies in a dose-related manner. In total, there is an enhanced occurrence of c-mitosis, stickiness, bridges, fragments and laggards in the BPA treated root tip cells of Pisum sativum L seeds.

Supra-physiological levels of gibberellins/DELLAs modify the root cell size/number and the root architecture in root tips of A. thaliana seedlings. Connections to the root hair patterning and abundance

A previous study (McCarthy-Suarez, 2021) showed that growing A. thaliana seedlings for 5 days under excessive levels of gibberellins (GAs)/DELLAs altered the arrangement, shape and frequency of root hairs in root tips. Because no changes in the distribution or number of root hairs occurred when the gai-1 (gibberellin-insensitive-1) DELLA was over-expressed at the root epidermis, it was concluded that the GAs/DELLAs might regulate the root hair patterning and abundance in A. thaliana seedlings by acting from the root sub-epidermal tissues. In the present study, microscopy analyses showed that excessive levels of GAs/DELLAs also modified the size and number of root tip cells in A. thaliana seedlings. While excessive DELLAs shortened and widened the root epidermal, cortical, endodermal and pericycle cells, excessive GAs, excepting the epidermal cells, generally narrowed them. However, no changes of root cell size occurred when gai-1 was over-expressed at the root epidermis. In addition, high levels of DELLAs often induced extra cells at the root epidermis, cortex, endodermis and pericycle, whereas high levels of GAs sometimes induced extra cells at the root cortex and pericycle. On the other hand, excessive levels of DELLAs enhanced the outgrowth of lateral roots in root tips, unlike excessive levels of GAs. Thus, the results of this study suggest that supra-physiological levels of GAs/DELLAs might modify the size/number of root tip cells by acting from the root sub-epidermal tissues. This, in turn, might impact on the patterning and abundance of root hairs and on the root architecture.

Cytotoxic and micronuclei inducing effects of petroleum ether fraction of leaf aqueous extract of Clerodendrum viscosum Vent. in Allium cepa root tip cells

Clerodendrum viscosum is a traditionally used medicinal plant. The present study aimed to analyze a detailed cytotoxic effect of the nonpolar petroleum ether fraction (AQPEF) of leaf aqueous extract of C. viscosum Vent. (LAECV) in Allium cepa root tip cells. The LAECV was fractionated with petroleum ether and tested for A. cepa toxicity at early hours (2 and 4 h treatment) at concentrations 0, 0.050, 0.100, 0.150 and 0.200 mg mL-1. The highest aberrant cell percentage (10.45%) was scored from 0.150 mg mL-1 followed by0.100 mg mL-1 (8.75%) concentration at 4 h treated samples. The AQPEF treatment induced a significant (p<0.0001) increase in micronuclei frequency; 4.31, 5.08, 5.05 and 3.05% respectively at concentrations 0.50, 0.100, 0.150, and 0.200 mg mL-1. The highest polyploid frequency (20.14%) induced with 0.100 mg mL-1 of AQPEF at 16 h recovery. 0.150 mg mL-1 is the most effective concentration of AQPEF to decipher its activity similar to colchicine (0.150 mg mL-1). In summary, the present study indicates petroleum ether is suitable for extraction of the active phytochemicals of LAECV having cytotoxic effects on A. cepa root tip cells. The AQPEF has colchicine like micronuclei, polyploidy, and mitotic abnormality inducing potentials in A. cepa root apical meristem cells.

Comparative assessment of allelopathic herbicidal actions and total phenolics content of seven Indian medicinal plants

Allelopathy is a vital ecological process that influences the dynamics of ecological succession, structure, and composition of plant communities. The present study aimed to evaluate a comparative account of allelopathic inhibitory actions in relation to total phenolic contents of aqueous extracts from seven traditionally used medicinal plants of India. Triticum aestivum and Cicer arietinum seedlings were used to test seed germination inhibition, seedling growth retardation and branch root sprouting inhibition. Allium cepa root tip cells were used for mitotic index inhibition and abnormal cell percentage analysis. The correlation between the total phenolics content and allelopathic activities was analyzed. The different extracts show the varied degree of allelopathic inhibitory activity. Out of these seven used extracts, Crinum asiaticum leaf extract (CaLAE) showed the highest allelopathic inhibitory action and it could reduce 94.3 and 79.59% root and shoot growth respectively at 96 h of treatment (1 mg/mL) and that was increased to 96.18 and 93.78% respectively with 2 mg/mL. The quantitative phytochemical analysis also revealed that CaLAE also possess relatively higher amounts of total phenolics. The growth retardation effects of the extract are in accordance with the mito-depression and increased chromosomal abnormality in A. cepa root tip cells. In conclusion, Crinum asiaticum may be considered as a prospective source of allelochemicals for plant growth regulation and a source of commercial herbicidal products.