PLANT BIOLOGY AND BIOTECHNOLOGY

Heavy metal contamination, particularly lead (Pb) and cadmium (Cd) pollution, poses significant challenges to agricultural productivity and plant health. In this study, Corchorus olitorius was grown in soils treated with different concentrations of lead nitrate and cadmium chloride solutions. The heavy metal treatments applied were 50 and 100 ppm Cd; and 100 and 200 ppm Pb. The application of heavy metal solution was carried out eight times and these concentrations were chosen based on literature. The experiment was conducted as a field potted study. Each treatment was replicated four times. Field data were recorded for germination, which includes; plant height, stem girth, and number of leaves produced per plant. Biochemical analyses for chlorophyll, carotenoids and lycopene contents were also done. Spectral indices for stress in plants were carried out spectrophotometrically by scanning leaf extracts using 200 – 900nm wavelengths. Findings from this study shows that cadmium and lead pollution on jute plant induced faster and higher mean germination percentage of 58.75% with moderate concentration
of cadmium treatment (50ppm), compared to the control treatments which had a slower and a
low mean percentage germination of 26.8%. In terms of mean plant height, plants grown in
200ppm of lead nitrate had the highest plant height which measured 49.00cm compared to
control which had plant height of 40.50cm, while 50ppm cadmium had the least mean plant
height of 27.75cm, which were observed nine weeks after planting. Spectrophotometric analysis
was done, which indicated that the plants had a weak absorption of green wavelengths, but a
stronger absorbance range was observed in 200-400 nanometers (nm). Cadmium 50ppm had the
highest chlorophyll concentration while the least was observed with 100ppm lead. Findings from
the study concluded that heavy metals may enhance the growth of the plant but further research
should be carried out to evaluate the prolonged effects of heavy metal stress on the plant.

The objective of this study is to determine the physiochemical composition and microbiological analysis to determine the storability of Sweet potato tubers, sold at New Benin Market, Edo state. Two cream skinned sweet potato tubers were obtained at New Benin Market, Edo state and stored in a laboratory for a period of time . In the laboratory, physiochemical tests were conducted on the potato samples to determine the moisture content, dry matter content, acidity, titratable acidity, and vitamin content. Microbiological evaluation of the sweet potato tubers was conducted in the laboratory, using laboratory techniques of isolating fungi, this involves the preparation of PDA, the physiochemical and microbiological assessment was carried out on one of the potato tubers the day it was obtained and the results was used as control for the experiment ,after 40 days the same physiological and microbiological tests were conducted on the stored sweet potato tuber in the laboratory. There was a slight decline in the physiochemical composition of the sweet potato tuber after 40 days of storage. The microbiological test confirmed the presence of spoilage inducing fungi on the sweet potato tuber after 40 days of storage, the occurrence of these fungi confirmed that the potato tuber stored has undergone spoilage. Through this research it was determined that sweet potato tubers exhibit a good storage capacity, as evidenced by the minimal variance in their physiochemical composition even after a 40-day storage period.

Hydropriming has proved to be the most potent form of seed germination enhancement in not just final germination but also in speed of germination and time taken to reach 50% of total germinated seeds of Napoloenaea vogelii Hook. and Planch. Priming seeds in solutions significantly affected seed germination (P<0.05), with smoke water treatments, hydro and halopriming having significantly higher germination means Maximum germination percentage was observed in hydropriming with 90% germination while Halopriming (NaCl 2, and 4g/l) had total germination percentages of 85% each. Napoleonaea vogelii seeds also responded positively to smoke water treatment for 10 and 20 minutes with 80% and 77.50% respectively. Effect of bush fire proved to be deleterious, showing the lowest germination percentage of 32.50%. Seeds collected from decaying fruits on trees has low mean germination percentage of 34.17%. The effect of various treatments was significant on the speed of germination. All forms of priming showed improved speed of germination with hydropriming being superior with a mean speed of 2.99 day-1. Control showed the least speed with 0.39 day-1. Plants in complete darkness showed the highest mean growth in height (32.42cm) while those in 24hrs light showed lowest growth in height (18.88cm). Hydropriming and Halopriming (2g/l) also showed significant growth in heights (24.12cm and 24.08cm respectively). The seeds of Diospyros barteri Hiern. did not show any germination under all treatments given to seeds.