E. D. Vwioko

Soil contamination by heavy metals especially chromium (vi) oxide is a major environmental concern due to its toxicity and persistence inagricultural soils. This study investigated the effect of chromium (VI) oxide on the growth and anatomy of Sorghum bicolor to assess its tolerance and sensitivity. Sorghum seeds were subjected to five concentrations of chromium (VI) oxide (0, 30, 50, 70, and 100 ppm) in soil, under a completely randomized design (CRD) with four replicates per treatment. Growth parameters, including germination percentage, plant height, stem girth and number of leaves, were studied and recorded up to six weeks after planting (WAP). Anatomical analyses of root and stem transverse sections were performed to assess internal tissue responses. Results showed a concentration specific decline in all growth parameters, with the control plants exhibiting the highest mean values for germination percentage (20.00%), plant height (59.50cm) and stem girth (0.84cm) and the least values for germination percentage (10.75%), plant height (36.00cm) and stem girth (0.76) recorded for plants grown in 100 ppm Cr6+ treatment. Vegetative growth parameters decreased with increasing chromium concentration, indicating growth suppression. Anatomical observations revealed darkening of the epiblema and loss of cortical cells in the root of plants as well as deposition of crystal-like substance is observed in the cortex of the stem of plants exposed to higher chromium levels. These alterations indicate that chromium induces oxidative stress and structural injury, disrupting normal cell function and secondary growth. The findings support that chromium (VI) exerts significant inhibitory effects on both morphological and anatomical development of Pennisetum glaucum, emphasizing the detrimental impact of chromium contamination on crop productivity.

Light intensity is a critical environmental factor that profoundly influences plant architecture and development, often by modulating internal phytohormone levels. Specifically, the regulation of auxin biosynthesis and signaling is central to understanding how plants adapt their growth in varying light conditions. The aim of this study was to investigate the expression of key auxin biosynthesis-related genes in Trichosanthes cucumerina plants cultivated under contrasting open field and shaded field conditions within a lowland rainforest environment. This research utilized three distinct data types, morphological, anatomical, and molecular. Morphological data, including vine length, number of leaves, stem circumference, were collected through direct field measurements throughout the growth period. Anatomical data were generated by preparing and microscopically examining cross-sections of stem and root tissues to assess cellular integrity and vascular bundle differentiation. Molecular data were generated via Quantitative Polymerase Chain Reaction (qPCR) analysis, which provided relative gene expression levels for auxin biosynthesis genes (e.g., YUCCA and TAA1) from extracted plant RNA. Morphological and molecular data were subjected to appropriate statistical analysis (e.g., t-tests or 2⁻ΔΔCₜ) method, to determine significant differences between the two growth environments